The EAAP series is published under the direction of Siem Korver and Jean Boyazoglu

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This symposium was held as a joint trilingual (english, french, german) session of the seven EAAP Commissions at the occasion of the 41 st annual meeting held in Toulouse (France), 7-12 July 1990.

International organizing committee Prof. J. Coleou Dr A. Roos Prof. J. Espinasse

The presidents of EAAP Commissions: Dr K. Maijala - Animal genetics Prof. J.L. Tisserand - Animal nutrition Dr J. Unshelm - Animal management and health Dr G. Schönmuth - Cattle production Dr T.T. Treacher - Sheep and goat production A. Aumaitre - Pig production B. Langlois - Horse production

Editorial Committee E. Rossier (Compiler) Prof, dr ir R.D. Politiek Dr ir S. Korver DrJ. Boyazoglu D.E. Steane J.C. Flamant

On the eve of the 3rd millennium, the European challenge for animal production Proceedings of the joint symposium of all study commissions of the European Association for Animal Production, Toulouse, France, I I July 1990

Comptes rendus du symposium commun pour toutes les commissions de la Fédération Européenne de Zootechnie, Toulouse, France, I I Juillet 1990

Berichte des für alle Studienkommissionen gemeinsames Symposium der Europäischen Vereinigung für Tierproduction, Toulouse, Frankreich, I I. Juli 1990.

(EAAP Publication No. 48, 1991)

E. Rossier (Compiler)

Pudoc Wageningen 1991

CIP-data Koninklijke Bibliotheek, Den Haag

ISBN 90-220-1012-0 NUGI 835

ISSN 0071-2477

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Contents

Foreword — A. Roos (Sweden) & J. Coleou (France)

Session 1 "Progress in science and technology over the past 20 years" Chairman: R. Février (France); Co-chairman: E.P. Cunningham (Ireland) 5

Introduction — R. Février, chairman (France) 7 Genetic improvement of livestock over the past 20 years — M. Bichard

(United Kingdom) 9 Management of reproduction in farm animals: present and future —

M. Courot & P. Volland-Nail (France) 23 Progress in nutrition and feeding over the past 20 years — F. de Boer

(the Netherlands), H. Bickel (Switzerland) & N. Todorov (Bulgaria) 39 Views on various strategies for development in dairy cattle production —

A. Neimann-S0rensen (Denmark) 51 Synthesis of the 1st session — E.P. Cunningham, co-chairman (Ireland) 63

Session 2 "Future challenges and questions" Chairman: A. Roos (Sweden); Co-chairman: J. Coleou (France) 69

Management of animal material: adjustment to the economic evolution and to production constraints — F. Pirchner, G. Schömuth & D. Flock (FRG) 71

Management of the feeding resources and consequences for the geographical situation of animal production — C. Beranger (France) 79

Dynamics and diversity of animal production enterprises — G. Alderman (United Kingdom) 91

Management of consumption demand, supply and exchanges — D. Matassino, G. Zucchi & D. di Berardino (Italy) 105

European animal husbandry: a model to adopt or reject by developing countries — H. Jasiorowski (Poland) 127

Synthesis of the 2nd session — J. Coleou, co-chairman (France) 143

Sommaire

Préface — A. Roos (Suède) & J. Coleou (France)

Séance 1 5 "Les acquis scientifiques et techniques des 20 dernières années" Président: R. Février (France); Co-Président: Prof. E.P. Cunningham (Irlande)

Introduction: R. Février, Président (France) 7 Amélioration génétique du cheptel dans les 20 dernières années —

M. Bichard (Grande-Bretagne) 9 Conduite de la reproduction chez les mammifères domestiques: présent et

futur — M. Courot & P. Volland-Nail (France) 23 Les acquis en nutrition et alimentation des 20 denières années — F. de Boer

(Pays-Bas), H. Bickel (Suisse) & N. Todorov (Bulgarie) 39 Conduite des animaux domestiques — A. Neimann-S0rensen (Danemark) 51 Synthèse de la 1ère séance — E.P. Cunningham, Co-Président (Irlande) 63

Séance 2 69 "Les défis et interrogations du futur" Président: A. Roos (Suède); Co-Président: J. Coleou (France)

Gestion du matériel génétique: ajustement à l'évolution économique et aux contraintes de production — F. Pirchner, G. Schömuth & D. Flock (R.F.A) 11

Gestion des ressources alimentaires et conséquences sur la localisation géographique des activités d'élevage — C. Beranger (France) 79

Dynamique et diversité des entreprises de productions animales — G. Alderman (Grande-Bretagne) 91

Gestion de la demande, de l'offre et des échanges — D. Matassino, G. Zucchi &D.di Berardino (Italie) 105

L'élevage européen: un modèle à adapter ou à rejeter pour les pays en développement — H. Jasiorowski (Pologne) 127

Synthèse de la 2ème séance: / . Coleou, Co-Président (France) 143

Inhalt

Vorwort — A. Roos (Schweden) & J. Coleou (Frankreich)

Sitzung 1 "Fortschritt in der Wissenschaft und Technologie während der letzten 20 Jahre" Präsident: R. Février (Frankreich); Co-Präsident: E.P. Cunningham (Irland) 5

Einleitung — R. Février, Präsident (Frankreich) 1 Genetische Verbesserang — M. Bichard (Vereinigtes Königreich) 9 Fortpflanzung — M. Courot & P. Volland-Nail (Frankreich) 23 Ernährung und Fütterung — F. de Boer (Niederlande), H. Bickel (Schweiz) &

N. Todorov (Bulgarien) 39 Strategien in der Entwicklung der Milchproduktion — A. Neimann-S0rensen

(Dänmark) 51 Synthese der le Sitzung — E.P. Cunningham (Irland) 63

Sitzung 2 "Zukünftige Herausforderungen und Fragen" Präsident: A. Roos (Schweden); Co-Präsident: J. Coleou (Frankreich) 69

Handhabung des Tiermaterials: Anpassung an die wirtschaftliche Entwicklung und an produktionsgrenzen — F. Pirchner, G. Schönmuth & D. Flock (Deutschland) 71

Handhabung der Futterbasis und Konsequenzen für die geographische lage der Tierproduktion — C. Beranger (Frankreich) 79

Dynamik und Vielfalt von Tierhaltungen — G. Alderman (Vereinigtes Königreich) 91

Handhabung der Konsumnachfrage, Versorgung und Austausch — D. Matassino, G. Zucchi &D.diBerardino (Italien) 105

Europäische Tierhaltung: ein Modell zur Übernahme oder Ablehnung durch Entwicklungsländer? — H. Jasiorowski (Polen) 127

Synthese der 2er Sitzung — J. Coleou (Frankreich) 143

Foreword

Over the last twenty years, there has been a spectacular development in knowledge of all sectors of animal production. This achievement, which extends to all the various disciplines and species, has undoubtedly formed a wealth of experience which has been developed further through its implementation by producers and at every stage in the various branches of animal production, both upstream and downstream. The annual meetings of the European Association for Animal Production, the various international symposia and colloquia, and the various scientific and technical periodicals and books all testify to the spectacular advance achieved.

Nevertheless, the more techniques progress, the more specializations become exceedingly narrow, with each researcher becoming isolated within his specific field of investigation while the mechanisms appear to be increasingly complex and, at the same time, the phenomena under investigation are increasingly interdependent.

As the twentieth century draws to a close, demographic, political, economic and social de­velopments require that the scientific community as a whole should ponder over what course animal production is to take in this new extended and diverse Europe, lying at the hub of trade flows between the other major continents. • Seek to evaluate and clarify scientific experience; • encourage communication and exchange between specialists in various disciplines and

animal species; • ponder over and respond to the technical, ecological, economic and social challenges of

the third millennium that is awaiting us; those were the three main reasons which led the French Association for Animal Production to propose, initially within the framework of annual meetings, on the occasion of the forty-first meeting organized in Toulouse by the European Association for Animal Production, that a symposium be held bringing together all the various commissions, on the theme:

"On the eve of the third millennium: the European challenge for animal production".

We are particularly indebted to all those persons who have accepted to provide synoptic reports on each of the subjects contained in the programme for this event, in terms both of technical and scientific experience achieved and of the questions raised and future prospects.

May we also thank those who have endeavoured to present, conclude and guide the proceedings of this symposium and express the hope that the conclusions submitted in the summary record will be seen to be the first signs of a solution which animal production could provide to the needs of the European populations in the Mediterranean region and in the developing countries.

A. Roos, President of the European Association for Animal Production

J. Coleou, President of the French Association for Animal Production

Préface

Au cours de ces 20 dernières années, les connaissances dans tous les secteurs des productions animales ont progressé de façon spectaculaire. Tous ces acquis, qui touchent à tous les secteurs disciplinaires et à toutes les espèces, constituent une richesse incontestable qui a fructifié par leur mise en application chez les producteurs et à tous les échelons des filières des produits animaux, de l'amont à l'aval. Les réunions annuelles de la Fédération Européenne de Zoo­technie, les symposiums et colloques internationaux, les revues et ouvrages scientifiques et techniques, etc.. sont là pour témoigner de ces fantastiques avancées.

Mais, plus les techniques progressent, plus les spécialisations se font pointues, isolant les chercheurs chacun dans leur branche alors que les mécanismes apparaissent de plus en plus complexes et que, dans le même temps, les phénomènes sont de plus en plus interdépendants.

Les évolutions démographiques, politiques, économiques et sociales, en cette fin du XXème siècle, imposent à toute la communauté scientifique de s'interroger sur la place de ces productions animales dans cette nouvelle Europe du Nord et du Sud, de l'Est et de l'Ouest, placée au centre des flux d'échanges entre les autres grandes masses continentales. • Evaluer et décanter les acquis scientifiques; • faire se rencontrer et échanger spécialistes de disciplines et d'espèces; • s'interroger et répondre aux défis techniques, écologiques, économiques et sociaux du 3ème

millénaire tout proche; telles étaient les trois principales raisons qui ont poussé l'Associa­tion Française de Zootechnie à proposer, pour la première fois dans le cadre des réunions annuelles, à l'occasion de la 41ème réunion organisée à Toulouse de la Fédération Européenne de Zootechnie, un symposium commun à toutes les commissions, sur le thème:

"A l'orée du troisième millénaire: les défis européens pour les productions animales".

Nous remercions tout particulièrement les personnalités qui ont accepté d'assurer les synthèses sur chacun des sujets mis au programme de cette manifestation, tant en terme d'acquis techniques et scientifiques qu'en terme d'interrogations et de prospectives.

Nos remerciements vont aussi à ceux qui ont tenté d'introduire, conclure et animer les travaux de ce symposium, en espérant que les réflexions présentées dans le présent compte-rendu seront les prémices de réponses que pourront apporter les productions animales aux besoins des populations d'Europe du bassin méditerranéen ainsi que des pays en développe­ment.

A. Roos, Président de la Fédération Européenne de Zootechnie (F.E.Z.)

J. Coleou, Président de l'Association Française de Zootechnie (AdF.Z.)

Vorwort

Im Laufe der letzten zwanzig Jahre haben die Kenntnisse in allen Bereichen der Tierproduktion auf spektakuläre Weise zugenommen. Diese alle Forschungsdisziplinen und Tierarten betref­fenden Errungenschaften stellen durch ihre praktische Anwendung für die Erzeuger wie auch für alle Stufen der Tierproduktion eine unbestreitbare und Früchte tragende Bereicherung dar. Die Jahrestagungen der Europäischen Vereinigung für Tierzucht, die internationalen Sympo­sien und Kolloquien, die technischen und wissenschaftlichen Zeitschriften und Werke etc. legen von diesen Fortschritten Zeugnis ab.

Aber je mehr sich die verschiedenen Techniken entwickeln, desto mehr verschärfen sich die Spezialisierungen und isolieren die einzelnen Forscher in ihren Arbeitsbereichen vonei­nander. Gleichzeitig nimmt die Komplexität der Mechanismen zu, und die einzelnen Phäno­mene befinden sich in immer größerer wechselseitiger Abhängigkeit.

Die am Ende des 20. Jahrhunderts stehenden demographischen, politischen, wirtschaftli­chen und sozialen Entwicklungen stellen die gesamte Forschungsgemeinschaft vor die Not­wendigkeit, sich über den Platz dieser Tierproduktionen in jenem neuen Nord, Süd, Ost und Westeuropa zu befragen, das sich im Mittelpunkt des Austausches zwischen den anderen großen Kontinenten befindet. • Die wissenschaftlichen Errungenschaften abklären und bewerten; • Spezialisten verschiedener Disziplinen und für verschiedene Arten Gelegenheit zum Tref­

fen und Austausch geben; • Fragen stellen und Antworten finden in Bezug auf die technischen, ökologischen, ökono­

mischen und sozialen Herausforderungen des nahenden dritten Jahrtausends dies waren die drei Hauptgründe die die Französische Vereinigung fur Tierzucht dazu veranlaßten, zum ersten Mal im Rahmen ihrer Jahrestagungen der Europäischen Vereinigung für Tierzucht aus Anlaß ihrer 41. Tagung in Toulouse ein für alle Studienkommissionen gemeinsames Symposium mit dem Thema vorzuschlagen:

"Am Vorabend des dritten Jahrtausends: eine Herausforderung für die Tierproduktion in Europa".

Wir danken ganz besonders allen Personen, die sich bereiterklärten, die Synthese eines auf dem Programm dieser Veranstaltung stehenden Themas zu gewährleisten, das die technischen und wissenschaftlichen Errungenschaften oder auch Fragestellungen und Zukunftsorientie­rungen behandelt.

Unser Dank richtet sich auch an diejenigen, die die Arbeiten dieses Symposiums einführten, abschlössen und moderierten. Wir hoffen, daß die in diesem Bericht vorgestellten Überlegun­gen Prämissen für die Antworten sein werden, die die Tierproduktion auf die Bedürfnisse der europäischen Bevölkerungsgruppen des Mittelmeerraums wie auch der Entwicklungsländer zu geben vermag.

A. Roos, Präsident der Europäischen Vereinigung für Tierzucht (E. V.T.)

J. Coleou, Präsident der Französischen Vereinigung für Tierzucht (Association Française de Zootechnie, A.F.Z.)

Session I - Séance I - Sitzung I

Progress in science and technology over the past 20 years

Les acquis scientifiques et techniques des 20 dernières années

Fortschritt in der Wissenschaft und Technologie während der letzten 20 Jahre

Chairman, Président, Präsident: R. Février Co-Chairman, Co-Président, Co-Präsident: E.P. Cunningham

Introduction

Au cours des vingt dernières années, nous avons assisté à un approfondissement considérable de nos connaissances sur la biologie des animaux domestiques. Les techniques de leur exploitation sont devenues plus efficaces; la physionomie de l'élevage européen a été profon­dément modifiée, pendant que l'élevage d'autres pays cherchait sa voie.

L'amélioration génétique, qui avait permis antérieurement d'accroître la productivité des volailles, et des porcs, a continué à progresser pour ces deux espèces. Mais ces deux décennies ont surtout été marquées par l'accroissement de la productivité laitière chez les bovins, où, chaque année, on constate un accroissement de près de 150 kg de lait par lactation; c'est-à-dire de près de 3000 kg pour ces vingt années. Les 4,000 à 5,000 kg qui étaient obtenus naguère dans les bons élevages, sont devenus 7 à 8,000 kg, et les rendements de 12 à 15,000 kg ne sont plus des phénomènes.

En matière de reproduction, à côté de la maîtrise accrue de l'insémination artificielle, la technique des transferts d'embryons est entrée dans la pratique courante, et nous commençons à pouvoir obtenir des jumeaux artificiels, ce qui ouvre des perspectives séduisantes, notamment pour les races bovines à viande qui n'avaient pas connu de modifications spectaculaires dans leur élevage.

Les techniques d'alimentation se sont raffinées, par une meilleure connaissance de la valeur des aliments et des besoins des animaux. L'ajustement des rations à ces besoins permet de nourrir les animaux d'une façon plus économe et moins polluante. Les additifs alimentaires sont utilisés couramment ainsi que d'autres molécules ayant une activité biologique. Ils posent parfois (BST) des problèmes économiques, politiques et de santé.

C'est probablement dans l'alimentation des ruminants que la complexité du processus digestif dans le rumen a suscité le plus d'efforts scientifiques. Les biotechnologies naturelles qui s'y développent peuvent ouvrir des perspectives qui dépassent le seul intérêt zootechnique.

Les systèmes de production ont su intégrer, d'une façon cohérente, ces nouvelles techni­ques, et l'élevage d'aujourd'hui est devenu très différent de l'élevage d'hier. Avec sa produc­tivité accrue d'une façon spectaculaire, il est capable de répondre aux exigences raffinées des consommateurs et de l'industrie (aptitudes fromagères des laits oeufs sans cholestérol).

Les chercheurs et les techniciens qui sont a l'origine de cette évolution peuvent, ajuste titre, être fiers de l'oeuvre accomplie, même si l'on sait que la situation économique a sensible­ment favorisé la mise en oeuvre, dans les élevages, de leurs nouvelles acquisitions scientifi­ques. Il ne faut cependant pas négliger d'autres aspects de cette situation.

D'abord, n'oublions pas que les résultats obtenus pendant ces vingt années sont la consé­quence et le prolongement de l'effort scientifique réalisé souvent dans le silence, au cours des périodes antérieures, et notamment depuis la dernière guerre mondiale. Le développement scientifique suppose une continuité qui ne peut s'accommoder de révisions fréquentes. Les accélérations, comme les pauses, d'aujourd'hui, auront des effets, bons ou néfastes, dans dix ou vingt ans.

Ensuite, notons que les évolutions signalées, ne concernent pas également toutes les espèces animales. Elles ont concerné d'abord les volailles, puis les porcs, récemment les vaches laitières. Les petits ruminants ont été relativement négligés: pourtant ils jouent un rôle eminent dans l'économie agricole et dans l'alimentation de nombreux territoires. C'est là un défi nouveau a relever. Un autre défi concerne d'autres espèces animales qui ont été encore davantage négligées et dont l'exploitation peut élargir les capacités des hommes, pour les différents services qu'ils peuvent en obtenir (équidés, camélidés, cervidés, par exemple).

Mais on peut s'interroger, aussi, sur les différents aspects du bilan de ces deux décennies, mêmes s'il est incontestablement positif. C'est en effet le rôle des chercheurs de remettre inlassablement en cause les idées reçues, même quand ils en sont à l'origine.

L'Europe avait besoin de produire plus de produits animaux. Cet objectif a été globalement atteint, grâce aux nouvelles techniques qui ont souvent fait appel à une consommation accrue d'intrants bon marché, largement compensée par des recettes obtenues grâce au développe­ment des débouchés et à des prix satisfaisants.

Cette situation pourra-t-elle se prolonger? Il est permis d'en douter, puisque les prix sont, au mieux, stabilisés, que la plupart des marchés sont saturés, et que l'approvisionnement à bon marché en intrants d'origine industrielle ou agricole n'est pas assuré. En particulier, pouvon-snous espérer que l'élevage européen pourra éternellement vendre ses produits aux prix euro­péens, et acquérir 60 millions de tonnes d'aliments au prix mondial. Ceci au moment même où on envisage de renoncer aux intrants gratuits, la lumière, la chaleur et les fertilisants naturels, qui alimentent nos propres pâturages.

Cette interrogation économique se double d'une interrogation concernant la pollution dont l'accroissement est directement lié à la concentration des élevages qui sont découplés de ressources fourragères locales. Ainsi, les fertilisants animaux qui avaient été à l'origine de la révolution agricole européenne des XVIIIème et XIXème siècles, deviennent désormais un fardeau qui dresse l'opinion publique contre "nos" nouveaux élevages.

Sans prolonger plus longuement cet examen de conscience qui mériterait d'être plus long, je m'interroge sur l'orientation de l'élevage dans le futur. Nous avons tous, ici été fascinés par les performances de production, parfois même en opposition avec l'opinion conservatrice am­biante. Nous avons souvent rêvé, il y a vingt ans, à la vache à 10,000 kg de lait. Or, aujourd'hui, nous nous interrogeons sur sa rentabilité pour l'éleveur. Nous constatons que son exploitation entraîne une consommation accrue d'aliments concentrés, importés. Nous constatons qu'elle ne produit qu'un veau, et que son exploitation va réduire notre production de viande. Nous constatons qu'elle laisse abandonnés certains territoires de pâturage. En face d'une rentabilité douteuse au niveau individuel, son coût collectif n'est pas contestable.

Ainsi ne devonsnous pas nous intéresser davantage, désormais, aux performances des processus économes de production? De tels objectifs sont à notre portée compte tenu de l'explosion de nos connaissances. Savoir mieux utiliser la cellulose la lignine qui représentent un gisement énorme de matières organiques renouvelables; savoir mieux ajuster la ration azotée aux besoins des animaux, et réduire ainsi de surcroît la pollution des eaux; mieux utiliser la complémentarité de l'élevage et de la forêt méditerranéenne au profit mutuel des deux ; sélectionner des animaux plus résistants aux adversités climatiques et pathologiques, plutôt que d'aménager des bâtiments sophistiqués et de multiplier la distribution de médicaments. Voici quelques pistes, parmi bien d'autres qui pourraient constituer l'amorce d'une sorte de révolution culturelle de l'élevage et plus largement, de l'agriculture.

Cette réflexion rejoint une autre préoccupation: l'élevage dans les pays en voie de dévelop­pement. Doiventils, peuventils imiter les voies de l'élevage européen grâce à ces transferts de technologie qui, en agriculture se sont révélés souvent décevants et coûteux? Les conditions économiques sociales le permettent-elles? ou doiventils rechercher des voies originales, adap­tées à leur situation, comme l'ont fait les Européens ?

Personnellement, je pense qu'ils doivent apporter une attention privilégiée à des techniques adaptées à leurs situations. Dans ce cas, leurs préoccupations pourraient rejoindre celles que j 'ai suggérées pour les Européens puisque les uns et les autres auraient le souci d'un élevage à la fois performant, mais surtout économe.

Ces réflexions anticipent sur le débat de cet aprèsmidi mais on ne pouvait faire le bilan des 20 années écoulées sans évoquer les problèmes qui se posent et les perspectives qui en dé­coulent.

R. Février, Secrétaire général Centre International de Hautes Etudes Agronomiques Méditerranéennes (C.I.H.E.A.M.)

Genetic improvement of livestock over the past 20 years

M. Bichard

Pig Improvement Company, Fyfield Wick, Abingdon, Oxon, 0X13 5NA, United Kingdom

Summary

This paper presents a personal review of strengths and weaknesses of genetic improvement theory and practice over the past 20 years. Animal breeding theory was largely established before this period and so was available for use in all species. Achievements in practice have often been below their potential, particularly in beef cattle and sheep. Some analyses of the reasons are presented as a background to future action. Key words: genetic improvements, livestock breeding programmes, selecting methods.

Résumé

Cette étude analyse ce que je considère être les forces et les faiblesses de la théorie et de l'application du concept de l'évolution génétique durant ces 20 dernières annéel La zootech­nie était déjà bien établie avant cette date et on pouvait donc s'en servir pour toutes les espèces. En réalité, les résultats ont souvent été en deçà de ce qu'on pouvait espérer, surtout pour les boeufs les moutons. Ce document présente une analyse des raisons de cet échec afin d'en tirer des leçons pour l'avenir. Mots clés: évolution génétique, programmes d'élevage, methods de selection.

Introduction

It was not possible to try to review in detail the progress made in each breed, species and country. Many individual reviews have been produced by authors with more specialist knowledge and these were updated at the 4th World Congress of Genetics Applied to Animal Production at Edinburgh in July 1990. Instead this paper attempts to identify the strengths and weaknesses over the past 20 years. The aim is to provoke new reflections about the way ahead. Primary attention will be given to livestock in the countries represented by EAAP, except where lessons can be learned from places further afield.

The review will deal both with the scientific area of animal breeding theory and with its technical implementation into commercial livestock production. It will present a single perspective so the author's background will inevitably show through. His early exposure to practical husbandry of dairy cattle, poultry, goats and sheep was followed by formal training in animal production and animal breeding. This led to academic studies of sheep, poultry and pig improvement through teaching, research and consultancy. For the past 16 years he has held a full-time commercial post involving a combination of technical work in pig improvement in several countries.

Steps in designing a genetic improvement system

A general approach to the steps necessary for the design of efficient animal breeding programmes was set out by Harris et al. (1984).

Step 1. Describe the production system. Step 2. Formulate the objective of the system (this is usefully in the form of a profit function). Step 3. Choose and assemble the lines (breeds) and a crossbreeding system which will

combine them. Step 4. Estimate the genetic parameters in these lines and the necessary environmental effects

and economic weights. Step 5. Design the animal evaluation (testing) system. Step 6. Develop the selection criteria based on those traits which can be measured. Step 7. Design the mating system for selected animals. Step 8. Design the dissemination system. Step 9. Compare alternatives and decide on the overall programme. It is unlikely that any existing improvement programme has been rigorously planned using all these steps; in many cases there has been little choice available and often a new programme evolves out of a previous one. Nevertheless each step requires some decision, if only an acceptance of the status quo.

Genetic improvement in practice

No single person can be equally well informed on progress achieved in all species. Neverthe­less a brief review of the past 20 years is necessary as a background to the conclusions which are drawn in the next section.

Poultry

It is in the several fields of poultry breeding (egg-laying chickens, meat chickens, turkeys and waterfowl) that scientific breeding has found its maximum application. For the reviewer (and teacher) there is a paradox, since much of the work goes on within relatively few competing commercial companies, and specific analyses of their breeding programmes are not often published for impartial study. Almost all countries which have modern egg or poultry-meat production industries are serviced by fewer than 20 specialist breeding companies, already well established by 1970 with trained geneticists using sound genetic principles.

Improvement in meat chickens had been mainly based on growth rate by individual selection with high selection differentials and short generation intervals. Some attention was given to carcass conformation judged simply by handling. Cahaner & Siegel (1986) summarize the industry's success over the previous 50 years as a halving of the time taken to produce a bird at a market weight 50% higher while using one third less feed. Naturally genetics was not the only source of improvement; husbandry, nutrition and disease control also contributed to these dramatic changes. Reduced egg production within the pure-line meat strains caused breeders to change to Fl hybrid parent females in the 1970s. Hybrid parent males were introduced later, in part for better fertility but also to avoid releasing pure-line breeding stock for competitors to pirate. During the 1980s direct selection for feed efficiency commenced. This makes selection programmes much more complicated but is trying to exploit variation not simply associated with reduced maintenance from faster growth to a fixed slaughter weight. Current problems include increasing the proportion of breast meat and processing yield while decreasing abdominal fat.

In egg-laying chickens strain-cross hybrids have also been the dominant type since long before the 1970s. The deliberate production of inbred strains no longer features in commercial programmes. Since egg number is both a sex-limited trait and has low heritability family selection has always been important, either on within-strain performance or strain-cross records. Arthur (1986) expressed doubts that any firms were making full use of the theoretical advantages of optimized statistical indices — combining information from all relatives across

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all traits. His explanation was not that the firms could not tackle such complexities, rather that the available theory was inadequate to cope with the task in a convincing way: economic values are not linear; some trait distributions are not normal; and over-reliance on family means produces unacceptable inbreeding.

Not much selection has been directed at improving disease resistance for several reasons. Resistance may be specific to only one strain of pathogen; measurement may be complex, involving thresholds, and non-genetic solutions (e.g. improved vaccines) may invalidate costly selection efforts. Where official random sample tests have survived, summaries have continued to show annual improvements in hen-housed eggproduction plus other gains in egg weight and feed efficiency. These improvements represent both within-strain changes and between-strain selection as the less successful hybrids are phased out. Emphasis has shifted from just a few major traits to the whole complex of production efficiency and product quality. While rigorous evaluations of progress within individual breeding programmes are not often availa­ble (Smith, 1984) there is no doubt that strong competition has operated. Reduction in the number of primary breeders continues with the successful ones using sound methods and taking risks to survive.

The reasons for the rapid genetic improvement of commercial poultry stocks are worth recording for comparison with the situation in other types of livestock. • A high natural reproductive rate, in both sexes, together with the small size and low financial

value of poultry, means that breeding is comparatively simple and cheap to operate on a statistically adequate scale.

• A short generation interval favours rapid annual progress. , • Commercial poultry production has developed in environments with a high degree of

control (hatching, buildings, nutrition, disease control) and regional or national differences are small.

• Commercial production has been in large specialized units; owners or managers have been relatively sophisticated (technically and financially) and appreciate the value of genetically improved breeding stock.

• Egg production proceeds without the need for males. Hence no offspring are produced at commercial level and there is no temptation to keep back homebred replacements — the market for hybrid replacements is more assured (than in mammalian species).

• Poultry breeders quite soon rejected the concept of the purebred line in favour of synthetic strains, and so have not been held back by conservative forces (herdbook associations, sire licensing etc).

• A lack of subsidy at production level, and a willingness of government and industry organi­zations to get out of breeding, has given free rein to commercial competition driven by market forces.

Pigs

By contrast with the poultry industries, at the beginning of the period under study, pig improve­ment programmes in Europe were almost entirely organized by public bodies and hence their data have been extensively studied.

The Danish national scheme, the model for many others, was based in the 1960s on some 250 separate purebreeding herds. Progeny testing of boars and sows took place through groups sent to central stations. While the annual means of several growth and carcass traits recorded at these stations had shown satisfactory trends the genetic trends were first separated by Smith in 1963 and estimated to be much smaller. Smith followed this up in 1965 with an analysis of British progeny testing results. These revealed that a great deal of testing effort was being very ineffective in creating genetic change. His advice was to limit access to the central stations to a small elite group of herds, and to replace progeny by performance testing. There followed a fundamental review of testing methods throughout Europe.

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Lindhe et al. (1980) stated that "Most countries in Europe are in a situation of rapid transition from the traditional method of progeny testing to more complicated testing programs with combinations of on-farm (performance) testing, station performance testing and progeny testing". The change may have seemed rapid to some—but the theory was set out in Dickerson & Hazel's (1944) classic paper, and already, by 1967, Hetzer & Harvey had shared with the world their results from ten generations of successful selection for and against fat, using a performance test!

Throughout this period there has been a parallel development of genetic improvement and distribution schemes in the private sector. Their programmes were at first open to inspection and at that stage were characterized by simple performance testing of large numbers of both sexes, and rapid generation turnover, rather than by the more accurate methods of predicting breeding value on offer from central test stations in the national schemes. Some companies were undoubtedly started out of frustration with failure of the traditional purebred sector to pick up the new technology being provided by the animal geneticists. Estimates of genetic progress were used by Mitchell et al. (1982) to evaluate the cost effectiveness of these parallel programmes. Groeneveld & Werhahn (1986) later carried out analyses on both herdbook breeders and a cooperative breeding company programme in Germany. In all cases rates of progress were reasonable.

By 1987 the British Meat and Livestock Commission reported that in the 20% of sows recorded in its scheme some 63% of parent gilts and 80% of boars were purchased-from the breeding companies. As a result the national scheme in Britain has now been terminated. The products of company programmes have frequently been .offered in countries other than the original source, so that they already have a major influence on commercial pig improvement throughout Europe. Genetic policies in the largest of these companies were discussed by Bichardetal. (1986).

Nevertheless the surviving nationally organized programmes are improving. Knap (1990), Andersen & Petersen (1990) and Sorensen (1990) have shown how the Dutch and Danish schemes are responding to changing needs and the competition from private breeding com­panies. Prior to the changes to political systems in Eastern Europe in 1989 pig improvement was of course under state control. Schemes in several large state farms in Yugoslavia during the period 1975-84 were analysed by Salehar et al. (1986) who concluded that the genetic changes were in quite good agreement with the phenotypic trends.

In all European countries the trend to fewer breeds has continued through the last 20 years. Dam lines are dominated by Landraces, Large White and some Duroc. Sire lines have concentrated on Pietrain, Belgian Landrace, Hampshire and Duroc. Crossbred parent gilts predominate and some parent boars are also crosses.

Most improvement in commercial pigs has been seen in faster and more efficient liveweight gain, increased carcass lean and improved sow productivity. Nearly all the reasons identified earlier for the rapid improvement in commercial poultry apply also to commercial pigs — though to a lesser degree. Reproductive rate is good, generation interval is often around 18 months, and environmental control is fairly complete. In addition commercial production in some countries is mainly in the hands of specialists who are, at least in Western economies, concerned more with profits than tradition and only lightly protected from the market forces of supply and demand. On the negative side the pure breeding lobby certainly delayed the full exploitation of crossbred gilts and boars in some countries, and even the new EC regulations perpetuate excessive control over 'approved breeding organizations' in order to get agreement on free trade in breeding pigs.

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Dairy cattle

The recent history of dairy cattle improvement shows some distinct differences from that of either poultry orpigs. As long as milk or its components is the selection objective (mea- surable only in the female), and normal reproduction is used, then rates of progress possible by selection within herds of 100 to 200 cows are unattractive. The widespread use of artificial insemination as a cost-effective way of getting commercial cows pregnant in small herds has two vital consequences. First it provides a method of accurately evaluating candidate bulls (through their commercial daughters). Second, it gives an efficient method of spreading the genetic improvement once the superior bulls are identified (proven). In consequence centrally controlled breeding programmes based upon progeny testing young bulls through AI have been an obvious way forward.

AI organizations were already providing a major proportion of total services by the 1970s. Model calculations had explored optimum breeding structures (eJg. Skjervold, 1963) and in­cluded cost considerations (Hinks, 1970). So the stage was set for the application of this techno­logy throughout Europe as in the other dairying countries of the world. Its utilization stimulated an understanding of the weaknesses of the simplest system. Then followed improvements to adjust sire proofs for the merit of their mates and for genetic trend. Progress at commercial level has been measured in many different studies. Van Vleck (1986; 1988) summarized these and found an encouraging trend, with gains approaching nearer to their theoretical predictions after the mid-1970s. He identified longer than necessary generation intervals, undetected prefe­rential treatment of bull dams and 'overemphasis' on traits other than production as probable causes of the shortfall. More recently Meyer & Smith (1990) have shown that previous theo­retical predictions were themselves too high, largely because of a failure to take account of the reduction in genetic variance arising from selection of parents.

In spite of the fact that many of these estimates of genetic progress come from N. American populations they are still very relevant to Europe. Cunningham (1983) described the structure of dairy cattle breeding in W. Europe and emphasized the extent to which breed replacement has proceeded, with Friesian types rising to over 50%, and Simmental and Braunvieh also increasing. But while European dairy fanners have been steadily moving out of local types and replacing them by the major breeds, these in turn have been cashing in on the further genetic advantages of North American strains: Holstein (both black and white and red and white) and Brown Swiss.

Dairy cattle appear to share none of the advantages previously identified as explaining the success of genetic improvement in poultry and pigs. The reasons must lie elsewhere. One big advantage is that there is a single major trait, milk yield, which is easily measured and on which the producer is paid directly. To a large extent, when the dairy farmer opted in favour of AI as a cheap and convenient way of getting his cows pregnant, he simultaneously and perhaps unknowingly put great power over genetic policy into the hands of the AI organiza­tions. While breeders and commercial producers continued to control AI policy they employed professionals who implemented ever-improving programmes of testing and selection. The genetic, statistical and computing problems involved in dealing with many thousands of high-value dairy cows have also attracted some of the best theoretical geneticists. Since frozen semen is easily transported there has also been constant competition from groups in other regions or countries.

Beef cattle

A problem in organizing and evaluating genetic improvement in beef cattle is that much European beef production is inextricably linked with milk production. Many of Europe's dairy cattle have in reality been dual-purpose types, and some are mated to beef bulls to produce crossbred calves. Only in Britain, France and Italy are there substantial populations of beef

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cows. In Britain these are crossbred (usually out of dairy cows by beef bulls) whereas the continental cows are mainly purebred.

The dual-purpose breeds have participated in fairly standard progeny testing programmes (Pirchner, 1986). Changes in beef traits have largely been correlated responses to selection for milk and have not always been favourable. The crossbred populations in Britain have changed somewhat by breed replacement (leaner continental breeds replacing traditional Hereford and Angus) and by changes within the dairy cows (replacement of British Friesian by North Ame­rican Holstein). The purebred continental populations have not in general supported strong genetically based improvement programmes.

The reasons for these problems are not hard to trace. Cattle are inherently slow to improve — with low female reproductive rates and long generation intervals. Some beef characteristics are easily assessed on the live animal (growth and muscling), while others require slaughter or expensive evaluation (meat quality, efficiency) so visual appraisal has persisted. Excessive emphasis on muscling can produce calving difficulties. The dependence of the beef industry on the well-organized dairy industry means that its own objectives get lower priority. For example the dairy farmer sells many dual-purpose calves for beef rearing at an early age before their beef merit can be recognized and rewarded. Nevertheless, some improvement program­mes include initial performance testing before the routine progeny testing for dairy merit. Even then the weight justified on growth and muscling can only expect to slow down the rate of deterioration in beef qualities as a consequence of increasing milk yield. A recent review appears in Simm et al. (1990).

Sheep and goats

Genetic improvement in the world's sheep and goat populations has been very uneven. On the one hand there are pioneering examples of the application of sound genetic principles in small pockets of animals: in Norway, in the dairy sheep of S. France, Italy and Israel. In Australasia the development of open-nucleus schemes, frequently involving groups of breeders, at the beginning of the 1970s has provided an exciting new element in an otherwise rather traditional sector. In spite of these examples the ideas have proved very slow to take root even in the UK, which has the largest sheep population in Europe.

The reviews of Atkins et al. (1986) and Nicoll et al. (1986) are much more a review of the technology waiting to be applied to sheep breeding than a record of achievement in actually creating genetic change. This is in spite of considerable efforts put into recording schemes (Croston et al., 1980) and a huge interest by commercial sheep producers in the type of breeding stock utilized in their flocks. For example large shifts in breed popularity have occurred in Britain between 1971 and 1987 (MLC, 1988).

Some causes of the lack of general application of genetics to sheep and goat improvement are well known. Environmental, technical and economic conditions prevailing in areas where they are kept are frequently difficult. Breeding objectives are not clear, in fact there may often be direct conflicts between adaptation for survival and productivity. Relatively low reproduc­tive rates and long generation intervals do not help. Nevertheless these factors do not entirely explain why, for example, sound breed improvement schemes have not been established in many lowland areas of Britain, and in the terminal sire breeds iji some other countries.

Conclusions

Anyone committed to see genetic improvement occurring at the level of commercial livestock populations must come away from such a review of progress with mixed feelings. On the one hand it is perfectly clear that genetic change can be created and disseminated throughout whole industries and that this can both reduce production costs and improve product quality. On the

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other hand achievements in European animal production have been far below their potential. New methods of manipulating gene frequencies are always emerging. Will these prove to be the key advances which speed up improvement, or will resources devoted to them be wasted because of other impediments to change? In this final review section several conclusions will be drawn out from the earlier reviews.

Existence of adequate genetic theory

It must be accepted that throughout the past 20 years an operationally adequate set of genetic theory has been available to animal breeders. This theory existed not merely as a set of ideas with mathematical proofs but had been shown (Bell, 1974) to function when applied to laboratory animals. Reviews by King (1989) and James (1989) show that additions since 1970 have enhanced rather than fundamentally changed the available methodology. Non-specialists could be persuaded by the enthusiasm of some researchers that genetic improvement really only became possible after the development of best linear unbiased estimation of breeding values in the 1970s — but this is just not true!

Estimating genetic parameters

Estimating genetic parameters has always been a popular occupation of animal geneticists, probably too popular. The unsuitability of many data sets for providing useful estimates has often been ignored. As statisticians have studied this area more thoroughly they .have evolved methods of overcoming the many biases which exist in field data. Simultaneously, computing methods have improved out of all recognition based on remarkable improvements in hardware and software. In addition changes in the size and structure of livestock units and breeding populations have produced much larger data sets. The combined result of all three develop­ments is that today's advanced breeder should have easy access to vastly improved estimates of genetic variances and covariances. In spite, or perhaps because of, the complexity of this subject an army of researchers worldwide is active, and new reviews are frequent. Thompson (1982) and Thompson & Cameron (1986) provided useful summaries.

Need to exploit all methods of genetic change

Animal breeders have to date had three separate methods of changing gene and genotype frequencies in their populations: selection between lines, line crossing and selection within lines. It is important to exploit all three and to use them in the proper sequence. Between-line variation may often be the easiest to utilize.

Within-line improvement is usually slow and can be expensive but is essential for the future. The Danish pig industry was denied all but within-line change since it operated a one-breed policy between 1961 and 1972 (and effectively much earlier also). After the reintroduction of a second damline (Large White) the national herd rapidly changed from purebred Danish Landrace to the use of Fl parent sows, with great benefits in sow productivity, growth rate and feed efficiency. Today's carcasses are frequently three- or four-line crosses (by using Duroc or Duroc x Hampshire sire lines) in order to exploit 'profit-heterosis' to the full (Moav, 1966).

Accuracy of estimation of breeding value

The last 20 years have seen a quiet revolution in thinking (Dempfle, 1989). The efficiency of pig improvement schemes was increased considerably once breeders realised that genetic gain was not simply a function of the accuracy with which candidates' breeding values were estimated. Intensity of selection and generation interval are also relevant. Thus programmes driven by performance testing were adopted in place of those using progeny testing which

15

intuitively seem better because the boars' breeding values are measured directly. While accu­racy continues to increase by the use of more complex models and better computers, Dempfle & Grandi (1988) once again remind breeders of all species that the real goal is to achieve more rapid genetic progress, and this will often be better achieved by testing many candidates with a substantially lower accuracy.

Selection indices

Useful refinement has been brought to selection index theory. While attention has been focused on calculating correct economic weights using appropriate profit functions (Smith et al., 1986), several authors have argued that it may not be possible to use the concept of linear increases in value per unit change in each trait (see Itoh & Yamada, 1987). Schultz (1986) showed exam­ples of non-linear relationships in poultry and suggested that in marketing terms many traits exhibit thresholds beyond which value changes drastically. In practice, poultry breeders use the annual selection exercise to stay very close to their competitors in a number of traits and de Vries (1989) has recently incorporated this concept into a formal index solution. Perhaps the realistic solution is to allow the concept of 'desired gains' to force selection away from the strict economic index solution, but to calculate the apparent losses in efficiency which such indices imply, and be aware of the extent of the conflict.

Effective population size

The different considerations which determine the optimum line size and structure in a selection programme are reasonably well identified. Small proportions of selected males and females leading to a small effective population size will tend to increase rate of genetic change, but also increase its variability so that there is less chance of the actual result being close to that predicted (Nicholas, 1980). A smaller effective line size will give rise to higher inbreeding depression, and will also limit the long-term response both by losing existing useful genes and failing to capture valuable new mutants (Hill, 1985; 1986).

Surely with these conflicting issues there is much more room for tailoring effective line sizes to the specific aims of particular populations? In some current lines there may be too many males in use, so that genetic progress is unnecessarily low; in others there are too few and these are storing up problems for the future. Greater precision in the maintenance of selec­ted lines with predetermined rates of inbreeding should be possible with new theory reviewed by Wray & Thompson (1990).

Quantitative genetics as the framework for animal breeding theory

Those working in animal breeding must try to keep up to date with the offerings from the growth of biotechnology. On the one hand much greater control is being achieved over the reproductive process itself from the maturation of gametes, fertilization and cloning to embryo growth and development. On the other side is the molecular manipulation of the gene itself, its insertion into the developing embryo and the detection of specific genes by probes. By the amount of research funding being put into these areas from both the public and private sector, and by the amount of general interest given to each new result, it might seem that these new disciplines will soon replace conventional improvement methods. It is necessary to repeat that this seems unlikely (Hill & Keightley, 1988). The genetic, statistical and economic framework from which has been built up over the past 50 years must surely remain as the spine discipline of animal breeding. New technology will make its contribution by fitting into this framework and being justified according to its usefulness and cost-effectiveness in comparison with other available solutions.

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Information from specific genetic loci

This is an example of the type of development covered in the previous section. Some recognized loci affect quantitative traits and it is certain that new methods of identification will reveal many more. The framework for considering the benefits of manipulating such loci directly in the selection process was laid out many years ago by Neimann-S0rensen and Robertson (1961) and Smith (1967). The key statistic is the proportion of the additive genetic variance controlled by these known loci relative to the heritability of the trait concerned. If specific loci are going to be of real use then this ratio must be high. Their importance also increases when generation intervals are long and when relatives' information must be utilized because the trait is sex-limited or not measurable on the live candidate. A great deal of effort has been put into trying to discover such loci in the past 20 ears, either quantitative trait loci themselves or marker genes linked to them, in the hope that conventional selection methods might be superseded. There has been a fascination in many laboratories, that such procedures would make the rather mundane procedures of animal improvement more 'scientific'. Many of these endeavours have been misguided. If researchers had understood that genes of large effect would be manipulated quite efficiently by existing crude selection methods, and genes of small effect are very difficult to identify and utilize, then much effort might have been saved. Dempfle & Grundl (1988) also warn of the danger than in the related area, where a physiolo­gical measurement is used to supplement or replace information on the main trait, successful selection may well have serious effects on fitness.

Genetic operations research

This title is used to describe the explanation of the interaction between genetic theory, produc­tion systems and economics. The last 20 years have seen a continued development in the complexity of such studies. Their function is to explore the relative importance of all factors affecting efficiency and profitability in breeding programmes. Naturally the conclusions may depend upon the validity of the model in describing reality, and this can be both complex and dynamic. Nevertheless as results accumulate it becomes possible to see which conclusions are robust over a wide range of assumptions. Studies such as those on dairy cows by Brascamp (1975) and on pigs by de Vries (1989) are already having their impact on actual breeding programmes since those industries are in some places structured in a way which allows them to implement new ideas quite quickly.

It would be helpful if researchers working in this area could spend periods of time in close contact with real breeding programmes, either public or private, in order that their models and the questions they ask of them could be the most relevant.

Appropriate technology for real problems

One of the major reasons why genetic improvement in Europe over the past 20 years has fallen short of its potential is that people have avoided the difficult implementation stage. Two examples are drawn from outside Europe but might just as easily be applied within. Atkins et al. (1986) state "The object of improvement programmes is to return intelligible results on the estimated breeding values of animals (sheep and goats) back to the breeder". Would it not be better if everyone accepted that the real object is to improve the performance and profitability of commercial sheep and goats? At the same conference Schinckel et al. (1986) presented a scheme for the use of a highly sophisticated 'swine testing and evaluation system' to be implemented by national breed associations in the USA. The failure of the US purebred sector to make more efficient genetic improvement has complex causes but very little to do with the breeders' lack of precise estimation technology. In both examples the technology on offer was not sufficient to tackle the real problem.

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Surely all who live by agricultural funds must accept that animal science is an applied subject, and they have some responsibility to provide results which can be applied to real problems? Bichard (1987) has argued for more consideration of structural solutions as one of the ways of solving problems in improvement schemes.

Breeding companies or national programmes

Brascamp (1982) presented an analysis of characteristics of private and public efforts in genetic improvement of pigs, perhaps in an attempt to redress what he saw as unfair criticism of natio­nal programmes. Each analyst starts from a particular background of attitude and experience and it is therefore important to have more than one. In almost all countries there has been in­sufficient motivation to make individual breeders pool their resources and efforts into successful national programmes utilizing modern technology. Exceptions exist where coop­eration is a strong national trait (Scandinavia, Netherlands) or where economic leverage has been available (e.g. cheap AI in dairy cattle). On the other hand competition between strong private breeders of pigs and poultry has undoubtedly transformed commercial production in many parts of Europe in recent years. But private breeders have been unable to make much impact with beef cattle and sheep.

The external view of business is not always very accurate. Smith (1985) pointed out what he saw as a paradox: that breeding companies usually work with several stocks, and often develop specialized lines, while most national improvement schemes select for common objectives in large interbreeding populations. This appears to conflict with the assumption that private breeders can only afford low investment. The argument is that they only stand to gain a fraction of the real national benefit from improvement, their time horizons are short and their risks from competition are high. The fact is of course that successful private ventures learn to balance survival in the short and long term, and breeding companies are used to thinking and planning relatively long time scales. The national scheme, by contrast, as long as it is manipulating the germplasm belonging to individual breeders, finds it difficult to persuade any of them to accept goals different from those which appear best at the time.

Siegel (1988) has analyzed the past successes of poultry breeding companies. He suggests that they will have to adapt to new conditions, for example, manipulate more than just a single trait (e.g. body weight in broilers). While this may be true, the breeders of egg-laying chickens have already demonstrated their ability to succeed with very complex improvement challenges. He reminds them that they have in the past relied heavily on applying the results of publicly-funded research which may reduce in future. Total research efforts are not however diminishing, and breeding companies are quite used to buying their inputs at commercial rates. As a result in-house or contract research or patent rights can all be used if sources of free information dry up.

Dairy cow improvement

The successes of progeny test programmes in dairy cattle populations around the world are well documented. A criticism of European schemes might be that they applied insufficient selection pressure and pursued too similar a selection goal —, so that they were nearly all overtaken by N American programmes. If the new MOET technology (Ruane, 1988) really can deliver equal or greater progress at reasonable cost then the revolution should not be underestimated. It could at last free dairy cow geneticists from their dependence on large cumbersome AI programmes and give them the flexibility previously enjoyed by those with poultry and pig nucleus units. Alternative programmes with different objectives could run side by side, to cope with the inevitable uncertainty of future markets.

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Beef cattle and sheep improvement

There seem to be two quite different routes for effective improvement in these difficult species. One is to try to follow the cooperative way pioneered in Norway and Iceland and tried out on a small scale in Wales and other countries. An enormous effort is needed to understand the culture and problems of the existing flock or herd owners and to design a programme which fits comfortably within their systems. Its genetic content may be low initially, but can grow as confidence develops.

The alternative is to use all the new technology to create improvement and replace the existing breed structure. Early attempts in the UK failed, based on rather little except new syn­thetic lines. Today better scanners for live carcass evaluation, MOET and improved prediction of breeding values might be sufficient to create noticeable improvement. Perhaps some publicly funded pilot projects will be needed before private investment can be attracted.

Quality in livestock products

The last 20 years have largely seen a concentration on increasing output, reducing production costs and making rather simple changes to product quality (reducing fat content of meat). Surplus production and increasing national prosperity are already forcing more attention on other aspects of quality. The concept of quality will embrace many different aspects, including freshness, safety, acceptability of production system as well as the more obvious technological and sensory traits. Genetic manipulation will most certainly have a role in providing increa­singly discriminating customers with milk, fibre, skins and meat products (For example, see Leenstra et al. (1990) for poultry and Sellier (1990) for pigs).

References

Atkins, KD., McGuirk, B.J. & Thompson, R., 1986. Intra-flock genetic improvement program­mes in sheep and goats. Proceedings 3rd World Congress on Genetics Applied to Livestock Production, Lincoln, Nebraska, USA. 9:605-617.

Andersen, S. & Petersen, E.S., 1990. The national breeding programme. Proceedings 4th World Congress on Genetics Applied to Livestock Production, Edinburgh, Scotland, 15:431-4.

Arthur, JA., 1986. An evaluation of industry breeding programs for egg type. Proceedings 3rd World Congress on Genetics Applied to Production, Lincoln, Nebraska, USA. 10:325-336.

Bell, A.E., 1974. Genetic modeling with laboratory animals. Introduction Plenary Session 5. Proceedings 1st World Congress on Genetics Applied to Livestock Production, Madrid, Spain. 1:413-424.

Bichard, M., David, PJ. & Bovey, M., 1986. Selection between and within lines and cross­breeding strategies for worldwide production of hybrids. Proceedings 3rd World Congress on Genetics Applied to Livestock Production, Lincoln, Nebraska, USA. 10:130-142.

Bichard, M., 1987. Problems of across-population genetic evaluation within improvement schemes. Proceedings 6th Conference, Australian Association of Animal Breeding and Genetics, Perth, Australia. 103-111.

Brascamp, E.W., 1975. Model calculations concerning economic optimalization of AI-breed-ing with cattle. Agricultural Research Report 846, Wageningen University, Netherlands, IBSN 9022O-O594-1. 40 pp.

Brascamp, E.W., 1982. Organisation of pig improvement. Proceedings 2nd World Congress on Genetics Applied to Livestock Production, Madrid, Spain. 5:609-615.

Cahaner, A. & Siegel, P.B., 1986. Evaluation of industry breeding programs for meat-type chickens and turkeys. Proceedings 3rd World Congress on Genetics Applied to Livestock Production, Lincoln, Nebraska, USA. 10:337-346.

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Croston, D., Danell, O., Eisen, J.M., Flamant, J.C., Hanrahan, J.P., Jakübec, V, Nitter, G. & Trodahl, S., 1980. A review of sheep recording and evaluation of breeding animals in European countries: a group report. Livestock Production Science 7:373-392.

Cunningham, E.P., 1983. Structure of dairy cattle breeding in Western Europe and comparisons with North America. Journal of Dairy Science 66:1579-1587.

Dempfle, L., 1989. Estimation of breeding values. Eds. Hill, W.G. & Mackay, T.F.C. Evolution and Animal Breeding. CAB International UK. ISBN 0-85198-639-0. 181-188.

Dempfle, L. & Grundl, E., 1988. Identification of superior animals and their use in improve­ment programmes. Advances in animal breeding, Proceedings of the World Symposium in honour of Professor R.D. Politiek, Wageningen, Netherlands. 56-72

de Vries, A.G., 1989a. A method to incorporate competitive position in the breeding goal. Animal Production 48:221-227.

de Vries, A.G., 1989b. Selection for production and reproduction traits in pigs (Selectie op produktie- en reproduktiekenmerken bij varkens). Department of Animal Breeding, Wage­ningen Agricultural University, Netherlands. Doctoral Thesis. 150 pp.

Dickerson, G.E. & Hazel, L.N., 1944. Effectiveness of selection on performance as a supple­ment to earlier culling of livestock. Journal of Agricultural Research 69:459-^476.

Groeneveld, E. & Werhahn, E., 1986. Evaluation of existing industry breeding programs. Herdbook versus cooperative linecrossing program. Proceedings 3rd World Congress on Genetics Applied to Livestock Production, Lincoln, Nebraska, USA. 10:110—118.

Harris, DL., Stewart, T.S. & Arboleda, C.R., 1984. Animal breeding programs: a systematic approach to their design. AAT-NC-8 (Advances in Agricultural Technology, Agricultural Research Service, US Department of Agriculture). 14 pp.

Hetzer, H.O. & Harvey, WJi., 1967. Selection for high and low fatness in swine. Journal of Animal Science 26:1244-1251.

Hill, W.G., 1985. Effects of population size on rates and variability of to short and long term selection. Zeitschrift für Tierzüchtung und Züchtungsbiologie 102:161-173.

Hill, W.G., 1986. Population size and design of breeding programmes. Proceedings 3rd World Congress on Genetics Applied to Livestock Production, Lincoln, Nebraska, USA. 12:245-254.

Hill, W.G. & Keightley, P.D., 1988. Interaction between molecular and quantitative genetics. Advances in animal breeding. Proceedings of the World Symposium in honour of Professor R.D. Politiek, Wageningen. Netherlands. 41-55.

Hinks, CJ.M., 1970. Performance test procedures for meat production amongst dairy bulls used in AI. Animal Production 12:577-583.

Itoh, Y. & Yamada, Y., 1987. Comparisons of selection indices achieving predetermined proportional gains. Genetic Selection and Evolution 19(l):68-82.

James, J.W., 1989. Design of Animal Breeding Programmes. Eds. Hill, W.G. & Mackay, T.F.C. Evolution and Animal Breeding. CAB International UK. ISBN 0-85198-639-0.189-194.

King, J.WJB., 1989. Alan Robertson's contributions to theory and application of animal improvement. Eds. Hill, W.G. & Mackay, T.F.C. Evolution and Animal Breeding. CAB International UK. ISBN 0-85198-639-0. 156-160.

Knap, P. W., 1990. The Herdbook Society/Breed Association. Proceedings 4th World Congress on Genetics Applied to Livestock Production, Edinburgh, Scotland. 15:439-442.

Leenstra, FM. & de Vries, A.W., 1990. Genetic aspects of meat quality in poultry. Proceedings 4th World Congress on Genetics Applied to Livestock Production, Edinburgh, Scotland. 15:531-539.

Lindhe, B., Averdunk, W.G., Brascamp, E.W., Duniec, H., Gaijic, IM., Legault, C, Steane, D.E., 1980. Estimation of breeding value in pigs. Report of a working group of the Commission on Animal Genetics. Livestock Production Science 7:269-282.

McArthur, A.T.G., 1987. Weighting breeding objectives. Proceedings 6th Australian Associa­tion of Animal Breeding and Genetics, Perth, Australia. 179-187.

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Meat and Livestock Commission, 1988. (Meat and Livestock Commission, PO Box 44, Winterhill House, Snowdon Drive, Milton Keynes, MK6 1AX, UK) Sheep in Britain. 36 pp.

Meyer, K. & Smith, C, 1990. Comparison of theoretical and simulated equilibrium genetic response rates with progeny testing in dairy cattle. Animal Production 50:207-212.

Mitchell, G., Smith, C, Makower, M. & Bird, PJ.WJS/., 1982. An economic appraisal of pig improvement in Great Britain. 1. Genetic and production aspects. Animal Production 35:215-224.

Moav, R., 1966. Specialised sire and dam lines. 1. Economic evaluation of crossbreds. 193-202.

Nicholas, F.W., 1980. Size of population for artificial selection. Genetic Research, Cambridge. 35:85-105.

Nicoll, GB., Bodin, L. & Jonmundson, J.V., 1986. Evaluation of inter-flock genetic improve­ment programs for sheep and goats. Proceedings 3rd World Congress on Genetics Applied to Livestock Production, Lincoln, Nebraska, USA. 9:619-636.

Niemann-Sorensen, A. & Robertson, A., 1961. The association between blood groups and several production characters in three Danish cattle breeds. Acta Agriculturae, Scandinavia. 11:163-196.

Pirchner, F. 1986. Evaluation of industry breeding programs for dairy catde milk and meat production. Proceedings 3rd World Congress on Genetics Applied to Livestock Production, Lincoln, Nebraska, USA. 9:153-164.

Ruane, J., 1988. Review of the use of embryo transfer in the genetic improvement of dairy cattle. Animal Breeding Abstracts 56(6):437-446.

Salehar, A., Kovac, M. & Zagozen, F., 1986. Pig improvement schemes for large state farms in Slovenia. Proceedings 3rd World Congress on Genetics Applied to Livestock Production, Lincoln, Nebraska, USA. 10:120-129.

Schinckel, A.P., Harris, D.h., Stewart, T.S. & Lofgren, D.h., 1986. Swine testing and genetic evaluation system for the purebred swine assocations. Proceedings 3rd World Congress on Genetics Applied to Livestock Production, Lincoln, Nebraska, USA. 10:98-109.

Schultz, F.T., 1986. Formulation of breeding objectives for poultry meat production. Proceed­ings 3rd World Congress on Genetics Applied to Livestock Production, Lincoln, Nebraska, USA. 10:215-227.

Sellier, P., 1990. Genetic control of meat quality. Proceedings 41st Annual Meeting of Euro­pean Association for Animal Production, Toulouse, France. Commission on Pig Production. paper P3a.3.

Siegel, PB., 1988. Future breeding programs in poultry. Advances in animal breeding, Proceedings of the World Symposium in honour of Professor R.D. Politiek, Wageningen, Netherlands. 107-115.

Simm, G., Steane,D.E. & Wray,NB., 1990. Developments in beef cattle breeding programmes in Europe. Proceedings 4th World Congress on Genetics Applied to Livestock Production, Edinburgh, Scodand. 15:231-243.

Skjervold, H., 1963. The optimum size of progeny groups and optimum use of young bulls in AI breeding. Acta Agile. Scand. 23:131-140.

Smith, C, 1963. Genetic change of backfat thickness in the Danish Landrace breed of pigs from 1952 to 1960. Animal Production 5(3):259-268.

Smith, C, 1965. Results of pig progeny testing in Great Britain. Animal Production 7(2): 133— 140.

Smith, C, 1967. Improvement of metric traits through specific genetic loci. Animal Production 9(3):349-358.

Smith, C., 1984. Rates of genetic change in farm livestock. Research and Development in Agriculture 79-85

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Smith, C, 1985. Scope for selecting many breeding stocks of possible economic value in the future. Animal Production 41:403-412.

Smith, C, James, J.W. & Brascamp, E.W., 1986. On the derivation of economic weights in livestock improvement. Animal Produciton 43:545-551.

Sfirensen, DA., 1990. An animal model for selection for litter size in the Danish pig breeding program. Proceedings 4th World Congress on Genetics Applied to Livestock Production, Edinburgh, Scotland. 15:435^38.

Thompson, R., 1982. Methods of estimation of genetic parameters. Proceedings 3rd World Congress on Genetics Applied to Livestock Production, Madrid. 5:95-103

Thompson, R. & Cameron, ND., 1986. Estimation of genetic parameters. Proceedings 3rd World Congress on Genetics Applied to Livestock Production, Lincoln, Nebraska, USA. 12:371-381.

van Vleck, L.D., 1986. Evaluation of dairy cattle breeding programs: specialized milk produc­tion. Proceedings 3rd World Congress on Genetics Applied to Livestock Production 9:141-152.

van Vleck, L.D., 1988. Observations on selection advances in dairy cattle. Eds. Weir, B.S., Eisen, E.J., Goodman, M.M. & Namkoong, G. Proceedings 2nd International Conference on quantitative genetics. Sinauer Associates, USA ISBN 0-87893-900-8.433-437.

Wray, N. & Thompson, R., 1990. Advances in selection theory. Proceedings 4th World Congress on Genetics Applied to Livestock Production, Edinburgh, Scotland. 15:5.31-539.

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Management of reproduction in farm animals: present and future

M. Courot & P. Volland-Nail

Station de Physiologie de la Reproduction, Institut National de la Recherche Agronomique, 37380, Nouzilly, France

Summary

Modem techniques applied to reproduction of domestic mammals aim at increasing the efficiency of production of offspring under the conditions of management best suited to the farmers. This report presents the different techniques now available to achieve this objective. For the male, in addition to the use of semen in artificial insemination now possible in all species of farm animals, emphasis will first be on the possibility to deliver a small number of spermatozoa from the best pedigree sires to a maximum number of females with the best chance of fertilization and, second, to keep the males of seasonal breeders (like sheep and goats) permanently at the top of their potential sperm production. For the female, as oestrus and ovulation can now be efficiently controlled, reproduction may be managed in the different species of f arm animals at any chosen period of the year. Sophisticated methods of reproductive technology have also been developed with embryo manipulation in order to further improve the rate of genetic gain. If embryo transfer is now at the stage of commercial development, techniques for in vitro fertilization, sexing and cloning of embryos, as well as gene transfer, are still being developed in research laboratories. These techniques will also be considered in this report as they will certainly change the future of the farm animal industry. Key words: reproduction, cattle, sheep, goats, pigs, horses, sperm production, superovulation, in vitro fertilization, embryo manipulation, cloning, gene transfer.

Résumé

Les techniques modernes de reproduction appliquées aux mammifères domestiques ont pour but d'accroître l'efficacité de la production de jeunes dans les conditions choisies par les éleveurs. Ce rapport présente les différentes techniques disponibles pour atteindre cet objectif. Pour les mâles, en plus de l'utilisation de semence par insémination artificielle désormais possible pour toutes les espèces domestiques, l'accent est mis sur la possibilité d'une part, de distribuer par insémination intrauterine un petit nombre de spermatozoïdes des meilleurs reproducteurs (sur un plan génétique) à un maximum de femelles avec les plus grandes chances de fécondation et, d'autre part, de maintenir les mâles d'espèces saisonnées, telles que les ovins et les caprins, en permanence au maximum de leurs capacités de production spermatique par un régime photopériodique approprié. Pour les femelles, des techniques efficaces de contrôle de l'oestrus et de l'ovulation étant maintenant disponibles dans toutes les espèces domestiques, la reproduction peut être conduite au moment choisi par l'éleveur. Des techniques de repro­duction plus sophistiquées ont été développées avec la manipulation des embryons dans le but de diffuser plus largement le haut potentiel génétique des meilleurs reproducteurs. Si le transfert d'embryons est parvenu à un stade de développement commercial, la fécondation in vitro, les techniques de sexage ou de clonage des embryons sont encore au stade des études de laboratoire. Ces techniques sont néanmoins présentées car elles modifieront certainement la pratique de l'élevage dans les prochaines décennies. En vue d'objectifs peut-être plus

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lointains, la transgenèse est aussi abordée chez les animaux domestiques. Enfin, une brève réflexion prospective évoque plusieurs aspects qui font déjà l'objet de recherches afin de simplifier ou rendre plus efficace encore la reproduction animale. Mots-clés: reproduction; bovin; ovin; caprin; porcin; équin; production de sperme; superovu­lation; fécondation in vitro; manipulation d'embryon; clonage; transfert de gène.

Introduction

The main objective in animal reproduction is to renew generations for a given production purpose, mainly meat, milk or wool according to species or breeds, and, in particular cases, the production of animals of high individual economic importance (for example horse racing). Breeders are looking for the best control of reproduction in both male and female to provide a maximum number of new-born of the required quality at the most appropriate time and at a minimum cost.

During the two last decades, several techniques have been developed for the effective control of reproduction in domestic mammals. For the male, methods of providing permanent availability of semen through the technology of artificial insemination with deep frozen semen are now available for all domestic mammals. Permanent semen production in seasonal bree­ders, such as sheep and goats, can also be obtained by appropriate control of the environment. For the female, methods have been developed for control of the breeding period and increase of the number of offspring per pregnant female through control of ovulation rate, with or without techniques of in vitro fertilization or embryo transfer.

New developments in the control of reproduction are offered by embryo manipulation. Among these new techniques, some are already available, such as blastocyst splitting, while others, such as animal cloning and gene transfer, still belong to the future for production of farm animals.

Semen technology: artificial insemination

Artificial insemination is now a routine technique for animal reproduction under specific con­ditions in many countries. Artificial insemination with deep-frozen semen allows for complete indépendance between male and female reproduction. It is currently used in cattle in most countries where liquid nitrogen is easily available. It is developing for goats since an efficient technology has been proposed for freezing semen (Corteel et al., 1988), but remains fairly limited in sheep and pigs where semen is more difficult to freeze (Sheep: Salamon & Visser, 1972; Colas, 1975. Pigs: Paquignon et al., 1980). However, in these latter species, artificial insemination is largely developed in some countries through use of fresh extended semen either immediately (i.e. less than 12 hours after collection) in oestrus-controlled ewes or, for pigs, under specific herd management systems where semen can be used for up to 3 days after collection with a high rate of pregnancy.

The need for use of large numbers of spermatozoa is a major limiting factor for development of artificial insemination in sheep and it is imperative to reduce these numbers without im­pairing fertility. With available sperm freezing techniques, several authors set out to circum­vent the cervix and to inseminate directly into the uterine cavity where a smaller number of sperm is required to fertilize ova. Since the first experimental surgical uterine inseminations (Trounson & Moore, 1974), it has been established that a small number of spermatozoa (10 to 20xl06) deposited in the uterine cavity through the uterine wall is sufficient for a high rate of pregnancy. High fertility has also been reported following laparoscopic intrauterine inse­mination with fresh semen (Killen & Caffery, 1982). Subsequent experiments and field trials have provided more information on the appropriate time of insemination (48h or even 60h

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after sponge removal) and dose of frozen-thawed semen (at least 20xl06 spermatozoa in the middle of each uterine horn), both factors being dependent on each other (Maxwell, 1986a; 1986b). Intrauterine artificial insemination with a laparoscope is now an efficient technique (55-60% lambing), which can be used under field conditions with frozen semen. It is time consuming, but under well organized technical and practical conditions, it can be an efficient tool for sheep reproduction. In 1988-89, 300,000 ewes were inseminated by this method in Australia, with a significant proportion, 27%, in the stud ewe population (Maxwell & Wilson, 1990).

Promising results have also been obtained in goats using laparoscopic intrauterine insemi­nation with small numbers of spermatozoa.

Permanent semen production in seasonal breeders: photoperiodic control

It has long been known that at high and mid-latitudes, sheep and goats are seasonal breeders with the main period of sexual activity in the autumn. This is related to the amplitude of varia­tion in day length throughout the year (Review: Ortavant et al., 1988). Photoperiodic effects are mediated via the central nervous system which modulates the secretion of gonadotrophic hormones (pulsatility of LH and mean levels of FSH). In turn, these changes in hormonal secretions control the gonads and semen production with a maximum in autumn and a mini­mum in spring.

The length of daylight or photoperiod is the main entraining factor for testicular activity. This is clearly shown in experiments in which the annual variation in the photoperiod is contracted to 8, 6 or even 4 month cycles (Pelletier et al., 1985). Under these conditions, rams and bucks have stimulated gonadotrophic activity and testicular growth during each ' autumnal ' photoperiod, and a rest season during each period of long' days. As the photoperiodic rhythm becomes shorter and reaches 3 or 2 months, the cyclicity of testicular activity is abolished, resulting in constant testicular weights and sperm production at a level similar to that normally seen in the breeding season. The effects of light do not depend on the type of photoperiodic changes, progressive or abrupt, but on the period of the light cycle. With such methods, seasonal rams and bucks can now be transformed into males potentially able to produce semen of high quality and to mate throughout the year (Pelletier et al., 1985; Pelletier & Almeida, 1987; Chemineau et al., 1988; 1989).

Control of the oestrous cycle, induction of ovulation and superovulation

For a better management of reproduction, ovarian cycles of females must be controlled and ovulation induced when needed. Several techniques, such as hormonal treatments, photope­riodic control or the male effect, are now currently used in modern breeding programmes with one main goal;a better planning of work and a more appropriate distribution of parturition.

Recent developments in techniques for in vitro fertilization, embryo transfer and embryo manipulation have created new requirements in this field. Indeed, success of these new tech­niques depends not only on control of the oestrous cycle and ovulation, but also on increased production of oocytes. So, the induction of superovulation in the top females is now a new technical and economical goal.

Control of oestrous cycle and induction of ovulation

Some of the following techniques are currently used in animal husbandry, while others are still new, but already usable.

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Hormonal treatments

Progestagens and/or prostaglandins are in widespread use in domestic mammals for oestrous cycle induction and/or synchronization. Many products are now available for use by farmers (Cattle: Sreenan, 1978. Sheep: Cognié & Mauléon, 1983. Goats: Gonzalez-Stagnaro, 1984. Pigs:Martinat-Bottéetal., 1985. Horses: Driancourt& Palmer, 1982; Webel& Squires, 1982).

Progestagens can be administered by various ways, such as intravaginal sponge pessaries (first developed in sheep by Robinson, 1964), subcutaneous ear implants, injections or addition in feed. Intravaginal devices in silicone elastomer impregnated with progesterone are also used, such as CIDR (Controlled Internal Drug Release) in sheep (Welch, 1983) or PRID (Progesterone Releasing Intravaginal Device) in cattle (Mauer et al., 1975).

Prostaglandins F2oc, as luteolytic agents, are administered by intramuscular injections. A major restriction to the use of prostaglandins F2a is that it can only be used in cyclic females having an active corpus luteum.

Gonadotropins (PMSG or hCG) or gonadotropin releasing hormone are also used widely in domestic mammals to induce ovulation (Short et al., 1988, for a general review. Cattle: Roche et al., 1981. Sheep: Cognié & Mauléon, 1983. Goats: Corteel et al., 1988. Pigs: Day, 1989. Horses: Hyland et al., 1987; Duchamp et al., 1987).

Photoperiod and melatonin

Among domestic mammals, sheep, goats and horses are seasonal breeders for which photo-period is the main environmental cue in the control of reproduction (Review: Ortavant et al., 1985). The use of artificial light for inducing oestrus in ewes (Ortavant et al., 1988, for review), goats (Chemineau et al., 1988) and mares (Palmer et al., 1982) has been extensively studied in the last decades. However, this procedure requires the use of light-proof buildings which are expensive.

An alternative to light-proof buildings has been proposed recently by treatment with melatonin, the hormone which transfers photoperiodic information to the hypothalamo-pitui-tary axis (Review: Arendt, 1986). In the ewe, ithas been demonstrated that melatonin advances seasonal oestrous activity with no undesirable secondary effects upon fertility and, thereby, it can play an essential role in controlled-breeding programmes in sheep-producing countries (Poulton, 1988). Melatonin can be administered by feeding (Kennaway et al., 1982), injection (Nett & Niswender, 1982), infusion (Bittman & Karsch, 1984) or implants (English et al., 1986). In goats, the efficiency of different ways for melatonin administration has also been demonstrated (Chemineau et al., 1988) and it is expected that this will become a new way for the control of goat breeding. In mares, experimental administration of exogenous melatonin also counteracts the effect of long days on the time of first ovulation after ovarian inactivity (Guillaume & Palmer, 1990) and could provide future means for the control of reproduction in equine species.

Male effect

The relationship between the time of introduction of males in'a group of females previously isolated from males and the time of ovulation was first demonstrated in sheep (Underwood et al., 1944). Since that time, the 'ram effect' has been intensively studied (Reviews: Signoret, 1980; Martin et al., 1986). The signal from the rams is partly pheromonal and stimulates breeding activity of ewes by increasing the LH pulse frequency and, as a consequence, growth of follicles. The ram effect is a useful and cheap tool in practical sheep reproduction, but it has limitations due to differences in responsivness of females which depends on breed, season and nutritional status. Similar mechanisms have been described for goats, cattle and pigs.

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Superovulation

The ovulation rate of females can be increased moderately to improve natural prolificacy, or it can be stimulated significantly, i.e. superovulation, to increase the number of high quality oocytes for in vitro fertilization or embryo transfer programmes.

Superovulation is basically achieved with gonadotropins (FSH, PMSG and also hMG) or GnRH, but with great variability in response depending on the individual animals, ovarian activity, breed, season and source of the hormone (Cattle: Saumande, 1987. Sheep: Maxwell et al, 1990. Goats: Amoah & Gelaye, 1990. Pigs: Hammer et al., 1986. Horses: Squires et al., 1986).

Cattle: Various treatments with FSH preparations containing a controlled level of LH, GnRH analogs or bovine follicular fluid have been tested to determine those having the least effect on the normal endocrine profile of the animals (Voss et al., 1989; Gonzalez et al., 1990). PMSG, now called eCG, has limited effects on superovulation of cattle (Saumande, 1987). However when a specific anti-PMSG antibody is used to limit the duration of action of the PMSG, the number of viable embryos per treated cow is similar to that obtained with FSH (Review: Chupin, 1988).

Sheep: The ovulatory response to p-FSH depends on the population of ovarian follicles at the beginning of injections. Pre-treatment with a GNRH agonist, by suppressing large follicles, improves the ovulation rate and reduces its variability (Brebion & Cognié, 1989). The addition of LH to p-FSH in the last injections of a series also increases the ovulation rate of ewes. A combination of PMSG + FSH is also efficient in increasing ovulation rates in'sheep.

Goats: The most widely used gonadotropin preparations are PMSG, in a single injection, and p-FSH, in multiple injections (Review: Amoah & Gelaye, 1990), but, as for cattle, p-FSH tends to adversly alter endocrine profiles.

Horses: Multiple ovulations are not easily obtained in mares where equine pituitary extracts seem to be the most appropriate to stimulate growth of a limited number of follicles (Squires et al., 1986).

Superovulation is thus currently achieved in farm animals with treatments adapted to each species. They can be repeated every 6 to 10 weeks thus increasing total production of ova or embryos per donor female. However an important individual variability in response to hor­monal treatments remains and, with repeated treatments, there is a tendancy for the ovulation rate to decrease possibly due to the formation of antibodies against injected hormones (Beckers etal., 1990).

In vitro fertilization

In vitro fertilization (IVF) is an excellent technique for studying the biological mechanisms of fertilization and early mammalian development. Its applied uses include the multiplication of lines of superior animals, the production of transgenic offspring and the prediction of male fertility. Successful in vitro fertilization has only recently been obtained in domestic animals and the first offspring born following IVF are less than 10 years old in cattle (First references: Brackett et al., 1982; Sicard et al., 1986), 5 years old in sheep (First references: Cheng et al., 1986; Crozet et al., 1987), goats (Hanada, 1985) and pigs (Cheng et al, 1986; Mattioli et al., 1989), and less than 1 year old in horses (Palmer et al., 1990). For success, both ova and sper­matozoa must be properly matured.

Oocytes must be collected by either surgical or laparoscopic routes, or at slaughter. They can be collected at the time of ovulation after in vivo maturation or punctured from ovarian middle-sized follicles before ovulation and matured in vitro in an appropriate medium (Cattle: Leibfried-Rutledge et al., 1989; Marquant-le Guienne et al., 1989. Sheep: Staigmiller & Moor, 1984. Pigs: Moor et al, 1990).

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Semen must be collected from males producing spermatozoa with high fertilizing ability (Cattle: Hillery et al., 1990; Shi et al., 1990. Sheep: Fukui et al., 1988) and properly prepared for IVF (Thibault & Crozet, 1988). In vitro sperm capacitation has been a major problem in domestic animals and many media and technical conditions have been used to achieve this process (Review: First & Parrish, 1988). Efficient media for sperm capacitation must preserve high mobility, facilitate membrane maturation and increase the percentage of sperm under­going spontaneous acrosome reaction (Magistrini & Crozet, 1990). High concentrations of spermatozoa are required to achieve in vitro capacitation which is a long process (6 hours or more for bull and ram sperm), but when it is completed, spermatozoa penetrate the ovum a few minutes after mixing the gametes (Crozet et al., 1987). At an appropriate temperature, a satisfactory medium, sperm concentration and sperm-egg ratio, high rates of fertilization can now be obtained in most farm animals.

Embryo transfer and manipulation

Embryos obtained from in vivo or in vitro fertilized superovulated oocytes must be transplan­ted into recipient females to develop normally until birth. With this complementary technique, it is thus possible to utilize high grade females specifically as donors of oocytes or embryos. These 'genetic mothers' produce large numbers of progeny by repeated superovulation treat­ments while pregnancies are carried out by recipient 'biological mothers'.

Transfer

Depending on species and technical environment, embryo transfer is performed with 5-8 day old embryos either surgically by laparotomy in all species or nonsurgically through the vagina and the cervix in cattle and horses. Laparoscopic procedures were developed recently for small ruminants with 5-7day old embryos (Review: Kraemer, 1989) and improved to be suitable for 1-2 day old sheep embryos (Vallet et al., 1989). Commercial embryo transfer programmes for cattle, sheep and goats indicate that the technique is now available for farmers, but improve­ments are still needed. The success of implantation of transferred embryos might be increased, as shown in cattle, by co-transfer of trophoblastic vesicles and the embryo (Heyman et al., 1987). This is probably due to better communication between the recipient mother and the embryonic material by a more efficient signal from the latter (Martal et al., 1979; Thatcher et al., 1985).

Manipulation

Under specific conditions, embryos may be stored before transfer. They can also be prepared for specific purposes in programmes of genetic improvement.

Freezing

Freezing 6-8 day old embryos has been done routinely in cattle for a long time (Wilmut, 1986). It is possible in sheep and goats and offspring have resulted from transferred frozen-thawed embryos (Willadsen et al., 1976), but only few papers have reported lambing- or kidding-rates exceeding 50% (Heyman et al., 1987; Baril et al., 1989). Freezing of equine and porcine em­bryos is now limited to research laboratories. Freezing younger embryos has not been successfully achieved, but it is possible to obtain in vitro development of fertilized eggs to normal morula or blastocyst stages by co-culture on tubal or uterine epithelial cell monolayers (Review: Rexroad, 1989. Cattle: Eyestone & First, 1989; Marquant-le Guienne et al., 1989.

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Sheep: Gandolfi & Moor, 1987. Goats: Sakkas et al., 1989. Pigs: White et al., 1989. Horses: Battut et al., 1990). These blastocysts could be frozen, but this has not yet been reported.

The development of methods for in vitro culture of embryos not only provides basic information on the biology of early development of mammalian eggs, but it also provides the basis for in vitro screening of embryos for quality. With in vitro culture, one may appreciate the capacity of embryos to survive freezing and thawing, as well as manipulation, like splitting or cloning, and their ability to develop after transfer into recipient females. Such efficient tests are still not available (Review: Butler & Biggers, 1989). In vitro culture of embryos will also be useful in programmes on transgenesis for selecting embryos that have incorporated foreign genes in their genome.

Splitting embryos

All cells derived from the first segmentations after fertilization, until the morula stage, are equipotent to develop into normal embryos. Thus, splitting young embryos has been used in most domestic mammals to increase the number of offspring by doubling the number of embry­os available for transfer (First references: Cattle: Oziletal., 1982; Williams et al., 1982; Sheep: Willadsen, 1979. Goats: Tsunoda et al., 1985. Horses: Allen & Pashen, 1984). Indeed, when pairs of bisected embryos were transferred to each recipient, the overall yield of offspring increased and, under the best conditions, could even exceed 100% (Cattle: Seike et al., 1989. Sheep: Chesne et al., 1987).

Sexing

Since embryos do survive splitting, it is possible to sample a few cells for sexing future off­spring. Any breeder will certainly appreciate the possibility now available to transfer embryos of known sex. Several methods have been used to determine the sex of embryos (Amann, 1989). The most promising is that using DNA-probes specific to the Y-chromosome (Vaiman et al., 1988; Bondioli et al., 1989; Herr et al., 1990; Kirszenbaum et al., 1990). The most recent refinements allow the use of a small number of embryonic cells to which is applied the Poly­merase Chain Reaction (PCR) technique for amplification of DNA specific to the Y-chromo­some. Such specific sequences give a strong hybridization signal with the probe only for male embryos. This method is accurate, rapid and reliable. It will probably be used extensively in the near future.

Sexing techniques can also be applied to spermatozoa, not to separate X and Y spermatozoa but to check the efficiency of methods to separate them which, until now, have proved inopera­tive for domestic animals (Amann, 1989). However, sexing of sperm will become a reality when the technique of sperm flow sorting developed by Johnson et al. (1989) on rabbit sperm will be adapted to other domestic animals.

Animal cloning by nuclear transplantation

The multiplication of superior individuals in a population is important for rapid dissemination of genetic progress. However embryo transfer is not efficient enough to achieve this aim, even when it is associated with repeated superovulation of the top females and splitting embryos to obtain the highest production of embryos. Recent developments in basic knowledge of mammalian embryology suggest new techniques that would permit extensive replication of individuals by way of cloning.

It has been shown that nuclei of cells from the first egg cleavages or even those from the inner cell mass of the early embryo have the capacity to develop into normal embryo when transplanted into a recently ovulated and enucleated oocyte. New-born resulting from embry-

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onic nuclear transplantation have been obtained recently in domestic animals (Catde: Prather etal., 1987;Bondiolietal., 1990. Sheep: Willadsen, 1986; Smith &Wilmut, 1989. Pigs: Prather et al., 1989). These new-born are the result of a series of highly sophisticated techniques of cell micromanipulation such as cellular enucleation and electrofusion. The efficiency of these techniques is limited at present and in need of extensive improvement. It must also be pointed out that, until now, successful animal cloning has been restricted to embryonic totipotent cells and was not possible with cells from adult animals.

Recent refinements have been introduced in the technology of cloning to improve consis­tency and overall efficiency. One may, therefore, be fairly confident in the development of animal cloning for the economy of animal production. It will make an important contribution to genetic gain eventhough cloning does not create new gene associations, but simply produces a series of genetically uniform animals. Indeed, animal cloning will be useful for several reasons: 1) in reducing the lag time between nucleus and commercial level, 2) in increasing the efficiency of evaluation of genetically interesting traits, such as milk production and 3) in investigating interactions between genotype and environmental effects like nutrition, mana­gement or housing. The theoretical genetic response obtained from 'classical' breeding by selection and the use of cloned animals has been compared in dairy cattle.The initial response to selecting parents of clones (obtained by embryo splitting) was equivalent to 4 years of breeding. After 3 years, the progeny of the best clones would be 13 years ahead of an 'artificial insemination population' and a rapid annual genetic change would continue indefinitely (Nicholas & Smith, 1983). Thus, animal cloning will contribute to greater multiplication of genetic progress without any theoretical limitation since it-becomes possible to clone embryos that themselves are derived from nuclear transplantation (Bondioli et al., 1990). However, one must be highly efficient in selecting 'unique' animals to be cloned, having the maximum number of probes to check the clones in order to avoid the risk of diffusing bad genes.

Transgenic animals

Gene transfer cannot be considered as a technique of reproduction per se since it represents manipulation of the egg at the time of fertilization or shortly thereafter (i.e. microinjection of DNA constructs into one of the pronuclei of fertilized eggs or into nuclei of 2 cell embryos), but it seems appropriate to discuss it in this review on modern techniques of reproduction. The advent of recombinant DNA technology made it possible to insert genes into the genome of domestic animals and thus alter their genetic potential. The objective was to introduce a new gene which could change the characteristics of animal performances: genes which control economically important traits such as disease resistance, meat-, milk- or woolproduction. All of us were impressed by the giant mice obtained after insertion of genes for growth hormone at fertilization (Palmiter et al., 1982). It was imagined that similar changes could be obtained in farm animals and several experiments have been carried out in sheep and pigs in an attempt to produce larger animals or to improve carcass quality. This was an optimistic view since the rate of success is very low, about 1/100, and only few transgenic animals have been obtained (Brem et al., 1985; Hammer et al., 1986; Vize et al., 1988; Rexroad et al., 1989). More impor­tantly, inappropriate molecular engineering of these new genes induced adverse physiological effects (Pursel et al., 1990). To be economically efficient, genes need to be correctly targeted and their expression controlled to obtain expected results. At the moment, this is extremely difficult and molecular gene engineering must be developed further before significant success can be obtained in the form of changing animal performance (Pursel et al., 1990; Wilmut et al., 1990). Meanwhile, some success has been recently registered with the production by transgenic ewes of milk containing components of pharmaceutical interest, such as therapeutic human proteins which thus can be produced in large quantities (Wilmut et al., 1990).

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The future

As indicated in this review, several important basic and applied advances in animal reproduc­tion have been made in the last decades. Advanced reproductive technology has already been applied in programmes of genetic improvement of livestock, such as artificial insemination, oestrus control and embryo transfer, eventhough some of them are only moderately efficient as cattle artificial insemination in which conception rates after first services are only around 50-55% in spite of many years of research on semen and artificial insemination technology. Others need more extensive technical advances before being used in animal industry, such as embryo sexing or animal cloning, and their cost benefit must be appreciated before their application becomes widespread.

All of these methods will receive new technological refinement to become more efficient, eventhough natural mating will certainly remain the most common method of animal repro­duction.

In the male, semen freezing requires further technical developments in most species and a reduction in the number of spermatozoa per artificial insemination dose is still an important objective. In the future, one may ask for sexed spermatozoa in all farm animals, the first real success having recently been obtained in rabbits (Johnson et al., 1989). Better preservation of fertilizing ability of sperm in the female tract also represents a challenge for artificial insemi­nation independent of the oestrus period (once at the beginning of the breeding period or once at random every oestrous cycle), making possible the introduction of genetical improvement through 'easy care artificial insemination' under ranching conditions... Any developments in early predictive assessment of reproductive value of males, and of ejaculates, will also be of considerable importance. A more futurist view of artificial insemination is the use of lyophy-lized semen to avoid the heavy and expensive technology of freezing in countries where liquid nitrogen is not easily available. However, the only positive result obtained a long time ago with this technique has never been repeated, even by the authors themselves (Meryman & Kafig, 1963) and no definitive breakthrough has been achieved in this technology.

In the female, besides oestrus control which remains an important applied objective, the low efficiency of oocyte production, either for embryo transfer or for in vitro fertilization or animal cloning, is a major limiting factor for genetic improvement through the female line. Progress in the knowledge of ovarian biology (ovarian follicles and oocytes) will be determi­nant and one can imagine in the next century that the best females will be regularly stimulated to produce a large number of high quality freezable oocytes to be transferred, after fertilization with sexed spermatozoa, or used to produce series of cloned embryos... In order to increase their chances of implantation in recipient mothers, embryos will be transferred (in pairs) with additional trophoblastic vesicles, increasing the embryonic signal for establishment of preg­nancy. Alternatively, mothers could receive injections of interferon recombinant, analogous to trophoblastic protein 1, to increase pregnancy rate. They could also be treated to stimulate early production of pregnancy factors able to reduce embryonic mortality. Some of the clones could also be stored as frozen embryos until results of performance tests are obtained from their twins. Only the best of them would then be allowed to develop and serve to create the future generations...

Conclusion

Coming back to more realistic situations, the different technical aspects of animal reproduction reviewed in this paper show the wide range of possibilities presently available for farmers and technicians to manage farm animal breeding. They can decide when and how to initiate and organize reproduction. The intense economic and technical pressure put on animal production ensures that the best males and females be utilized under the best conditions to create and

31

spread the genetic progress. Most of the reproductive technologies require a more intensive management than simple freerunning farming. They are rather expensive, but all of them can be adjusted to local economic conditions and technical environment in which they might be involved. The ultimate objective is to improve animal production in order to increase the farmers income and the amount of agricultural products needed for nutrition of the rapidly growing human population.

Acknowledgments

The authors wish to thank Prof. F.W. Bazer (Gainsville, Florida, USA), Prof. J. Thimonier (Montpellier, France), Dr. Y. Cognié (Nouzilly, France) and Dr. C. Maxwell (Adelaide, South Australia) for valuable comments and corrections of the manuscript.

References

Allen, W.R. & Pashen, RL. 1984. Production of monozygotic (identical) horse twins by embryo micromanipulation. Journal of Reproduction and Fertility 71:607-613.

Amann, R.P., 1989. Treatment of sperm to predetermine sex. Theriogenology 31:49-60. Amoah, E.A. & Gelaye, S., 1990. Superovulation, synchronization and breeding of does. Small

Ruminant Research 3:63-72. Arendt, J., 1986. Role of the pineal gland and melatonin in seasonal reproductive function in

mammals. Oxford Reviews of Reproductive Biology 8:266-320. Baril, B„ Casamitjana, P., Perrin, J. & Vallet, J.C., 1989. Embryo production, freezing and

transfer in Angora, Alpine and Saanen goats. Züchthygiene 24:101-115. Battut, I., Bézard, J. & Palmer, E., 1990. Establishment of equine oviduct cell monolayers, for

coculture with early equine embryos. 5th International Symposium on Equine Reproduc­tion, 1-7 July 1990, Deauville (France). Journal of Reproduction and Fertility, Suppl. 44: In press.

Beckers, J.F., Baril, G., Vallet, J.C., Chupin, D., Remy, B. & Saumande, J., 1990. Are porcine follicle stimulating hormone antibodies associated with decreased superovulatory response in goat? Theriogenology 33:192.

Bittman, EL. & Karsch, F.J., 1984. Nightly duration of pineal melatonin secretion determines the reproductive response to inhibitory daylength in the ewe. Biology of Reproduction 30:585-593.

Bondioli, K.R., Ellis, S.B., Pryor, J.H., Williams, M.W. & Harpold, MM., 1989. The use of male-specific chromosomal DNA fragments to determine the sex of bovine pre-implanta-tion embryos. Theriogenology 31:95-104.

Bondioli, K.R., Westhusin, M.E. & Looney, CM., 1990. Production of identical bovine off­spring by nuclear transfer. Theriogenology 33:165-174.

Brackett, B.G., Bousquet, D., Boice, ML., Donawick, W.J., Evans, J.F. & Dressel, M.A., 1982. Normal development following in vitro fertilization in the cow. Biology of Reproduction 27:147-158.

Brebion, P. & Cognié, Y., 1989. Increased superovulation in the ewe following 14 days of Gn-RH agonist pre-treatment. 5ème Réunion de l'Association Européenne de Transfert Embryonnaire, 8-9 Septembre 1989, Lyon (France). Abstract 106.

Brem, G., Brenig, B., Goodman, H.M., Seiden, R.C., Graf, F., Kruff, B., Springman, K., Hondele, J., Meyer, J., Winnacker, EL. & Kräusslich, H., 1985. Production of transgenic mice, rabbits and pigs by microinjection into pronuclei. Züchthygiene 20:251-252.

Butler, J.E. & Biggers, JD., 1989. Assessing the viability of preimplantation embryos in vitro. Theriogenology 31:115-126.

32

Chemineau, P., Pelletier, J., Guérin, Y., Colas, G., Ravault, J.P., Toure, G., Almeida, G., Thimonier, J. & Ortavant, R., 1988. Photoperiodic and melatonin treatments for the control of seasonal reproduction in sheep and goats. Reproduction, Nutrition, Développement 28: 409-422.

Chemineau, P., Delgadillo, JA., Malpaux, B. & Pelletier, J., 1989. Annual clock and control of domestic mammal reproduction. In: M. Serio (Ed.): Perspectives in Andrology. Raven Press, New-York. Serono Symposia 55:307-315.

Cheng, W.T.K., Moor, R.M. & Polge, C, 1986. In vitro fertilization of pig and sheep oocytes matured in vivo and in vitro. Theriogenology 25:146.

Chesne, P., Colas, G., Cognié, Y., Guérin, Y. & Sevellec, C, 1987. Lamb production using superovulation, embryo bisection, and transfer. Theriogenology 27:751-757.

Chupin, D., 1988. Superovulation par PMSG ou FSH pour le transfert embryonnaire. In: Les hormones et leurs analogues dans la reproduction. Pharmacologie et pharmacocinétique. Masson, Paris. Colloque de la Société Française pour l'Etude de la Fertilité 26:213-232.

Cognié, Y. & Mauléon, P., 1983. Control of reproduction in the ewe. In: W. Haresign (Ed.): Sheep production. Butterworths, London, p. 381-392.

Colas, G., 1975. Effect of initial freezing temperature, addition of glycerol and dilution on the survival and fertilizing ability of deep-frozen ram semen. Journal of Reproduction and Fertility 42:277-285.

Corteel, J.M., Leboeuf,B. & Baril, G., 1988. Artificial breeding of adult goats and kids induced with hormones to ovulate outside the breeding season. Small Ruminant Research 1:19-35.

Crozet, N., Huneau, D., Desmedt, V, Theron, M.C., Szollosi, D., Torres, S. & Sevellec, C, 1987. In vitro fertilization with normal development in the sheep. Gamete Research 16: 159-170.

Day, BJV., 1989. Control of estrus and ovulation in swine. Agri-Practice 10:11-15. Driancourt, MA.& Palmer, E.,1982. Seasonal and individual effects on ovarian and endocrine

responses of mares to a synchronization treatment with progestagen-impregnated vaginal sponges. Journal of Reproduction and Fertility, Suppl. 32:283-291.

Duchamp, G., Bour, B., Combarnous, Y. & Palmer, E., 1987. Alternative solutions to hCG induction of ovulation in the mare. Journal of Reproduction and Fertility, Suppl. 35:221-228.

English, J., Poulton, AL., Arendt, J. & Symons, A.M., 1986. A comparison of the efficiency of melatonin treatments in advancing oestrus in ewes. Journal of Reproduction and Fertility 77:321-327.

Eyestone, W.H. & First, N.L., 1989. Co-culture of early cattle embryos to the blastocyst stage with oviducal tissue or in conditioned medium. Journal of Reproduction and Fertility 85: 715-720.

First, N.L. & Parrish, J.J., 1988. Sperm maturation and in vitro fertilization. 11th International Congress on Animal Reproduction and Artificial Insemination, 26-30 June 1988, Dublin (Ireland). Vol. 5, p. 161-168.

Fukui, Y., Glew, A.M., Gandolfi, F. & Moor,R.M., 1988. Ram-specific effects on in-vitro fertili­zation and cleavage of sheep oocytes matured in vitro. Journal of Reproduction and Fertility 82:337-340.

Gandolfi, F. & Moor, R.M., 1987. Stimulation of early embryonic development in the sheep by co-culture with oviductal epithelial cells. Journal of Reproduction and Fertility 81:23— 28.

Gonzalez, A., Lussier, J.G., Carruthers, T.D., Murphy, BD. & Mapletofi, R.J., 1990. Supero­vulation of beef heifers with folltropin: A new FSH preparation containing reduced LH activity. Theriogenology 33:519-529.

33

Gonzalez-Stagnaro, C, 1984. Control hormonal del ciclo estrual en pequenos rumiantes del area tropical. In: Chemineau, P., Gauthier, D. & Thimonier, J. (Eds): Reproduction des ruminants en zone tropicale. Les Colloques de 1'INRA, N20. INRA (Paris). 8-10 Juin 1983, Pointe-à-Pitre (Guadeloupe), p. 433-471.

Guillaume, D. & Palmer, E., 1990. Effect of oral melatonin on the date of the first ovulation after ovarian inactivity of mares under artificial photoperiod. 5th International Symposium on Equine Reproduction, 1-7 July 1990, Deauville (France). Journal of Reproduction and Fertility, Suppl.44: In press.

Hammer, R.E., Pursel, V.G., Rexroad, CE., Wall, R.J., Bolt, DJ., Palmiter, RD. & Brinster, RL., 1986. Genetic engineering of mammalian embryos. Journal of Animal Science 63: 269-278.

Hanada, A., 1985. In vitro fertilization in goats (in Japanese). Japanese Journal of Animal Reproduction 31:21-26.

Herr, CM., Matthaei, KJ., Bradley, M.P. & Reed, K.C., 1990. Rapid acurate sexing of livestock embryos. Proc. 4th World Congress on Genetics Applied to Livestock Production, 23-27 July 1990, Edinburgh (UK). Vol. 16:334-343.

Heyman, Y., Vincent, C, Gamier, V. & Cognié, Y., 1987. Transfer of frozen-thawed embryos in sheep. Veterinary Record 120:83-85.

Hillery, F.L., Parrish, J J. & First, NL., 1990. Bull specific effect on fertilization and embryo development in vitro. Theriogenology 33:249.

Hyland, J.H., Wright, P.J., Clarke, I.J., Carson, R.S., Langsford, DA. & Jeffcott, LB., 1987. Infusion of gonadotrophin-releasing hormone (GnRH) induces ovulation and fertile oestrus in mares during seasonal anoestrus. Journal of Reproduction and Fertility, Suppl. 35:211-220.

Johnson, LA., Flook, J.P. & Hawk, H.W., 1989. Sex preselection in rabbits: Live births from X and Y sperm separated by DNA and cell sorting. Biology of Reproduction 41:199-203.

Kennaway, DJ., Gilmore, TA. & Seamark, R.F., 1982. Effect of melatonin feeding on serum prolactin and gonadotropin levels and the onset of seasonal estrous cyclicity in sheep. Endocrinology 110:1766-1772.

Killen, ID. & Caffery, G J., 1982. Uterine insemination of ewes with the aid of a laparoscope. Australian Veterinary Journal 59:95.

Kirszenbaum, M., Cotinot, C, Leonard, M., Vaiman, M. & Fellous, M., 1990. Diagnostic du sexe des embryons bovins par biologie moléculaire. Reproduction, Nutrition, Develop­ment, Suppl. l:125s-132s.

Kraemer, D.C., 1989. Embryo collection and transfer in small ruminants. Theriogenology 31: 141-148.

Leibfried-Rutledge, ML., Critser, E.S., Parrish, JJ. & First, N.L., 1989. In vitro maturation and fertilization of bovine oocytes. Theriogenology 31:61-74.

Magistrini, M. & Crozet, N., 1990. Capacitation et réaction acrosomique chez les animaux do­mestiques. Contraception, Fertilité, Sexualité 18:795-789.

Marquant-le Guienne, B., Gérard, M., Solari, A. & Thibault, C, 1989. In vitro culture of bo­vine egg fertilized either in vivo or in vitro. Reproduction, Nutrition, Development 29: 559-568.

Martal, J., Lacroix, M.C, Loudes, M.C., Saunier, M. & Wintenberger-Torrès, S., 1979. Tropho­blastin, an antiluteolytic protein present in early pregnancy in sheep. Journal of Reproduc­tion and Fertility 56:63-73.

Martin, G.B., Oldham, CM., Cognié, Y. & Pearce, D.T., 1986. The physiological responses of anovulatory ewes to the introduction of rams. A review. Livestock Production Science 15:219-247.

Martinat-Botté, F., Bariteau, F., Badouard, B. & Terqui, M., 1985. Control of pig reproduction in a breeding programme. Journal of Reproduction and Fertility, Suppl. 33:211-228.

34

Mattioli, M., Bacci, ML., Galeati, G. & Seren E., 1989. Developmental competence of pig oocytes matured and fertilized in vitro. Theriogenology 31:1201-1207.

Mauer, R.E., Webel, S.K. & Brown, M.D., 1975. Ovulation control in cattle with progesterone intravaginal device (PRID) and gonadotropin releasing hormone (GnRH). Annales de Biologie Animale, Biochimie, Biophysique 15:291-296.

Maxwell, W.M.C., 1986a. Artificial insemination of ewes with frozen-thawed semen at a syn­chronised oestrus. 1. Effect of time of onset of oestrus, ovulation and insemination on ferti­lity. Animal Reproduction Science 10:301-308.

Maxwell, W.M.C., 1986b. Artificial insemination of ewes with frozen-thawed semen at a syn­chronised oestrus. 2. Effect of dose of spermatozoa and site of intrauterine insemination on fertility. Animal Reproduction Science 10:309-316.

Maxwell, W.M.C. & Wilson, HM., 1990. Systems of sheep breeding in Australia. World Merino Conference, 2-4 May 1990, Pretoria (South Africa). Vol. 1, Section 4 (3), p. 1-15.

Maxwell, W.M.C, Szell, A., Hunton, JR. & Ryan, J.P., 1990. Artificial breeding: Embryo transfer and cloning. Symposium on "Reproductive physiology of Merino sheep. Concepts and consequences". 27-29 September 1990, Australia.

Meryman, H.T. & Kafig, E., 1963. Freeze-drying of bovine spermatozoa. Journal of Repro­duction and Fertility 5:87-94.

Moor, R.M., Mattioli, M., Ding, J. & Nagai, T., 1990. Maturation of pig oocytes in vivo and in vitro. Journal of Reproduction and Fertility, Suppl. 40:197-210.

Nicholas, F.W. & Smith, C., 1983. Increased rates of genetic change in dairy cattle by embryo transfer and splitting. Animal Production 36:341-353. /

Nett, T.M. & Niswender, G.D., 1982. Influence of exogenous melatonin on seasonality of repro­duction in sheep. Theriogenology 17:645-653.

Ortavant, R., Pelletier, J., Ravault, J.P., Thimonier, J. & Volland-Nail, P., 1985. Photoperiod: main proximal and distal factor of the circannual cycle of reproduction in farm mammals. Oxford Reviews of Reproductive Biology 7:305-345.

Ortavant, R., Bocquier, F., Pelletier, J., Ravault, J.P., Thimonier, J. & Volland-Nail, P., 1988. Seasonality of reproduction in sheep and its control by photoperiod. Australian Journal of Biological Sciences 41:69-85.

Ozil, J.P., Heyman, Y. & Renard, J.P., 1982. Production of monozygotic twins by micromani­pulation and cervical transfer in the cow. Veterinary Record 110:126-127.

Palmer, E., Driancourt, MA. & Ortavant, R., 1982. Photoperiodic stimulation of the mare during winter anoestrus. Journal of Reproduction and Fertility, Suppl. 32:275-282.

Palmer, E., Beiard, J., Magistrini, M. & Duchamp, G., 1990. Invitro fertilisation in the horse: A retrospective study. 5th International Symposium on Equine Reproduction, 1-7 July 1990, Deauville (France). Journal of Reproduction and Fertility, Suppl. 44: In press.

Palmiter, RD., Brinster, R.L., Hammer, R.E., Trumbauer, M.E., Rosenfeld, M.G., Birnberg, N.C. & Evans, R.M., 1982. Dramatic growth of mice that develop from eggs microinjected with metallothionein-growth hormone fusion genes. Nature 300:611-615.

Paquignon, M., Bussière, J., Bariteau, F. & Courot, M., 1980. Effect of frozen boar semen under practical conditions of artificial insemination. Theriogenology 14:217-226.

Pelletier, J., Brieu, V., Chesneau, D., Pisselet, C. & De Reviers, M.M., 1985. Abolition partielle des variations saisonnières du poids testiculaire chez le bélier par diminution de la période du cycle lumineux. Comptes Rendus de l'Académie des Sciences, Paris. 301:665-668.

Pelletier, J. & Almeida, G., 1987. Short light cycles induce persistent reproductive activity in Ile-de-France rams. Journal of Reproduction and Fertility, Suppl. 34:215-226.

Poulton, AL., 1988. The proposed use of melatonin in controlled sheep breeding. Australian Journal of Biological Sciences 41:87-96.

Prather, R.S., Barnes, FL., Sims, MM., Robl, J.M., Eyestone, W.H. & First, N.L., 1987. Nuclear transplantation in the bovine embryo: Assessment of donor nuclei and recipient oocyte. Biology of Reproduction 37:859-866.

35

Prather, R.S., Sims, M.M. & First, N.L., 1989. Nuclear transplantation in early pig embryos. Biology of Reproduction 41:414-418.

Pursel, V.G., Bolt, DJ., Miller, K.F., Pinken, CA., Hammer, R.E., Palmiter, RD. & Brinster, RL., 1990. Expression and performance in transgenic pigs. Journal of Reproduction and Fertility, Suppl. 40:235-245.

Rexroad, CE., 1989. Co-culture of domestic animal embryos. Theriogenology 31:105-114. Rexroad, C.E., Hammer, R.E., Bolt, DJ., Mayo, K.E., Frohman, LA., Palmiter, RD. &

Brinster, RL., 1989. Production of transgenic sheep with growth-regulating genes. Mole­cular Reproduction and Development 1:164-169.

Robinson, TJ., 1964. Synchronization of oestrus in sheep by intravaginal and subcutaneous application of progestin impregnated sponges. Proceeding of the Australian Society of Ani­mal Production 8:47-49.

Roche, J.F., Ireland, J. & Mawhinney, S., 1981. Control and induction of ovulation in cattle. Journal of Reproduction and Fertility, Suppl. 30:211-222.

Sakkas, D., Ban, P.A. & Cameron, A.W.N., 1989. Development of preimplantation goat (Capra hircus) embryos in vivo and in vitro. Journal of Reproduction and Fertility 87:359-365.

Salomon, S. & Visser, D., 1972. Effect of composition of Tris-based diluent and of thawing solution on survival of ram spermatozoa frozen by the pellet method. Australian Journal of Biological Science 25:605-618.

Saumande, J., 1987. Superovulation chez les bovins: Actualités et perspectives. 3èrne Collo­que de l'Association Européenne de Transfert Embryonnaire, 4-5 Septembre 1987, Lyon (France), p. 97-117.

Seike, N., Saeki, K., Utaka, K., Sakai, M., Takakura, R., Nagao, Y. & Kanagawa, H., 1989. Production of bovine identical twins via transfer of demi-embryos without zonae pelluci-dae. Theriogenology 32:211-220.

Shi, D.S., Lu, K.H. & Gordon I., 1990. Effects of bulls on fertilization of bovine oocytes and their subsequent development in vitro. Theriogenology 33:324.

Short, R.E., Staigmiller,RB. & Bellows, RA., 1988. Hormonal treatments to induce ovulation. 11th International Congress on Animal Reproduction and Artificial Insemination, 26-30 June 1988, Dublin (Ireland). Vol. 5:146-154.

Sicard, M.A., Lambert, R.D., Ménard, D.P. & Beyoda, M., 1986. In vitro fertilization in the cow: 6 calves are born from surgical and non-surgical uterine transfer to heifers. Therioge­nology 25:198.

Signoret, J.P., 1980. Effet de la présence du mâle sur les mécanismes de reproduction de la femelle des mammifères. Reproduction, Nutrition, Développement 20:1457-1468.

Smith, L.C. & Wilmut, L, 1989. Influence of nuclear and cytoplasmic activity on the develop­ment in vivo of sheep embryos after nuclear transplantation. Biology of Reproduction 40:1027-1035.

Squires, EL., Garcia, R.H., Ginther, O J., Voss, JL. & Seidel, G.E., 1986. Comparison of equine pituitary extract and follicle stimulating hormone for superovulating mares. Therio­genology 26:661-670.

Sreenan, J.M., 1978. Control of reproduction in the cow. Martinus Nijhoff, The Hague. Staigmiller, RB. & Moor, R.M., 1984. Effect of follicle cells on the maturation and develop­

mental competence of ovine oocytes matured outside the follicle. Gamete Research 9: 221-229.

Thatcher, W.W., Knickerbocker, J J., Bartol, F.F., Bazer, F.W., Roberts,R.M. & Drost, M., 1985. Maternal recognition of pregnancy in relation to the survival of transferred embryos: endocrine aspects. Theriogenology 23:129-143.

Thibault, C. & Crozet, N., 1988. La fécondation in vitro des ovocytes de brebis et de vache peut-elle entrer dans la pratique de l'élevage? 3rd World Congress on Sheep and Beef Cattle Breeding, 19-23 Juin 1988, Paris (France). Vol. 1:79-91.

36

Trounson, A.O. & Moore, N.W., 1974. Fertilization in the ewe following multiple ovulation and uterine insemination. Australian Journal of Biological Science 27:301-304.

Tsunoda, Y., Tokunaga, T., Sugie, T. & Katsumata, M., 1985. Production of monozygotic twins following the transfer of bisected embryos in the goats. Theriogenology 24:337-343.

Underwood, E.J., Shier, FL. & Davenport, N., 1944. Studies in sheep husbandry in Western Australia. 5. The breeding season of Merino crossbred and British breed ewes in the agri­cultural districts. Journal of Agriculture (Western Australia) 11:135-143.

Vaiman, M., Cotinot, C, Kirszenbaum, M., Leonard, M., Chesné, P., Heyman, Y., Stinnakre, M.G., Bishop, C. & Fellous, M., 1988. Sexing of bovine embryos using male-specific nucleic acid probes. 3rd World Congress on Sheep and Beef Cattle Breeding, 19-23 Juin 1988, Paris (France). Vol.l:93-105.

Vallet, J.C., Folch, J., Poulin, N. & Cognié, Y., 1989. Surgical or laparoscopic embryo transfer in sheep before or after the first cleavages. 5ème Réunion de l'Association Européenne de Transfert Embryonnaire, 8-9 Septembre 1989, Lyon (France). Abstract p. 188.

Vize, PD., Michalska, A.E., Ashman, R., Lloyd, B., Stone, B.A., Quinn, P., Wells, J.R.E. & Seamark, R.F., 1988. Introduction of a porcine growth hormone fusion gene into transgenic pigs promotes growth. Journal of Cell Science 90:295-300.

Voss, HJ., Allen, S.E., Foote, R.H., Im, P., Kim, CK. & Aquadro, P., 1989. Buserelin in a su-perovulatory regimen for Holstein cows. 1. Pituitary and ovarian hormone response in an experimental herd. Theriogenology 31:371-384.

Webel, S.K. & Squires, EL., 1982. Control of the oestrous cycle in mares with altrenogest. Journal of Reproduction and Fertility, Suppl. 32:193-198.

Welch, R.A.S., 1983. Drug delivery in agricultural animals. Proceedings of the 26th Annual Meeting of the Endocrine Society of Australia, Vol. 26 (Suppl. 2), p. 46.

White, KL., Hehnke, K., Rickords, L.F., Southern, LL., Thompson, DL. & Wood, T.C., 1989. Early embryonic development in vitro by coculture with oviductal epithelial cells in pigs. Biology of Reproduction 41:425-430.

Willadsen, SM., Polge, C, Rowson, L.EA. & Moor, R.M., 1976. Deep freezing of sheep embryos. Journal of Reproduction and Fertility 46:151-154.

Willadsen, S.M., 1979. A method for culture of micromanipulated sheep embryos and its use to produce monozygotic twins. Nature 277:298-300.

Willadsen, S.M., 1986. Nuclear transplantation in sheep embryos. Nature 320:63-65. Williams, T.J., Eisden, R.P., Seidel, G.E., 1982. Identical twin bovine pregnancies derived from

bisected embryos. Theriogenology 17:114. Wilmut, I., 1986. Cryopreservation of mammalian eggs and embryos. In: Gwatkin, R.B.L.

(Ed.): Developmental biology. Vol. 4. Manipulation of mammalian development. Plenum Press, New-York. p. 217-247.

Wilmut, I., Archibald, AL., Harris, S., McClenaghan, M., Simons, J.P., Whitelaw, C.B.A. & Clark, A J., 1990. Methods of gene transfer and their potential use to modify milk com­position. Theriogenology 33:113-123.

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Progress in nutrition and feeding over the past 20 years

F. de Boer*, H. Bickel** & N. Todorov***

* IWO, Lelystad, NL ** ETH Zurich, CH *** IZVM, Stara Zagora, BG

Summary

Research on feeding and nutrition of livestock has been always a spinoff from progress or trends in science and society, economy included. In the last twenty years, the combined effect of both has resulted in substantial progress • in well founded evaluation systems of energy and protein in feedstuff s in combination with

strongly increasing international consistency • in knowledge of the quality of forages, cereals, other seeds and by-products of vegetable

and of animal origin. Together with progress in other production tools, such as breeding techniques, housing, mechanization this has led to livestock production systems, which have raised concern in so­ciety. This phenomenon has stimulated progress in feeding and nutrition and'new scientific tools have been developed • to reduce the risk of carry-over of unwanted contaminants or residues from feed for animals

to food for humans • to reduce the risk of continued environmental polluting effects of inorganic feed compo­

nents, such as nitrogen, phosphorus and other minerals. In recent years, progress in other scientific disciplines has affected feeding and nutrition substantially. Examples are the greatly increased knowledge of rumen fermentation, of protein and amino acids metabolism, of analysis equipment, of biotechnology, of genetic manipulation and others. Strongly stimulated by sophisticated computer technology, this had led to increased interdisciplinary research with favourable effects for the future of livestock production and for society as well.

Résumé

Durant les 20 dernières années, le progrès substantiel des connaissances en physiologie de la nutrition des animaux domestiques (de rente) créait de nouvelles conceptions relatives à l'évaluation des valeurs nutritives des aliments et à l'alimentation. L'ancien concept de Kellner (1908) notamment, consistant à exprimer la valeur des aliments par leur capacité à produire de la graisse animale, était déjà critiqué il y a 50 ans et nullement accepté universellement. Stimulé par de nouvelles notions concernant le métabolisme énergétique des ruminants princi­palement, de nouveaux systèmes d'évaluation énergétique étaient proposés, compilés par Van der Honing & Alderman (1988). Ils stimulaient de nouvelles recommandations concernant la nutrition des vaches laitières principalement, tenant compte de l'importance significative d'un apport adéquat des acides aminés absorbés. Par conséquent, on concevait des nouveaux concepts d'évaluation des protéines alimentaires basés sur des notions détaillées de l'écologie du rumen.

Concernant l'évaluation des aliments et des principes d'alimentation des herbivores non-ruminants ainsi que des omnivores, il a été développé séparément du fait d'un système digestif totalement différent, Ces données sont compilées par Henry, Vogt & Zoiopoulos (1988);

39

Tisserand (1988). En effet, il sagissait de tenir compte tant de l'apport d'énergie alimentaire que des protéines. En outre, le niveau élevé des performances des porcs et de la volaille exigeait de nouvelles conceptions surtout à l'égard des acides aminés métabolisables.

Pendant les dernières decades, on a tenu considérablement compte de l'ingestion à volonté des ruminants, des porcs et de la volaille comme facteur important de production (Forbes, 1985). En ce qui concerne l'affouragement des ruminants, les scientifiques de France (Jarrige, 1978) reprenaient l'idée de Crampton & Harris (1969) consistant à combiner l'ingestion et la valeur énergétique du fourrage en une 'unité d'encombrement' ressemblant à l'ancienne 'indi­ce de valeur nutritive'. Les connaissances approfondies de l'écologie ruminaire ont mené à de nouvelles idées en ce qui concerne la stratégie d'affouragement. Par exemple d'affourager des rations mixtes pour activer le métabolisme ruminau, ce qui améliore le taux d'ingestion. Con­cernant le pic de production de la vache, des truies et des pondeuses, il est connu qu'un bilan énergétique négatif est provoqué à cause d'une phase dans le retard de l'ingestion, ce qui est compensé ultérieurement par ['adaption de l'affouragement.

Introduction

Livestock converts feed, mainly of vegetable origin, into human food of high quality: milk, meat and eggs. The conversion process is rather complicated. Feedstuffs vary tremendously in composition, they are hydrolysed and partially degraded in the animal's intestines. The re­sulting molecules are absorbed into the blood stream and are ultimately resynthesized in the body organs into macromolecules, such as protein, fat, arid lactose.

Ingestion of feed, its digestion and its conversion to food requires energy, which is provided by the feedstuff. The proportion of the feed energy and of the feed protein (amino acids), which remains available in the animal for food production in the body organs varies considerably, because of various sources of energy losses. The output of food therefore depends largely on the content of essential components of macromolecules, such as amino acids, and of total ener­gy in the feed and on the efficiency of feed conversion, but not exclusively. Livestock has a genetic potential, which determines also in part its capacity to produce food. Thus the pro­duction of food by livestock results from a combined effect of genetic capacity, feed quality and efficiency of feed conversion.

Feeding and nutrition research in livestock has concentrated of course on feed composition (quality) and feed conversion. Breeding and genetic research has tackled the other component of livestock production. However, although in the animals entirely integrated, research work on both features was almost entirely separated and it often still is. Figure 1 illustrates, in a rather simplified manner, the sources and the magnitude of energy losses in a dairy cow. For protein as well as for other kinds of livestock production similar characteristics apply, however, with very different energy losses.

Issues in nutrition and feeding research reflect not only scientific progress but also evolution in society and economy. Scientific progress may have a large impact on sophisticated research in universities, though trends in society and economy affect it also. In research for application on short term in livestock husbandry, the opposite is true.

So in the first decades of this century, research on vitamins wa,s a real topic. Later it became a sideline, because supplementation with synthesized vitamins (scientific progress in chemis­try) to compound feed effectively prevented the detrimental effects of vitamin deficiencies in feedstuffs. Research workers focused their activities instead on feed composition and on feed conversion and did so for several decades. Technological progress (large energy-metabolism units), economic pressures (feed and food shortage in large parts of the world, caused by World War II and by political strategies in various countries) and a substantial increase in consumer's demand for food of animal origin at competitive prices were responsible for it. This boom in research on feed quality and feed conversion reached its peak in the period 1950-1970 and

40

Heat losses

5% Meat

Maintenance (heat)

Methane urinary losses

Faecal losses

/ = genetic potential

Figure 1. Indicative energy losses in a dairy cow (29 kg milk).

resulted in revised feed evaluation systems in many countries in the decades after 1970. These results pushed livestock production up to high outputs at relatively low costs. It provided conditions, which permitted livestock husbandry to produce in ever larger units. This trend was supported simultaneously by spectacular research results in related fields, such as housing, mechanization and breeding. In the last two decades, however, new trends in nutrition and feeding research appeared. Again, as formerly, evolution in science and society were respon­sible. In this paper, we will draw attention to progress in feeding and nutrition research, with emphasis on three items: 1. efficiency of food production by livestock 2. research to meet concern from society about certain aspects of livestock feeding 3. interdisciplinary effects on feeding and nutrition.

Efficiency of food production by livestock

Substantial progress has been made in knowledge of the physiology of nutrition. Energy and protein metabolism in farm animal is much better understood now than before. In combination with the impressive gain in knowledge of rumen fermentation and of the physiological proces­ses in high-yielding farm animals this resulted in a steady increase in efficiency of feed con­version.

Substantial support for this development was provided simultaneously by more and more appropriate and reliable assessment of feed composition on a larger and larger scale.

41

ME (MJ)

158 164 165 155 162 162 164 169 171

Digital system's unit

12 13.8 98.9

8,846 14,100

38.7 98.3 169

24.4

Name (abbr.) of system's unit

SFU UFL NEL (MJ) EFr

VEM ME (Meal) NEL (MJ) ME (MJ) NE (Meal)

Table 1. Indicative requirements, expressed in M J ME and expressed in system's digital unit. Lactating cow; 600 kg live weight; daily yield 20 kg FCM. Data based on van der Honing & Alderman (1988).

Country

Denmark France West Germany East Germany Netherlands Sweden Switzerland Britain US

Efficiency of feed conversion in farm animals1

Ruminants

Blaxter (1962) showed some 30 years ago, that Kellner's concept (1908) underestimates the energetic feeding value of roughages for ruminants and for high performance requires feeding systems rich in concentrates. His research work opened the discussion to reconsider the correctness of the old energy evaluation systems. Accordingly van Es (1974) compiled results of energy-balance trials with cows, mostly in Beltsville, Rostock and Wageningen. Van Es proposed to base the value of the feed, in accordance with Kellner, directly on the energy value of the product, resulting from the feed concerned. Van Es's argument to stick on this 'Net Energy Value', contrary to Blaxter's proposition, refers above all to the direct comparability of the production potential of feedstuffs.

This change in feed energy evaluation, which occurred during the last twenty years stimulated new feeding recommendations for ruminants on the base of metabolizable energy (ME) in many countries. Although based on almost the same framework the systems —just ME or net energy (NE) derived from it — are expressed in diverse ways (Table 1).

Recently van der Honing & Alderman (1988) suggested, therefore, that for planning of feed resources, irrespective of possible use for different kind of animals, there is a need for a com­mon unit of the nutritive value. They favour metabolizable energy as a common basis for ener­gy evaluation. This satisfies the ideas of economists, looking for national or international feed-resource balances (Parris & Tisserand, 1988).

New knowledge about the microbial ecology in the rumen promoted new concepts for protein evaluation in the last twenty years. They acknowledged the amount of amino acids absorbed in the small intestine, originating partly from microbial true protein (MTP) and from that part of the dietary protein that passes undegraded across the rumen (UDP).

1 This part of the paper was presented extensively by Professor Bickel during the Symposium "On the eve of the 3rd millenium, the European challenge for animal production" during the EAAP study meetings in Toulouse.

42

New systems are proposed or in use now, all based on the same principle, distinguishing between the amount of nitrogen and energy available for microbial proliferation together with the absorbability of this micro-organism on one hand and the undegraded amino acids on the other (van der Honing & Alderman, 1988).

Pigs and poultry

'Total Digestible Nutrients' (TDN) were preferred for feed evaluation and for feeding pro­grammes in most countries, for pigs as well as for poultry. TDN defines the relative energetic effect of protein, fat and carbohydrates somewhere between digestible metabolizable energy (Crampton, 1969). Many countries have now chosen digestible energy or metabolizable energy to evaluate pig and poultry feed, respectively, and Henry et al. (1988) doubt whether systems based on NE assessment ought to be preferred.

In protein evaluation of feedstuffs for non-ruminants, the availability of absorbed amino acids with reference to the requirement was recognized to be a more reliable measure of the protein value than simple determination of the 'digestible protein'. Thus evaluation and fee ding principles for protein were concentrated in the last 20 years on the determination of crude protein, excluding non-protein nitrogen, and above all of specific amino acids as lysine, methionine and cysteine.

Non-ruminant herbivores and other farm animals

The different anatomy of the digestive tract between ruminants and non-ruminant herbivores affects the feeding principles and the feed evaluation for horses and rabbits.

Digestible energy and net energy both were used in the past for evaluating the energy value of feeds for horses. Scientists in France proposed a particular horse feed unit (HFU), based on the net energy content of barley. Evaluation of the protein value of feedstuffs is mosüy expres­sed in terms of apparently digestible crude protein (DXP). Since protein, which is not absorbed in the small intestine, may be degraded in the hind gut, the real value of absorbed protein is overestimated by DXP. (Tisserand, 1988).

Besides these agricultural animals, interest has grown during the last twenty years for farming of fur-bearing animals and fishes. Research workers in the Scandinavian countries have studied the physiology and principles of feeding programmes (Tauson, 1988). The requi­rement for both protein and fat is high, much higher than for the animals referred before and comparable to the requirement of cats.

Austreng et al. (1988) has summarized the main aspects of problems in fish farming, based on their own research work and on those of Brett et al. ( 1979). The development of fish farming is one of the most impressive sectors in animal genetics and animal nutrition during the last ten years.

Feed intake of farm animals

Animal nutritionists are engaged foremost in the physiology of nutrition in defining the requi­rement of the animal and in evaluating the feed. About 20 years ago, Crampton (1969) pointed out that it is important to pay attention to voluntary feed intake as well.

Feed intake is doubtless controlled by several factors, which, however, are not entirely understood. Bines (1979) and Forbes (1986) reviewed the theories of food intake control, distinguishing several mechanisms, such as gastric distension and glucostatic, lipostatic and thermostatic control. These factors include those associated with the functions of the gut and the brain, i.e. of the digestive tract, the metabolites of absorbed nutrients, the hormones pro­duced by the body and finally the hypothalamus. Feedback mechanisms, including heat

43

production and metabolization of adipose tissue, and sensory factors have an influence on voluntary feed intake too.

Jarrige (1988) proposed to define a 'fill unit' for both beef and lactating cattle. However the combination of physical, physiological and endocrinological control of the intake shows such a great variety that the propositions of Crampton (1969) and Jarrige (1988) are hardly applied in practice.

For pig fattening, restriction of feed intake during the final stage of growth was common practice in the past, in order to produce optimum lean carcase. Because of breeding for better feed conversion ratio (FCR) pigs were indirectly selected for reduced feeding ad libitum, because low fat accretion improves FCR. Thus feeding ad libitum became common practice without the risk of the production of too much fat in the carcase and restricted feeding at the final stage of fattening was no longer essential. In breeding sows, restriction of energy intake during gestation resulted in better reproductive performance, obviously by reduced accretion of body fat. During lactation, however, feed intake ad libitum does not fully cover requirement, if sows are selected for a large litter. In poultry feeding, particularly the feeding of laying hens, the rapid increase in production during the first ten weeks with progress in breeding shows a lag between requirement and intake, similar to high producing cows. Accordingly, reinforced compound feed with high energy and protein content was proposed and sometimes applied at the onset of production. This was necessary particularly for poultry of small size, which were bred in the past with the idea of saving feed for maintenance requirement.

Table 2. Actual and potential production of dry matter (109 kg) in Europe, other than the Soviet Union. After Lee, 1988.

Western Europe1 Other countries

Actual 201 128 Potential 374 254 1 Belgium, Denmark, France , West Germany, Ireland, Luxembourg, Netherlands and

Britain.

Table 3. Estimated proportion of cereals (%) in compound feeds in some countries. Data from FEFAC, Brussels; quoted by Namur et al, 1988.

1983 1984 1985 1986

Belgium Denmark West Germany France Ireland Italy Netherlands Portugal Spain Britain

44

23 38 21 48 46 50 16 63 66 43

21 40 23 46 46 51 15 61 66 41

24 36 25 47 43 52 15 45 66 43

23 33 24 41 39 51 15 33 63 38

Feed composition and feed quality

Traditionally livestock is fed mainly with feedstuffs, unacceptable for human beings. Thus ru­minants consume mainly grass and vegetable crops, fresh or conserved, supplied with concen­trates, whereas non-ruminants consume concentrates, including a fair amount of cereals.

Concentrates represent a heterogeneous group of feeds. They include cereals, pulses and oilseeds (Todorov, 1988) as well as a large range of byproducts from technological processing of such seeds for human consumption. Through the increasing demand for food from livestock origin, output of such food per production unit rose steadily. Consequently the proportion of concentrates, including cereals, in livestock feed rations increased substantially.

Ill balanced food distribution in the world, occasional failure of crops and famine conditions in a number of countries led to concern in society and evoked criticism.

Livestock production in highly developed countries was considered a competitor for food with hungry people elsewhere in the world. Although the validity of this argument for soil fer­tility and for economic reasons is not strong (de Boer & Bickel, 1988), it has led to intensified research on feed quality and energy conversion in forages and byproducts.

Nutritive quality of forages, especially grass at various stages of growth and its conservation products, received a new momentum in research. Questions about how to increase grass pro­duction and how to improve conservation techniques received an impetus. Lee (1988) illu­strates that it is worthwhile to give priority to these questions (Table 2).

The utilization of byproducts in livestock feeding became a popular line of.research too. First, because the available amount of many 'Classical by-products' of vegetable origin such as extracted oilseed meals, bran and beet pulp grew impressively. Second, because innovation of process technology has continually produced new kinds of by-products. Third, because products once considered-wastes were subjected to research to find out their potential value as livestock feed. Boucque & Fiems (1988) presented an exhaustive review on these kinds of feedstuffs.

Straw and stover represent with an annual production of over 560 million tonnes in the EAAP area (Sundstol, 1988) a very predominant by-product. Attempts to make it more di­gestible for livestock at economic costs have been undertaken for decades but so far with limited success. Hopefully attack with specially equipped bacteria may allow a breakthrough in the near future with large impact for livestock feeding in developing countries.

Similarly research was intensified on by-products of animal origin. Also here 'Classicals', such as fishmeal and products from the rendering industry remained of primary interest. Sub­stantial research was dedicated also to wastes, for example rumen contents, and poultry and pig manure. Miller & de Boer (1988) reviewed the group of by-products of animal origin and their potential.

All this research on forages and by-products has led to the conclusion that ruminants and non-ruminants may be adequately fed with a larger proportion of these feedstuffs in the ration than was thought appropriate earlier. This conclusion means that the proportion of cereals in livestock feeds may fluctuate greatly without harmful effects for livestock production accep­ting that it is primarily governed by market conditions. Table 3, based on data of Namur et al. (1988) illustrates differences for several countries in this respect.

Research to meet society concern about certain aspects of livestock feeding

We have stressed the increasing output from livestock production and the sustaining role of progress in knowledge of nutrition and feed technology. Livestock production units kept gro­wing larger in order to keep production costs as low as possible, with ever more animals per farm unit (poultry in cages, maximization of housing density for pigs, cattle in strawless cubicle

45

Table 4. Effect of supplementation of microbial phytase on phosphorus excretion into manure of broilers with respect to dry matter of feed (g/kg) and of pigs as content in dry matter of faeces (g/kg).

Broilers Pigs

Control Diet 2.7 (100) 16.3 (100) Phytase supplementation1 2.0 (74) 10.9 (67) 1 1,000 units/kg feed

1 unit is the activity that liberates 1 (imol phosphate from phytic acid in 1 minute

Table 5. Total excretion (106 kg/year) ofN and P by livestock in 1983,1988 and in the near future as a result of adaptation in feeding technology.

N 1983 1988 future

P 1983 1988 future

Cattle

444 (100) 363 (82) 328 (74)

56.1 (100) 45.9 (82) 43.5 (78)

Pigs

120 (100) 146 (122) 109 (91)

31.9 (100) 29.2 (92) 20.0 (63)

Poultry

53.3 (100) 56.8 (106)

47 (88)

15.6 (100) 13.6 (87) 7.95 (51)

Total

617 (100) 566 (92) 484 (78)

103.6 (100) 88.7 (85) 71.7 (69)

barns) and a growing application of disease preventing or production stimulating additives to feed rations. Namur et al. (1988) recently reviewed concisely the types of these additives.

Both phenomena, high animal density on farms and ample application of additives in feed rations for livestock, began to raise concern in society. Consumers wondered whether 1. keeping animals in such conditions was acceptable and 2. additives supplemented to feed or parenterally injected might enter the food, which they

should buy and eat. Pollution from industries may cause toxic deposits on vegetation, e.g. grass, which is consumed by livestock. This concern was stimulated greatly by people's increased care for their health on one hand and by progress in chemistry and physics, which permitted the introduction of highly sophisticated detection methods on the other hand. Thus the detection of minute amounts, nanograms (10-12 kg) and even picograms (10~15 kg), of a hazardous chemical in 1 kg of a feedstuff became possible. So one could, in effect detect 6 very dangerous individuals in a world population of 6,000 million people. Stressing exclusively the presence of these indi­viduals without indicating their minute quantitative impact, as has been done quite frequently in inexpert publicity, has turned care often into fear.

All this led to experiments to find out whether (potentially toxic) additives/active agents might pass through the animal into the food and if so, which proportion. So Tuinstra et al. (1981), Vreman (1985) and Oiling et al. (1990) have shown for polychlorobiphenyls (PCBs), organochloric pesticides, toxic heavy metals such as cadmium, lead and mercury, radionucli­des, mycotoxines, dioxines and dibenzofurans the carry-over effects in lactating cows and in beef cattle. This type of research has allowed development of well founded and safe tolerances of contaminants in livestock feeding and will continue to do so, thus reassuring the consumer. Large livestock require large amounts of feed. Thus grass production was pushed up with in-

46

creasing amounts of nitrogen fertilizer. High individual performances in livestock require large supplements of concentrates, generally as compound feed. To overcome deficiencies of in­organic elements in the components of the compound feed, it had become commonplace to supplement with mineral mixtures. At very high production levels, faecal output is greater than the average figure (Figure 1).

Again, society has turned against the livestock husbandry. Air became polluted with nasty odours, phosphorus accumulated in surface waters and killed fish and caused excessive growth of algae. Elements such as phosphorus and nitrogen approached upper critical limits in the soil. Other criticisms were damage by NOx to woods and rising concentrations of NOx in drin­king water. They have induced extensive research on availability of nitrogen from grass and on efficiency of the utilization of phosphorus, as well as other minerals from feedstuffs. Simons et al. (1990) demonstrated that the output of P excretion of broilers and of pigs can be reduced markedly without adverse effects on pig production by appropriate feeding technology. A remarkable issue here is the application of P-releasing enzymes in feeds, which contain substantial amounts of phytine-phosphorus (Table 4).

Similar research with other minerals includes carry-over of heavy metals such as Pb and Cd. The data will help to prevent environmental pollution and toxicity risks of foods as well. Coppoolse et al. (1990) shows for conditions in the Netherlands what progress has been made already and what may be expected in the near future (Table 5). Progress of knowledge on by­product utilization links up with these issues, because process technology of feeds and foods may lead to accumulation of risky substances in by-products. /

In the past 20 years, impressive progress has been made in finding ways to meet concern in society about unacceptable effects of livestock husbandry. Though more research will be necessary, a solid basis is available.

Interdisciplinary effects on feeding and nutrition

In preceding sections of this paper, we have mentioned the impressive progress of rumen physiology and protein metabolism. Modern surgical technology (canulation, catheterization, sensoring) was of utmost importance to accomplish that progress.

Marked advances have been made too in analytical equipment. Various techniques with digestibility in vitro have became popular. In the 1980s, near infrared reflectance has been introduced with promising results. They all speed up assessment of digestibility of feedstuffs, allowing more accurate matching of feed allowance and livestock production. The effect of the application of these sophisticated scientific tools was enhanced enormously by the boiste­rous advance in computer technology.

So feeding and nutrition research became more effective because much more data from one trial can now be analysed than formerly. This also speeds up the solving of hot issues, such as the portion of blame for environmental pollution that can be attributed to livestock husbandry. Development of modern systems of feed evaluation, almost agreed now in many countries, in the 1970s and 1980s would have been slow or impossible without computers.

Biochemistry, biotechnology and genetic manipulation have made substantial progress also in recent years. These disciplines are only partially connected with feeding and nutrition. Still they should be mentioned here, because of the increasing linkage with feeding and nutrition. Again with computer support, simulation models of animal physiology have been developed, revealing gaps in nutritional science and in its research priority in relation to breeding and genetics. Thus the integration of feeding and breeding research becomes more and more a reality after many years of largely separated activities.

That process will be re-enforced by progress in genetic manipulation. The combined effect of such an interdisciplinary approach and of continuing progress in knowledge of feeding and nutrition shall promote very high individual production levels (de Boer, 1985). Examples of

47

such animals, still maintaining good health and longevity, are becoming more and more common. A livestock herd of such extremely high productivity means a decrease in size and that means a smaller manure burden with favourable effects on the rate of environmental pollution. However, this will cause substantial tension in society because of the unavoidable decrease in the number of livestock farmers.

However animals will be kept in highly automated farm systems, allowing, for instance, fully automated milking of cows and matching of feed input and production, so reducing feed costs. Individual preference for feeding intervals with feed that is frequently monitored for its actual feeding value will become a real option in such systems. Such systems will meet high standards for animal welfare and for restriction of environmental pollution.

Acknowledgment

The authors thank Y. van der Honing for his valuable assistance in preparing this paper.

References

Austreng, E., Grisdale-Helland, B., Heiland, S J. & Storebakken, T., 1988. Farmed Atlantic Salmon and Rainbow Trout. In: de Boer, F. & Bickel, H. (ed.): Livestock Feed Resources and Feed Evaluation in Europe. Elsevier, Amsterdam, pp. 369-374. ISBN 0-444-^2996-4.

Bines, J.A., 1979. Voluntary Food Intake. In: Broster & Swan (ed.): Feeding Strategy for the High YieldingDairy Cow. Granada Publ., London. EAAPPubl. 25, ISBN 0-258-97126-6.

Blaxter, K.L., 1962. The Energy Metabolism of Ruminants. Hutchinson, London. Boucque, Ch.V. & Fiems, L.O., 1988. Vegetable by-products of agro-industrial origin. In: de

Boer, F. & Bickel, H. (ed.): Livestock feed resources and feed evaluation in Europe. Elsevier, Amsterdam, pp. 97-135. ISBN 0-444-42996-4.

Brett, J.R. & Groves, TD.D., 1979. Physiological Energetics. In: Hoar, Randall & Brett (ed.): Bioenergetics and Growth. Fish Physiology 8:279-352, Academic Press, New York.

Coppoolse, J., van Vuuren, A.M., Huisman, J., Janssen, W.M.MA., Jongbloed, A.W., Lenis, N.P. & Simons, P.C.M., 1990. De uitscheiding van stikstof, fosfor en kalium door land­bouwhuisdieren, Nu en Morgen. DLO, Wageningen. ISBN 90-9003497-8.

Crampton, E.W., 1969. Applied Animal Nutrition. 2nd ed. Freeman & Co., San Francisco. de Boer, F., 1986. Perspectives of bovine production; from cow to supercow? In: Proceedings

of a DSA symposium: Future production and productivity in livestock farming: Science versus politics. Elsevier, Amsterdam, pp. 21-33. ISBN 0-444-42704-X.

de Boer, F.& Bickel, H., 1988. Impact of feed in livestock production. In: de Boer, F. & Bickel, H. (ed.): Livestock feed resources and feed evaluation in Europe. Elsevier, Amsterdam, pp. 3-10. ISBN 0-444-42996-4.

Forbes, J.M., 1986. The Voluntary Food Intake of Farm Animals. Butterworths, London. ISBN 0-408-11154-2.

Henry, Y., Vogt, H. & Zoiopoulos, P.E., 1988. Pigs and Poultry. In: de Boer, F. & Bickel, H. (ed.): Livestock Feed Resources and Feed Evaluation in Europe. Elsevier, Amsterdam, pp. 299-354. ISBN 0-444-42996-4.

Jarrige, R., 1988. Ingestion et digestion des aliments. In: Jarrige, R. (ed.): Alimentation des Bovins, Ovins et Caprins. INRAPubl., Paris. ISBN-7380-0021-5.

Kellner, O., 1908. Grundzuge der Futterungslehre. 1. Aufl., Parey, Berlin. Lee, J., 1988. Forages. In: de Boer, F. & Bickel, H. (ed.): Livestock feed resources and feed

evaluation in Europe. Elsevier, Amsterdam, pp. 13-46. ISBN 0-444-42996-4.

48

Miller, EL. & de Boer, F., 1988. By-products of animal origin. In: de Boer, F. & Bickel, H. (ed.): Livestock feed resources and feed evaluation in Europe. Elsevier, Amsterdam, pp. 159-196. ISBN 0-444-42996-4.

Namur, A.P., Morel, J. & Bickel, H., 1988. Compound animal feed and feed additives. In: de Boer, F. & Bickel, H. (ed.): Livestock feed resources and feed evaluation in Europe. Else­vier, Amsterdam, pp. 197-209. ISBN 0-444-42996-4.

Oiling, M., Derks, HJ.G.M., Berende, PL.M., Liem, A.KD. & de Jong, A.P.J.M., 1990. Toxicokinetics of eight 13C-labelled polychlorinated Dibenzo-P-Dioxines and -Furans in lactating cows. Poster. 10th International meeting "Dioxin 90" in conjunction with EPRI PCB-seminar. Bayreuth.

Parris, K.F. & Tisserand, JL., 1988. A Methodology to Complete a National Feed Utilisation Matrix using European Data. In: de Boer, F. & Bickel, H. (ed.): Livestock Feed Resources and Feed Evaluation in Europe. Elsevier, Amsterdam, pp. 375-388. ISBN 0-444-42996-4.

Simons, P.C.M., Versteegh, H.A.J., Jongbloed, A.W., Kemme, PA., Slump, P., Bos, KD., Wolters, M.G.E., Beudeker, R.F. & Verschoor, G.J., 1990. Improvement of phosphorus availability by microbial phytase in broilers and pigs. Br. Journal of Nutrition, in press.

Sundst0l, F., 1988. Straw and other fibrous by-products. In: de Boer, F. & Bickel, H. (ed.): Livestock feed resources and feed evaluation in Europe. Elsevier, Amsterdam, pp. 137-158. ISBN 0-444-42996-4.

Tauson, AM., 1988. Fur-Bearing Animals. In: de Boer, F. & Bickel, H. (ed.): Livestock Feed Resources and Feed Evaluation in Europe. Elsevier, Amsterdam, pp. 355-368. ISBN 0-444-42996-4.

Tisserand, J.L., 1988. Non-ruminant herbivores: horses and rabbits. In: de Boer, F. & Bickel, H. (ed.): Livestock Feed Resources and Feed Evaluation in Europe. Elsevier, Amsterdam, pp. 279-298. ISBN 0-444-42996-4.

Todorov, NA., 1988. Cereals, pulses and oilseeds. In: de Boer, F. & Bickel, H. (ed.): Livestock Feed Resources and Feed Evaluation in Europe. Elsevier, Amsterdam, pp. 47-96. ISBN 0-444-42996-4.

Tuinstra, L.GM.Th., Vreman, K., Roos, A.H. & Keukens, HJ., 1981. Excretion of certain chlo-robiphenyls into the milk fat after oral administration. Neth. Milk and Dairy Journal 35: 147-157.

van der Honing, Y. & Alderman, G., 1988. Ruminants. In: de Boer, F. & Bickel, H. (ed.): Live­stock Feed Resources and Feed Evaluation in Europe. Elsevier, Amsterdam, pp. 217-267; p. 401. ISBN 0-444-42996-4.

van Es, A J.H., 1974. Feed Evaluation for Dairy Cows. E.A.A.P. 25th Ann. Meeting, Copen­hagen. Mimeo.

Vreman, K., 1985. Organochloric compounds and heavy metals. Neth. Milk and Dairy Journal 39:58-59.

49

Views on various strategies for development in dairy cattle production

A. Neimann-S0rensen

National Institute of Animal Science, Foulum, Postboks 39,8830 Tjele, Denmark

Summary

Several investigations indicate that tightened attention on the consequences of one-sidedly focussing on high milk yields is needed due to the accompanying consequences for the health and utility of the cow. Strategically for the long run the main goal for the production, therefore, is best expressed as maximum net income per kg of unit of milk, butterfat or milk protein, and not as maximum milk yield or gross margin. The implications of such a strategic and broad goal has been studied in an interdisciplinary analysis and synthesis, comparing the effects of one-sided selection on yield (Y) and index selection including 13 traits (I). The results clearly indicate that strategy I is very superior to strategy Y, and that this superiority increases with time. After 20 years of selection the genetic capacity for milk yield is about 1,000 kg higher in line Y than in line I, but line I is economically superior by about 2,000 DKr (~ 300 $) per 10,000 kg of milk. Key words: Dairy cattle production, gross margin, net income, index selection.

Résumé

Plusieurs enquêtes ont démontré qu'il convient d'accorder une attention particulière aux conséquences d'une étude trop partielle des hauts rendements laitiers en raison des incidences qu'ils peuvent avoir sur la santé et la rentabilité de la vache. En matière de stratégie à long terme, le but principal de la production s'exprime le mieux en termes de revenu net par kg d'unité de lait ou de protéine lactée et non pas en fonction de rendement laitier maximal ou de marge brute. Les conséquences d'un but stratégique aussi vaste ont été étudiées selon une analyse et une synthèse interdisciplinaires, comparant un échantillon partiel en fonction du rendement (Y) et un échantillon témoin comprenant 13 critères (I). Les résultats indiquent que la stratégie I est nettement supérieure à la stratégie Y, et que cette supériorité augmente avec le temps. Vingt ans de sélection ont démontré que la capacité génétique pour le rendement laitier est supérieure d'environ 1,000 kg selon l'approche Y par rapport à l'approche I, mais la rentabilité de l'approche I est plus élevée d'environ 2,000 DKr (~ $ 300) par 10,000 kg de lait. Mots-clés: Production de vaches laitières, marge brute, revenu net, échantillon témoin

Introduction

Dairy production over the last two decades has undergone a rapid growth. New technologies have been developed for grazing and forage harvesting, for feeding and milking. Through physiological and nutritional research, feeding principles and formulation of optimum rations have been greatly improved, and extensive use of scientific principles and new technologies has lead to the introduction of very efficient breeding schemes in most European countries. These technologies have been accompanied by economics of scale, demonstrated by the fact that overall cow numbers remained constant up through the 60'ties and 70'ties, and lately have

51

r

u a

£

milk price

net income per kg milk

a

I? a

S u

Kg butterfat per cow

Figure 1. Total costs per kg milk and gross margin at increasing yield per cow and year in Holstein-Friesian herds with different management (Allaire & Thraen, 1985).

1965 n—i—i—i—r

1970 1975' 1980 Year

T 1—1—1—r-

1985 1990

Figure 2. Increase in genetic ability for butterfat yield in the breeds Red Danish (RDM) and Danish Black and White (SDM). Percentage per year.

diminished markedly, e.g. by app. 20% in the EEC countries since the introduction of the milk quotas in 1983. The herd size has increased, in several countries more than doubled.

The dairy industry has made its contribution to these technological changes and increased efficiency. Figures from FRG over the years 1956-76 illustrates this (Jahnke, 1983): labour input (man-hours cow-1 year-1) was reduced to half or less, milk yield (kg cow-1 year-1) in­creased with 40%, meat yield (kg cow-1 year-1) was unchanged and labour productivity (kg milk man-hour-1) 5-doubled. The developments reflect the dairy farmers attempts to maintain their living standard relative to the rest of the society. The latter has profited more than the former. Thus, for example the purchasing power for milk has increased about 3 times both for milk and slaughter cattle (Jahnke, 1983).

Taking an overall view of what has been going on in the various places, it may be said that the dairy farmers rapidly and cleverly have utilized the newest research results with the main effort to increase milk yield per cow, apparently out from the believe that this will give them the greatest economic profit. This is not necessarily so. In the long term strategic planning of the dairy enterprise it is necessary also to consider the amount and quality of the accompanying beef production from the herds, and the genetic and physiological consequences of focussing one-sidedly on high milk yield. Several investigations indicate that tightened attention is needed on the accompanying consequences for the health and utility of the cow. Many of these are negative, and the marginal profit of the efforts thereby reduced. Strategically, for the long run, the main goal for the production (breeding, feeding and management) therefore is best expressed as maximum net income per kg of milk or butterfat + milk protein (0stergaard et al., 1989), cf. Figure 1. Furthermore, a broad goal like this is in harmony with the increasing attention in the public to the well-being of the animals and to the quality of the product.

In order to investigate the implications of such a strategic and broad goal in the dairy pro­duction an interdisciplinary analyses and synthesis was made based on published and unpu-

52

blished results over the later years (0stergaard & Neimann-S0rensen, 1989). The main results of the study are presented here as being illustrative of developments of the past and possible consequences for the future. Presumably they are representative for a great section of the dairy industry in our part of the world.

Progress in yield

Over the years the genetic progress in yield has been estimated for several breeds in Western Europe and USA. Christensen (1980) has given a survey of the results and finds that the genetic gain in milk yield or butterfat has been close to 1% in the period 1950-1975. Newer investi­gations indicate that these results represents some overestimation, and Van Vleek et al. (1986) finds a yearly genetic gain of 40 kg milk — i.e. 0.5% in HF in USA during recent years. Estimates of yearly genetic gains in butterfat production for Danish breeds during 1965-1988 are depicted in Figure 2. There are two trends identifiable, probably shared with several other populations in Europe during this period: 1. as new and more efficient breeding programs are brought into use the genetic progress in

yield goes up from 0.8 to 1.2-1.3% annually. With present breeding structure and practices this is a likely maximum which can be reached in practice.

2. massive importation of HF-genes in mid-80'ties has boasted genetic progress, but levels off as the local breeding programs become more efficient and the difference in genetic level between the populations diminishes.

Figure 3 shows the increase in total yield, as it has taken place over the years 1970-1988 in the Danish Red and the Danish Black and White dairy cows, and separated in gain due to breeding and to environment (feeding, management). The large fluctuations of the latter is an

53

^

1

a

ß

milk price

net income per kg milk

V

a. .3 ?

E

Kg butterfat per cow

Figure 1. Total costs per kg milk and gross margin at increasing yield per cow and year in Holstein-Friesian herds with different management (Allaire & Thraen, 1985).

diminished markedly, e.g. by app. 20% in the EEC countries since the introduction of the milk quotas in 1983. The herd size has increased, in several countries more than doubled.

The dairy industry has made its contribution to these technological changes and increased efficiency. Figures from FRG over the years 1956-76 illustrates this (Jahnke, 1983): labour input (man-hours cow-1 year-1) was reduced to half or less, milk yield (kg cow-1 year-1) in­creased with 40%, meat yield (kg cow-1 year-1) was unchanged and labour productivity (kg milk man-hour-1) 5-doubled. The developments reflect the dairy farmers attempts to maintain their living standard relative to the rest of the society. The latter has profited more than the former. Thus, for example the purchasing power for milk has increased about 3 times both for milk and slaughter cattle (Jahnke, 1983).

Taking an overall view of what has been going on in the various places, it may be said that the dairy farmers rapidly and cleverly have utilized the newest research results with the main effort to increase milk yield per cow, apparently out from the believe that this will give them the greatest economic profit. This is not necessarily so. In the long term strategic planning of the dairy enterprise it is necessary also to consider the amount and quality of the accompanying beef production from the herds, and the genetic and physiological consequences of focussing one-sidedly on high milk yield. Several investigations indicate that tightened attention is needed on the accompanying consequences for the health and utility of the cow. Many of these are negative, and the marginal profit of the efforts thereby reduced. Strategically, for the long run, the main goal for the production (breeding, feeding and management) therefore is best expressed as maximum net income per kg of milk or butterfat + milk protein (0stergaard et al, 1989), cf. Figure 1. Furthermore, a broad goal like this is in harmony with the increasing attention in the public to the well-being of the animals and to the quality of the product.

In order to investigate the implications of such a strategic and broad goal in the dairy pro­duction an interdisciplinary analyses and synthesis was made based on published and unpu-

52

~T 1 7——) 1 T — T 1 7 " I I 1 - ~ 1 1 1 I 1 i i "'• I I I 1

1965 1970 1975 1980 1985 1990 Year

Figure 2. Increase in genetic ability for butterfat yield in the breeds Red Danish (RDM) and Danish Black and White (SDM). Percentage per year.

blished results over the later years (0stergaard & Neimann-S0rensen, 1989). The main results of the study are presented here as being illustrative of developments of the past and possible consequences for the future. Presumably they are representative for a great section of the dairy industry in our part of the world.

Progress in yield

Over the years the genetic progress in yield has been estimated for several breeds in Western Europe and USA. Christensen (1980) has given a survey of the results and finds that the genetic gain in milk yield or butterfat has been close to 1% in the period 1950-1975. Newer investi­gations indicate that these results represents some overestimation, and Van Vleek et al. (1986) finds a yearly genetic gain of 40 kg milk — i.e. 0.5% in HF in USA during recent years. Estimates of yearly genetic gains in butterfat production for Danish breeds during 1965-1988 are depicted in Figure 2. There are two trends identifiable, probably shared with several other populations in Europe during this period: 1. as new and more efficient breeding programs are brought into use the genetic progress in

yield goes up from 0.8 to 1.2-1.3% annually. With present breeding structure and practices this is a likely maximum which can be reached in practice.

2. massive importation of HF-genes in mid-80'ties has boasted genetic progress, but levels off as the local breeding programs become more efficient and the difference in genetic level between the populations diminishes.

Figure 3 shows the increase in total yield, as it has taken place over the years 1970-1988 in the Danish Red and the Danish Black and White dairy cows, and separated in gain due to breeding and to environment (feeding, management). The large fluctuations of the latter is an

53

300

280

260

5 240

3 E 220

200-

DANISH RED

Environment

180-^—i—i—i—i—i—I—i—i—i—i—i—1—1—i—i—i—i—i-1—i—i—i—'—r 1964 1968 1972 1976 1980 1984 1988

Year

300

280-

260-

DANISH BLACK & WHITE

5 240-

3

220-

200

Environment

Genetic

180 * i i i i i i i » .i i i i i i i i i i T i i i i i i 1964 1968 1972 1976 1980 1984 1988

Year

Figure 3 Trend in yield (Danish Red and Danish Black and White cattle) composed by accumulated genetic increase and environmental improvement. Kg butterfatper cow andyear.

54

Tabel 1. Feeding level and feed efficiency (Friis Kristensen & Aaes, 1989).

Feeding level Feed % Reduction per Marginal Scan, feed units efficiency multiplum of efficiency

Feed efficiency

99.4 96.0 92.1 87.9 83.5

% Reduction per multiplum of maintainance

-0.3 -1.7 -2.9 -3.8 -4.5

12 99.4 -0.3 81 14 96.0 -1.7 70 16 92.1 -2.9 60 18 87.9 -3.8 49 20 83.5 -4.5 39

illustration of the farmers' adaptation to changing conditions such as availability of forages due to climate, price ratio milk: feed, etc. Stabilized and high milk prices, since the introduction of quotas in the EEC clearly have prompted the farmers to exploit the production capacity of the cows in recent years.

Overall, the considerable increase in total butterfat yield over the 18 years of 80-90 kg (38-40%) is rather evenly caused by breeding and environment (feeding and management).

The effect of feeding level on feed efficiency

It is wellknown that the response of dairy cows, measured as the sum of energy expenditures on maintenance, milk yield and energy retention with increasing feeding level, is following the law of diminishing returns. Numerous results from feeding experiments and measures of calorimetric balances have shown a reduction in digestibility, especially of cell wall substances as feeding level goes up cf. ARC (1965), NRC (1978), van Es (1978). To quantify this effect Friis Kristensen & Aaes (1989) have analysed recent Danish feeding experiments. The results agree well with the literature, and they are presented in Table 1. Feed efficiency is defined as net energy in milk, gain and maintenance over net energy intake.

It is seen that when feeding level increases from 12 Scand. f.u. (-100 MJ NE ~ milk yield 18 kg) to 20 Scand. f.u. (-150 M J NE - milk yield 50 kg) the reduction in feed efficiency per multiple of maintenance increased from less than 2 percentage units to above 4 percentage units. Above 100 MJ NE per cow per day the average efficiency decreases at an increasing rate from 100% down to 84%, and the marginal efficiency is reduced from 81% to 39%.

Feed intake capacity

The feed efficiency as just described together with the feed intake capacity determines the amounts of nutrients from the feed which can be made available for the lactopoiesis in the udder. If these come short, the requirement for energy mobilization is increased in the first weeks after calving, and consequently the risk of metabolic diseases, fertility problems etc. It is therefore important to consider how feed intake capacity of the cows has developed during the past years with the remarkable increase in yield due to intensive selection.

Korver et al. (1987) found a heritability of 0.55 for feed intake in heifers, corrected to constant metabolic weight it was 0.17. Andersen (1989) refers to Danish investigations with performance tested bulls, where h2 for intake was found to be 0.3-0.5 with a phenotypic coefficient of variation of 5-8%.

Genetic correlations between feed intake and milk yield have been reported by several authors, cf. Korver (1988), Svendsen & Husab0 (1987). Under ad libitum feeding they have been found to vary from 0.1-0.7, being lowest in the first weeks p.p.

55

Table 2. Estimates of parametres for number of diagnoses of mastitis and digestion diseases per lactation/year.

Mastitis h2

Digestion diseases h2

Mean

0.025 0.300 0.900

0.020 0.250 0.400

Range

0.01-0.04 0.20-0.40 0.80-1.00

0.01 - 0.03 0.20-0.30 0.30-0.50

100-

90-

80-

K 7 ° " J 60-

e a 50-

3 40-

^ 30-

20-

10-

0-

^ ^ profit 1

1 i i

profit 2 s '

^*^^ mastitis

— —T 1 1 r

• " — ^ _ ^ - - " « -b

-4

-3 •2'

-1

- 1

- 2

- 3

- 4

- 5

- 6

- 7

- 8

- 9

I

.2

c

50 100 150 200 250 300 350 Genetic gain milk, kg

400 450 500

Figure 4. Genetic changes in milkyieldper cow and number of cases of mastitis per 100 cows using index selection with varying relative weights on the two traits in the aggregate genotype. Profit 1 - relative economic weight milk: mastitis = 1:3,000. Profit 2 ~ relative economic weight milk: mastitis - 1:1,000.

Oldenbroek (1984) and Holmes (1988) found in accordance with the above results that the correlated response in feed intake following selection for higher yield lacks behind. If we assume a genetic correlation of 0.4-0.6 and h2 for intake to be 0.3, then it can be calculated that a 15% rise in yield (1,000 kg milk) will lead only to 5-7% higher feed intake capacity.

56

Milk yield and beef production capacity

Without going into details several investigations on different dairy breeds indicate the existence of a positive, but weak association between milk yield and growth capacity, but a negative association between milk yield and muscularity (cf. Andersen, 1989). In many breeds the latter has been more pronounced through the later years influx of genetic material from North American Friesians. The associations are physiologically comprehensible, as more factors, such as hormone systems, high feed utilization or low maintenance requirements will favour both milk yield and growth.

Health and milk yield

The health status of the herd is of great concern to the dairy farmer. With diseases follows veterinary costs, loss of production, involuntary culling, higher costs for recruitment etc. The economic outcome may be seriously reduced, and present views on animal welfare is incon­sistent with high disease pressure in the herds.

Unfortunately, disease registrations in dairy cows under commercial herd conditions are difficult to carry out, informations are scarce, and reliable statistics on the disease frequencies and their development over the later years are few for most populations.

The most comprehensive investigations on disease frequencies in dairy herds have been carried out in the Scandinavian Countries, and they were recently surveyed by Christensen (1989), Emanuelson (1988) and Solbu (1984). Mastitis is by far the most frequent and losing disease, accounting for 30-40% of all diseases, and with incidencies going up to 0.63. Com­pared to this, metabolic diseases (ketosis and milk fever) occur less frequent. According to Scandinavian disease recording statistics the incidencies vary from 0.05-0.20. Among repro­ductive diseases, retained placenta is the one which is easiest and best recorded. It seems to occur with a frequency of 5-10 per 100 cows (Anon, 1988; Christensen, 1989). Diseases in legs and claws apparently represent only a small part of registrated diseases in dairy cows. Affections of the claws make up 5-10% of all diagnosed diseases.

There are only few informations on the time trends in disease frequencies in the dairy popu­lations, although it is a common supposition that they have been increasing. Since the occurrence of diseases is greatly influenced by environmental factors such as housing, feeding and management time trends are not reliable in disclosing changes in the animals true disease resistance. Such information, however, can indirectly be gained from selection experiments for high vs low yield, and from studies of the correlated responses to selection for higher milk yields.

Two recent American selection experiments, (Wilk, 1988; Bertrand et al., 1985) show con-cordandy that selection for high yield enhances the disease pressure and as a consequence the veterinary costs.

Correlated responses in disease frequencies with selection for higher yields have been stu­died on basis of extensive herd recordings in Scandinavia (Steine, 1988; Emanuelsen et al., 1988; Eriksson, 1988; Syväjärvi et al., 1986). The results are highly concordant, they are sum­marized in Table 2, and their reliability are confirmed by Steine (1988) and Eriksson (1988) comparing breeding on values of sires and sons or breeding values estimated on independent daughtergroups. Both for frequencies of mastitis and metabolic diseases the genetic correla­tions to milk yield are unfavorable. The issue is further illustrated in Figure 4, based on model calculations by Christensen (1989a), and showing the changes in number of cases of mastitis associated with genetic progress in milk yield, and how this can be modified using index selection for total economic merit with varying relative economic weights on the two traits in an aggregate genotype.

57

Reproduction and milk yield

Reproductive capacity of the dairy cow is of great economic importance. Low reproduction in the herds means higher age at first calving, lower yield and less calves per cow/year, higher culling rates and less opportunities for voluntary selection within the herd, higher veterinary costs, etc. It is generally found that impaired reproduction is the most common reason for culling. AI statistics show only small changes, if any, over the years. Gustafsson (1988) found practically unchanged non-return rates and calving interval for all milk recorded cows in Sweden over the years 1950-1986, while the average yield was nearly doubled. From 1968-1986 the non-return rate for milk recorded cows in Denmark went down by 3%-units and the calving interval increased by app. 10 days (Christensen, 1989b). Such statistics are greatly influenced by the technical level of the AI-work, the farmers practices and skill in heat detec­tion and the feeding of the cows around inseminations, and they are not suitable for detection of any genetic association between yield and reproductive capacity of the cows. The same can also be inferred indirectly from the frequent observations that high yielding herds with high level of management exhibit better reproduction results than lower yielding herds, whereas within herds the highest yielding cows have the lowest reproductive performance.

It is thus necessary to resort to genetical studies to see what changes have taken place in the reproductive capacity of the dairy cows over the years.

Late pregnancy and a consequently long calving interval favours the 305 days yield due to the influence of the foetus, and the yield in the following lactation will also be higher. These and other phenotypic interactions between yield and reproduction complicate the assessment of the genetic correlations between yield and reproductive capacity, and on this background it is comprehensible that the abundant literature on the topic is controversial. Surveys by Hollis & Smith (1987) and Christensen (1989b) both conclude that there exists a weak but unfavo­rable genetic correlation between yield and reproduction. In a very recent study on Dutch data van Arendonk et al. (1989) found genetic correlations between first lactations 305 days yield and service period and days open to be 0.22 and 0.64, respectively. Christensen (1989b) con-cordandy found on Danish data a negativ correlation of 0.40 between the sire index for daughter fertility and the sire index for milk production traits. Furthermore, regression analysis showed a curvelinear relationship, indicating that the unfavorable effect of yield on reproduc­tion increases as yield capacity goes up.

Synthesis

For the long term competitiveness of a dairy breed — or the dairy industry as a whole — the choice of the most appropriate goal is important. This has often been neglected in the past, where selection on single traits particularly milk yield has been commonplace. Thereby the differential importance of the improvement of the individual traits and the associated changes in other traits for the overall economy of the enterprise is overseen. The gross margin per cow as most often used may be an appropriate goal in the short term, because labour and other fixed costs in this situation will be unchanged. It is, however, unsuitable in cases where the production is limited by quotas as well as for the long term planning of the breeding. In this situation the strategy must aim at minimizing the total costs per kg of milk as already mentioned. Such a breeding goal will give maximum benefit to the dairy farmers, and it will secure the dairy enterprise, inclusive the income from sale of meat, its long-term competiti­veness in a future open market. Minimizing the total costs per kg of milk is resulting in maximizing the net income per kg of milk for given milk price.

With this goal as starting point, and based on the above described genetic parameters and associations, analyses have been performed to elucidate the consequences of two breeding strategies: one-sided selection on yield (Y) and index selection (I).

58

Tabel 3. Annual genetic progress from one sided selection on milk (Y) and from index selection (I).

Year

1 3 5 10 15 20

Y

86 80 75 62 49 35

Net income

total.

I

146 144 142 139 135 132

per cow (Dkr)

Y

114 109 104 90 77 64

from milk

I

69 67 63 56 50 44

Mi

Y

114 114 114 114 114 114

Ik per cow

(kg)

I

69 68 67 64 61 57

Dkr. per 10000 kg milk 180

Kg per cow 10000

9500-

9000

8500

8000

2 "v

1—^7500

Figure 5. Yield per cow and annual genetic progress in net income per 10,000 kg of milk when selecting solely on milk (Y) and on a selection index (I).

In both strategies it was assumed that a traditional breeding scheme with progeny testing of sires was applied in an active population of 300,000 dairy cows. The marginal net income per kg genetic progress in milk was assumed to be equal to 1.00 Dkr. in the base population de­creasing with 0.02 Dkr. per 100 kg genetic improvement of milk. In the index-strategy (I) the selection was based on a selection index including 13 traits (growth rate, muscularity, female fertility, calving performance, quality of legs, strength of udder, placement of teats, milk ability, temperament, resistance to mastitis and resistance to other diseases).

59

In both strategies it was assumed that 30% of the cows were served by young sires. In all simulation runs the steady state genetic progress measured in Dkr. per kg of milk were optimized. The main results are presented in Table 3.

It appears that strategy I is very superior to strategy Y and that this superiority increases with time. In strategy Y the net income from milk is higher than the total net income because of the unfavorable genetic correlations between milk yield on the one hand and reproduction and diseases on the other. In year 20 the annual genetic progress in milk yield is twice as large in strategy Y as in strategy I, but the genetic progress in net income is nearly 4 times as large in the latter. If the annual genetic progress is expressed in Dkr. per 10,000 kg of milk the superiority of strategy I becomes even higher. This is illustrated in Figure 5 from which it appears that one sided selection for milk may result in very low and — after 18 years — even negative genetic progress in net income per kg of milk in spite of the fact that the genetic progress in milk yield still is very high. It should be noticed that after 20 years of selection the genetic capacity for milk yield is about 1,000 kg higher in line Y than in line I, but line I is economical superior namely about 1500 Dkr. per cow and about 2,000 Dkr. per 10,000 kg of milk.

References

Allaire, FJt. & Thraen, C.S., 1985. Prospectives for genetic improvement in the economic efficiency of dairy cattle. J. Dair. Sei. 68.

ARC, 1965. The nutrient equirements of farm livestock. No. 2 ruminants. London, pp 264. Andersen, BB., 1989. Genetiske og avlsmasssige aspekter vedr0rende foderoptagelse, fode-

rudnyttelse og k0dproduktionsegenskaber. p. 45-63. In: 0stergaard, V. & Neimann-S0ren-sen, A. (ed.). Grundlag for valg af avlsmâl og tilh0rende Produktionssystem i maelkepro-duktionen. Rep. no. 660. Nat. Inst. Animal Sei., Denmark, pp 157.

Anon., 1988. Djurhälsoprogram 87. Meddelande no. 150. Svensk Husdjurskötsel etc. Hâllsta. pP19.

Bertrand, J.A., Berger, PJ., Freeman, A.E. & Kelley, D., 1985. Profitability in daughters of high versus average Holstein sires selected for milk of daughters. J. Dairy Sei. 68:2287-2294.

Christensen, L.G., 1980. Direkte opdatering som metode til avlsvaerdivurdering i kvaegavlen. Rep. no. 489. Nat. Inst. Animal Sei., Copenhagen, pp 270.

Christensen, L.G., 1989a. Sundhed og avl. p. 64-83. In: 0stergaard, V. & Neimann-S0rensen, A. (ed.): Grundlag for valg af avlsmâl og tilh0rende Produktionssystem i mselkeproduktio-nen. Rep. no. 660. Nat. Inst. Animal Sei. Denmark, pp 157.

Christensen, L.G., 1989b. Reproduktion og avl. p. 84-100. In: 0stergaard, V. & Neimann-S0-rensen, A. (ed.): Grundlag for valg af avlsmâl og tilh0rende Produktionssystem i maelke-produktionen. Rep. no. 660. Nat. Inst. Animal Sei. Denmark, pp 157.

Emanuelson,V., 1988. Recording of production diseases in cattle and possibilities for genetic improvement: A review. Livest. Prod. Sei. 20:89-106.

Eriksson, J.-A., 1988. Nationale rapporter. Proc. Nordic Seminar on breed evaluation for diseases. Sept. 1988. Denmark, p. 69-74.

Friis Kristensen, V. & Aaes, O., 1989. Fodemiveauets betydning for fodereffektiviteten. In: 0stergaard, V. & Neimann-S0rensen, A.: Basis for choice of breeding goal and matching production system within herds. Rep. no.660. Nat. Inst. Animal Sei. Denmark, pp 155.

Gustafsson, H„ 1988. God frugtbarhed og h0j production kan fórenas. Husdjur 3:32-33. Hollis, N.E. & Smith, R.D., 1987. The effects of peripartum events on breeding performance

of dairy cows. Vet. Clin. N.Amer. 3:501-511. Jahnke, H.E., 1983. Livestock in economic development. In: Neimann-S0rensen, A. & Tribe,

D.E.: World Animal Science, vol. Al:307-329.

60

Korver, S., 1988. Genetic aspects of feed intake and feed efficiency in dairy cattle. A review. Livestock Prod. Sei. 20:1-13.

Korver, S., Vos, H. & van der Werf, J.H.H., 1987. Performance test results of young bulls in relation to feed intake and efficiency of female progeny, p. 93-98. In: Korver, S., Averdunk, G. & Bech Andersen, B. (ed.): Performance testing of A.I. bulls for efficiency and beef production in dairy and dual purpose breeds. EAAP-publ. no. 34. Pudoc. Wageningen. 214 pp.

NRC. 1978. Nutrient requirements of dairy cattle. 5. rev. ed. 0stergaard, V. & Neimann-S0rensen, A., 1989. Basis for choice of breeding goal and matching

production system within dairy herds. Rep. no. 660. Nat. Inst. Animal Sei., Denmark, pp 155.

0stergaard,V, Korver, S., Solbu, H., Andersen, B£., Oldham, J. & Wiktorsson, H., 1990. Efficiency in the dairy cow. Livest. Prod. Sei. In press.

Philipsson, J., 1981. Genetic aspects of female fertility in dairy cattle. Livest. Prod. Sei. 8: 307-319.

Solbu, H., 1984. Disease recording in Norwegian dairy cattle. 2. Heritability estimates and progeny testing for mastitis, ketosis and "all diseases". Ztsch.Tierz.und Tiichtbiol. 101:51— 58.

Steine, T., 1988. Nationale rapporter. Proc. Nordic Seminar on breed evaluation for diseases. Sept. 1988. Denmark, pp 75-79.

Svendsen, M. & Husab0, J.O., 1987. Feed conversion and feed intake in Norwegian Red Cattle. 38. Ann. Meeting EAAP. Lissabon, pp 12. '

Syväjärvi, J., Saloniemi, H. & Grohn,Y., 1986. An epidemiological and genetic study on re­gistered diseases in Finnish Ayrshire cattle. 4. Clinical mastitis. Acta Vet. Scand. 27:223-234.

van Arendonk, JAM., Hovenier, R. & de Boer, W., 1989. Phenotypic and genetic association between fertility and production in dairy cows. Livest. Prod. Sei. 21:1-12.

van Es, A.H., 1978. Feed evaluation for ruminants. Livest. Prod. Sei. 5:331-345. van Vleck, LJD., Westell, RA.& Schneider, J.C., 1986. Genetic change in milk yield estimated

from simultaneous genetic evaluation of bulls and cows. J. Dair. Sei. 69:2963-2965. Wilk, J.C., 1988. Selection for yield in Jerseys. Paper presented at the UK Jersey society mee­

ting, pp 4.

61

Synthesis of the 1st session

E. P. Cunningham

Department of Genetics, Trinity College - Dublin University, Dublin 2, Irl

I feel that the most useful response to the four important papers presented this morning is to select a particular theme from each one. and to amplify it. My intention is to highlight a few important conclusions of general relevance to both the past and the coming decades in European animal science.

Changing nature of public responsibility in animal breeding

Dr Bichard has reviewed the evolution of the last twenty years in livestock improvement. When we look back to the beginning of that period, we find that in practically every country in Europe, and particularly for cattle and pigs, genetic improvement programmes were mainly the responsibility of governments. Ministries of Agriculture either conducted the testing and selection programmes, or they closely supervised and regulated, and often paid the cost of programmes run by producers' organisations. Today, all that has changed. Apart from the general tendency for reduced government intervention in economic affairs, there are some cogent reasons why such closely controlled programmes are no longer appropriate.

The first is the technical and structural evolution within farming itself. In general, there are half as many farmers now as there were then. In pig production, in many countries, there are perhaps only 10-20% of the numbers there were two decades ago. Those farmers who now manage Europe's livestock resources have better economic resources, and are better educated in all the technical skills that they need. There is therefore less requirement for government to act on their behalf.

Secondly, the organisations and companies that manage livestock schemes are now immea­surably stronger and more selfreliant than before. In the cattle industry, these are mainly producer owned artificial insemination organisations, while in pig production, they tend to be private breeding companies. Even where government programmes remain active, there are now very dynamic competitors for the role of managers of livestock improvement.

Thirdly, the European Community, representing 12 countries, has not alone committed itself to free trade in breeding animals and genetic material, but has taken very active steps in that direction. As part of the general deregulation of trade in 1992, the animal health and regulatory barriers which isolated national programmes within the Community will be largely removed. The competition which will inevitably follow will simply make the government programmes of twenty years ago no longer feasible.

While governments everywhere are rapidly, and properly, reducing their direct role in live­stock improvement, they still have very substantial responsibilities in this area. Indeed, the new order of things could make some of these responsibilities even more demanding.

The first is to ensure that in the more competitive world of the future, where many of the active organisations will be motivated mainly in terms of their own profitability, rather than by the perceived requirements of the producer, the public authorities have an increased respon­sibility to ensure that competition is regulated to the degree necessary to ensure the public interest. This primarily means keeping a watchful eye on the development of monopoly power. It also requires that the information on which producers can discriminate between the services on offer is adequate, honest and objective. This is a sort of 'bureau of standards' function.

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Genetic Value

'' Cloned Embryos \ (Stem Cell ':

Multiplication) /

/'Cloned Embryos 1 (Nuclear V Transplantation)

Gif Sexed

AI

-AV Cost (£/unit)

10 20 30 40 50+ 100+

Figure 1. Schematic representation of different breeding techniques in terms of relative costs and genetic values.

Secondly, the more rapid evolution of our livestock populations is going to increase the rate of disappearance of stocks which have evolved over periods as long as centuries in some Euro­pean countries. It is clearly in the public interest that appropriate conservation of these stocks take place, but none of the operators in a competitive world is likely to be able to afford the necessary investment.

Thirdly, while 'near market' research will largely be undertaken by the various breeding organisations themselves, the investment in precompetitive, longterm research of value to the industry will only be provided from public sources. These may be national, or supernational, as in the case of the European Community. Examples could include the mapping of the bovine and porcine genomes, and related work on molecular genetics; freezedrying rather than liquid nitrogen storage of semen and embryos; cloning and sexing technology; development of data banks and methodology for breeding value estimation across populations.

Technology — at a price

Drs Courot and Volland-Nail have presented an excellent review of the scientific and tech­nological successes of reproductive physiology research over the last 20 years. The triumph of science is all the greater when we consider it in the context of the evolutionary background of these populations and of these traits. Mammals go back 60 million years, and during all of that time evolution has very carefully crafted their reproductive patterns. The purpose of much reproductive physiology research today is to disrupt these patterns — to force sheep to lamb out of season, to persuade cows to have two calves.

Despite the scientific successes, we can see very variable success in the adoption of these techniques. The reason for the variability in adoption is obvious—each change in farm techno-

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logy is ultimately decided by a trade-off between increased cost and increased benefits. This can be illustrated for a range of existing and potential technologies for cattle reproduction (Figure 1). The base line for these techniques is natural service, which has a certain cost, and, on average, delivers a certain benefit in terms of genetic value. AI adds cost, but also benefit. In European dairying, the benefit is perceived to be large enough in relation to the cost that AI has largely replaced natural service. If semen could be sexed, further benefits would accrue, and this technique would be widely adopted, provided its cost, either direct or through reduced fertility, was not too great.

There is some disappointment that conventional embryo production has not more widely replaced AI. At present, it has managed to capture a fraction of 1 % of the AI market. The reason basically is that, while it costs more than ten times the average AI fee, the benefit it confers is the modest increment in genetic merit achieved through more intense female selection. This is only worth the extra cost in special circumstances, for example, in the breeding of young bulls for AI, where the benefit will ultimately be scaled up by widespread use of that bull. Again, sexing of these embryos is now beginning to be used and is likely to be widely adopted.

IVF embryos are cheaper to produce, but, because of the large number of females who must be donors, they have no genetic advantage over AI. If costs could be reduced to perhaps double the AI cost, this technology would have some prospects in special circumstances, e.g. for the production of twins. However, experience to date is not very encouraging.

The next generation of technology has already begun: the production of clones. Cloned em-byros produced by nuclear transplantation should have costs similar to IVF embryos. However, they could have substantial added value in genetic terms. While the technique has been suc­cessful on a limited scale, it is too early to say what its real cost will ultimately be, and also to know whether the corresponding benefits will be high enough to lead to widespread adop­tion. Somewhat beyond the range of current technology is the prospect of producing clones by stem cell multiplication. Intuitively, it seems that this should be a much cheaper technology. It would incorporate sex determination, and should provide a large increment in genetic merit. This technology could therefore eventually replace AI.

It is relatively easy to compare these reproductive technologies on common cost and benefit scales. The point being made is however a general one: all new technology competes with old technology, and its success is ultimately a matter of costs and benefits.

Are there limits to current technology? Where are the new challenges?

Drs de Boer, Bickel and Todorov have the advantage in writing their paper that they can draw on their remarkably useful book "Livestock Feed Resources and Feed Evaluation in Europe".

Research in nutrition and feeding has brought our level of knowledge, both in theory and application, to such a high level that it raises the question: have we reached certain limits? In the methodology of energy evaluation, we have moved from gross energy to metabolisable energy and now to net energy systems. Is this the end of the road, or is yet more sophistication waiting for us a decade hence? In practical feeding, we now have extraordinarily high conver­sion rates in efficient poultry, pig and dairy operations. How close are we to biological limits? A great deal of effort has been invested over the years in the documentation of the nutrient value of all available feedingstuffs. We now have good databases on this subject. Does that work need to be redone or is it simply a matter of maintenance of these databases in the years ahead?

My purpose in raising these questions is to ask the more general one: are there areas in animal science research where we should now regard the work as largely complete, and where we should perhaps shift resources into newer, and inevitably more difficult challenges? What are these challenges in the nutrition and feeding area? Europe produces some 400 million tonnes of cereals each year— its largest single agricultural commodity. An equivalent amount

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of energy is produced in the accompanying straw, and most of this is wasted. Unlocking the store of potential in lignin and cellulose seems to me a challenge worth a very large investment. Any success on this front would be a major advantage to the efficiency of European agriculture, but would also be an even more significant contribution to the challenge of ensuring world food security in the generations ahead.

Much of European livestock production is based on forage feed resources. The bottom line in the competitive world ahead for all production systems will undoubtedly be the world price of grain. If our livestock production is to remain competitive, then there is a real challenge in increasing the efficiency, and thereby reducing the real cost of forage as a livestock feed. In­deed, the very survival of farming systems in many parts of Europe could be determined largely by our success on this front.

On an even broader perspective, the real challenge for all of us is the inevitable doubling of world population in the next generation. All of the growth will take place in the developing countries. It will require a doubling of world grain production. Whether this can be achieved is a matter of debate. However, we may well face the situation in the intervening years that concerns of common humanity will require us to release grain from Europe's annual harvest, diverting it from our livestock systems to the even more urgent needs of human food supplies elsewhere in the world. Is there research which we should do to prepare the necessary adap­tation in our livestock feeding systems?

Who benefits from the present rapid evolution of European dairying ?

Professor Neimann-S0rensen in his paper expresses his longstanding concern that the narro­wing of objectives in European dairying may, in the long term, be undesirable. He backs these convictions with model calculations which show that a more balanced emphasis on animal health and reproductive efficiency may be economically sounder than continued emphasis on production per animal alone.

I share his concerns. However, we have a substantial conflict of evidence here. It is un­doubtedly true that millions of European dairy farmers in recent years have voted with then-feet by accepting a complete transition to American genotypes and pushing production per cow to levels that were unthinkable even a decade ago. Along the way, they have abandoned all concern for beef merit, and largely left health and reproduction to look after itself. Are they all misguided? A major experiment nearing completion at the University of Edinburgh strongly supports the economic justification for this general move.

Who ultimately is the main beneficiary of all this technological change? In the short term, dairy farmers clearly see themselves as benefiting, otherwise they would not implement these changes in policy. In the longer term (and nowadays that may be a matter of 5 to 10 years) these benefits are rapidly passed through to the consumer, so the real beneficiary of technolo­gical change is the public at large, which pays less in real terms for its food as the years go by. This dilemma for the agricultural industry is highlighted by the question of BST. Numerous experiments have now shown beyond doubt that administration of BST boosts milk output by 10-15%, and that, because maintenance overheads are spread Qver higher output, feed effi­ciency is improved by 5-7%. This gives a real reduction in the cost per kilogram of milk. Studies in America have shown that most dairy farmers will use BST if it becomes legally available. However, they are not happy about it. These studies have also shown that the enhanced competition will drive many smaller producers to the wall, and that the beneficiaries are first the companies, second the consuming public, and third the farmers. Indeed, for many dairy farmers, it is not a benefit at all.

The point I wish to make is not that safe improvements in technical efficiency can or should be impeded. It is simply that we need to be aware that technical change has costs as well as benefits. Often those who receive the benefits are different from those who pay the costs. All

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too often, the benefits are highlighted, while the costs are ignored. This has been very much the case in BST. In our development and application of science, therefore, honesty should compel us to be at least aware of the need for a full accounting of the costs as well as the benefits, and to recognise to whom these apply.

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Session II - Séance II - Sitzung II

Future challenges and questions

Les défis et interrogations du futur

Zukünftige Herausforderungen und Fragen

Chairman, Président, Präsident: A. Roos Co-Chairman, Co-Président, Co-Präsident: J. Coleou

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Management of animal material: adjustment to the economic evolution and to production constraints

F. Pirchner*, G. Schönmuth** & D. Flock***

* Technischen Universität München, 8050 Freising Weihenstephan, Germany ** Humboldt Universität Berlin, Germany *** Lohmann Tierzucht, Cuxhaven, Germany

Summary

It is assumed that future development will proceed without major interruption. If correct demands for more quality of food in dietary and variety in sensory respect will become im­portant. Problems are seen due to lack of flexibility of large breeding programs. Increased sen­sitivity toward use of medication in domestic animals should put a premium on genetic resistance to diseases. Behavior genetics could possibly help in providing animals with impro­ved adaptation to modern management.

The problem of maintaining genetic resources presents a dilemma insofar as any selection involves discarding of genotypes. Rare breeds kept for whatever reason should be considered as source for future developments. The nature of genetic variability keeps on eluding us. However, molecular genetics should help in getting closer to it.

Modern reproduction biotechnology will help in advancing progress although it is not by a magnitude more, rather improvements are of the order of 1/10-1/3. However, molecular genetics opens entirely new aspects even though commercial utilisation of transgenes will require considerable more work. Due to quotas secondary traits have received increased attention but then inprovement is hampered by low h2 or expensive recording. Key-words: genetic resources, rare breeds, genetic variability, biotechnology.

Résumé

Il est généralement admis que les perspectives de développement à l'avenir se dérouleront sans interruption majeure. Alors que l'on reconnaît qu'une demande plus affirmée se manifestera davantage à propos de la qualité des aliments et de leur diversité gustative, on voit se poser des problèmes en raison du manque de flexibilité des grands programmes d'élevage. Une prise de conscience accrue de la part du public à l'égard de l'administration de produits pharmaceu­tiques aux animaux de ferme devrait mettre en valeur la résistance génétique des animaux à la maladie. La génétique en matière de comportement pourrait contribuer à donner aux ani­maux un meilleur pouvoir d'adaptation aux exigences de la gestion moderne.

Le maintien des ressources génétiques pose un dilemme dans la mesure où toute sélection implique l'élimination des génotypes. Quelle que soit la raison de leur préservation, les espèces rares doivent être considérées comme une source d'innovations futures. La nature même de la variabilité génétique ne cesse de nous éluder. Cependant, la génétique moléculaire devrait nous permettre de nous en approcher.

La biotechnologie moderne de la reproduction nous permettra d'aller de l'avant mais non pas à une grande échelle car les améliorations ne se chiffrent qu'entre 10 et 30%. Il n'empêche que la génétique moléculaire ouvre de nouvelles perspectives, bien que l'utilisation commer­ciale de transgènes nécessitera encore de gros efforts, en raison des quotas, les critères secon-

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daires ont fait l'objet d'une attention accrue, mais l'amélioration est entravée par la faible héritabilité ou par de coûteux moyens d'observation. Mots-clés: Ressources génétiques, espèces rares, variabilité génétique, biotechnologie.

Breeding objectives

The scenario against which these deliberations are to be seen assumes continuous economic development which implies further increase in prosperity in Europe and in the industrialized world (WI), further population increase in the third world (Will) which entails either further economic stagnation or slow progress.

In the WI it is expected that the consuming population will favor increased differentiation of products, show increased concern for the health aspects of food and will be increasingly concerned about animal welfare.

The consciousness for food quality should encourage production of speciality goods. This in a way is against the modern trend to large scale production, processing, and marketing but it may be assumed that market forces will help to bring about the diversification desirable for the consumers and thus open niches for the producer.

As examples I would briefly mention cheese making quality of milk and marbling of meat. In many countries milk is still paid with little attention to its composition, tacitly, assuming that unalterated herd milk will have roughly constant composition. This may be hue when cattle in a region have uniform genetic composition. However, the recently available data on milk composition — fat, protein, casein — show that considerable population differences exist which should affect the cheese yield to a considerable extent (Larsen, 1972; Graml et al., 1985).

Even more, investigation of milk with different proteins has shown that there exists a pronounced difference between cheese making properties of milks with equal casein content (Mariani et al., 1976; Marini et al., 1982; Schaar, 1984). Breeders are concerned about the lack of price differences between milks with different proteins. More, milk will be utilized for different products and we can expect dairy plants to discriminate between milks for different types of production. Without this, breeding for certain qualities will be difficult to justify.

Another example for such problems could be the increased dissatisfaction with quality of pork (or beef). The aversion towards fat has resulted in successful efforts of swine breeders to reduce fat in pigs, pioneered by Danish breeders and culminating in the utilization of the 'halo-thane' gene from Pietrains. However, to many consumers pork quality has suffered and recent efforts aim at increasing marbling of pork as well as improving the fat quality in it (Schwörer et al., 1989).

I think that both situations could be handled successfully by breeders if it is possible to give the correct signals i.e. if payment reflects the consumer assessment. In view of the tendency of large scale marketing and its preference for uniform lots this will be not easy to achieve.

The public concern over health will increase. Therefore composition of diet will receive increasing attention. Most or all of dietary cholesterol is in food of animal origin. Attempts to lower it have been successful to some extent. E.g. in quail egg cholesterol content has been reduced by selection but at the expense of reduced hatchability. It may be necessary to make serious attempts in this direction, i.e. to modify the composition, in the direction which makes the product more acceptable if certain animal products are to retain the favor of the consuming public. Suggestions which involve far more severe changes in a biological sense have been made with regard to milk sugar removal (Mercier, 1986), or prevention of its synthesis in the mammary gland. In view of the comparatively small changes during domestication which barely or not at all involve qualitative alteration of animal products, it appears questionable whether such a profound change of the physiological processes is attainable in non-evolutio­nary time horizons.

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The different expectations and demands from animal products can be seen in the framework of genotype x environment interactions with imperfect genetic correlations between perfor­mance in different economic niches. Given that such differentation of demand will be reasonably stable, breeding programs can be organized to meet it. Of course such programs would have to be on a smaller scale than our national improvement schemes and the MOET nucleus approach or some modification thereof would have advantages of greater flexibility. However, knowledge of genes affecting a trait could permit also larger populations to cater for individual demands. E.g. an AI station could use bulls transmitting the gene for K-CnB in cheese producing areas and use other bulls in liquid milk areas. Analogous reasoning could apply to pig breeding with regard to the halothane gene. However, apart of the latter two exam­ples, development of competitive stock will take much time which may exceed the 'economic time' permitted. In such situations consideration of other breeds which have the desired traits may be advisable.

In today's production, disease is frequently prevented or cured by prophylactics/therapeu­tics although eradication is successfully employed. Apart from the recurring costs of drug ad­ministration residues in food cause problems. Therefore genetic disease resistance would remove these in addition to the more important effects on direct disease prevention. It should be mentioned that drug residues are no problem after vaccination, of course.

We are all aware of the resistance against Marek's disease which MHC haplotypes confer to chickens, of the effect of lacking receptors for E. coli-K88 on diarrhea in piglets. The MHC complex has effects on resistance to coccidia (Clare et al., 1988) and resistance to the avian bronchitis virus appears to be influenced by a locus outside this genetic region- (Bumstead et al., 1989). Salter & Crittenden (1987) succeeded to insert the envelope gene of an ALV virus making the birds resistant to infection by virus of the same type. Mastitis in cattle, resp. its occurence, reflects considerable quantitative genetic variation (Duda & Pirchner, 1989). There are also indications of involvement of major genes (M-blood group, BoLA). Thus there exists opportunity for genetic changes.

It appears that for some species/types of animals at least, the ability to deal with disease deteriorates. E.g. highly selected broiler strains seem to be less immunoresponsive and more susceptible to pathogens (Gross & Siegel, 1988). In cattle resistance to mastitis is negatively correlated with genetic merit for milk production (Duda & Pirchner, 1989). The question arises whether there shouldn't be selection for a general resistance to all or at least to the majority of diseases. However, work with poultry indicates that resistance to virus is largely independent of resistance to bacterial and coccidial infection (Gross & Colmano, 1971). If this can be extrapolated it would appear that selection for overall resistance is not possible and breeding would have to concentrate on resistance to the most damaging disease(s), where no other pro­phylaxis is available, such as was the case with Mareks disease before 1970.

The public shows increasing sensitivity to large animal production units and housing and management practices which go with these. In some European countries cage management of poultry has been outlawed. The question remains whether animals cannot be adapted to certain types of confinement and whether such an approach would not alleviate the apparent lack of well being of domestic animals. E.g. comparison of an unselected control strain with commer­cial layer strains revealed a genotype environment interaction where under cage management differences were much larger in favor of commercial strains than under floor management (the commercial strains were assumed to be selected in cages). If the public demands a return to some kind of floor management, disease problems such as coccidiosis may reappear and genetic resistance to these may receive renewed urgency since coccidiostatics are not allowed in layer feed.

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Cost reduction

In European countries with chronic overproduction, in particular of milk, quotas have been introduced which make an increase in milk produktion per individual farm uneconomical. Similar restrictions could be envisaged for other commodities should comparable situations arise. Quotas have a profound effect on the economic importance of the individual traits relative to each other (Fewson & Niebel, 1986). In general, cost reduction will receive increa­sed attention. Traits affecting costs involve fertility and disease resistance, calving ease and feed efficiency among others. Fertility and disease resistance are notorious for their low herita-bility and at least fertility and mastitis resistance have unfavorable connexions with dairy merit. Their genetic improvement implies rather large sire progeny groups. Feed intake in contrast involves expensive recording and could be looked after in nucleus breeding schemes.

However, as alluded to above, major genes may be identified with respect to disease resis­tance and the rapidly increasing information on the human genome and its close homology with parts of the genome of domestic animals, may give a possibility of efficient selection. With regard to resistance to infectious disease development of safe, cheap and more effective vaccines by recombinant DNA technology will greatly help to reduce the disease burden (Kang, 1989). Also, selection of individual animals for fertility (Pirchner et al., 1984) may be amenable to laboratory tests.

The reaction to milk quotas differs between regions. In S. Germany farmers with dual pur­pose animals maintain numbers, reduce concentrate feeding and try to make up for lost milk sales by sale of valued feeder calves. In contrast, farmers in N. Germany decreased numbers of cows and emphasize their yield. Inlusion of beef merit in the selection objective hampers selection for milk yield by the negative connexion between the two (Pirchner, 1986).

As mentioned above we think that WI breeders concern about increase of production will be overshadowed by the need to improve quality and reduce costs. However, there is one item which in our opinion presents a real challenge to European breeders.

In Central and Northern Europe suckler herds generally yield insufficient revenue to cover cost of land and labor, but dairy cow numbers will continue to decline. Therefore, demand for feeder calves will increase which can be alleviated by more twins. The Booroola gene causes triple ovulations and births, and search for a homologue in cattle would seem justified. How­ever, attempts to select in conventional manner for increased twinning also yield results (Stolzenburg, 1990).

Genetic variability

Maintenance

The concern over maintainance of sufficient genetic variability seems to be unfounded at least on short or medium term. If and when considering 'simple' traits populations are sufficiently numerous and appreciable rates of progress can be achieved over fairly long time periods, vid. Enfield (1980) for Triboleum, Dunnington & Siegel (1985) for broilers, or on a commercial scale, the improvement of broiler weights over the past 30-40 years. However, this is not really long term and in case of broilers at least, deterioration of other traits such as reproduction and disease resistance has become evident. In case of turkeys three breeders provide 90% of the stock for commercial production and most of the broiler and layer breeding stock is controlled by less than a dozen breeders each. Most of these breeders will maintain reserves as insurance but certainly the genetic variability is dramatically reduced compared to what must be, or must have been, available in flocks of thousands of village breeders of the Win or 50 years ago in Europe and in the US. Similar but less extreme situations prevail in other farm livestock. From this point of view the maintainance of local breeds should be encouraged wherever they occur

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and whatever the purposes they are kept for. It should not be overlooked that the situation was never static but that the history of animal breeding reveals a dynamic situation where popu­lations were continually changed by selection and immigration but this required existence of variation.

From a more technical point of view, genetic variability can be maintained with fairly limi­ted numbers as long as family selection (progeny testing) is not domineering, vid. various horse breeds. In addition, if there are independent populations overall variability should be maintained. In dairy or dual purpose cattle where family selection is deemed necessary the emphasis in small populations should be on testing as many bulls as possible which entails their testing with fewer daughters than in traditional AI schemes. Natural service sires ought to be included wherever sufficiently many test daughters can be expected. Limited sperma reserves of such bulls permit their use as future bull sires. MOET nucleus herds have been advocated for such situations but these fail to overcome the problem of erosion of variability.

Nature of quantitative variability

The application of quantitative genetics has led to remarkable improvement of economic traits in domestic animals. However, in passing it must be mentioned that the improvement of broiler growth rate was largely achieved by straight mass selection. As for dairy cattle the genetic progress has remained less than expected (van Vleck 1986). Several causes for this shortco­ming have been cited — long generation interval, insufficient attention to the principal trait (yield) and others. /

However, there exists the possibility of asymmetric heritability. Few indications of it exist for cattle but for mice it has been demonstrated (von Butler et al., 1984) and Sheridan (1988) from a review of literature summarizes that in experiments with farm animal realized heritabi­lity seems to be less than estimated heritability when selection is for improvement. There are not too many such experiments but if this can be generalized it would have considerable con­sequences to planning animal improvement. Therefore the possibility of asymmetry of genetic parameters needs to be investigated more systematically.

The almost complete lack of knowledge of the genetics of quantitative traits has drawn some caustic comments (Lewontin, 1986). Nevertheless, it is highly desirable and of impor­tance to future progress to know more about the genetic architecture of these traits — what are quantitative genes? Several approaches seem possible. The random approach scans the DNA for markers and attempts to correlate these with traits (Geldermann, 1988; Stranzinger, 1987). Marker assisted selection would logically flow from these developments (Zwieauer, 1980). Another approach could involve the physiology and biochemistry of a given trait and to track back to its genetic base. Our work on milk protein content (Graml et al., 1989) could be seen as an example of this approach. Certain proportions of the variance could be attributed to major genes, i.e. the casein and ß-lactoglobuline loci, in case of whey protein is was about half, and the remainder had to be considered as polygenic. Hanset (1989) published similar studies on meat proportion in carcasses due to the culard complex and to polygenes. The third approach rests on the extensive homology between species with regard to function and loca­lisation of genes. Extensive homology exists between rather distant species and the rapidly accumulating evidence from humans and mice could be profitably used when searching for genes in domestic animals (Womack, 1987).

On a further level the genetic causes of quantitative variability are less well known than is tacitly assumed. E.g. the structural milk protein genes account for less than 10% of the genetic variability of milk protein content. The exception is the lactoglobulin locus which accounts for about 50% of the variation of the whey protein (Graml et al., 1989) and thus it is a mega-phenic locus. In this instance the cause appears to be the variable length of the coding region. However, as for the other proteins variability of structural genes seems to play a minor role.

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It is possible that controlling regions determine the quantity of the products but research efforts are clearly needed to investigate this question.

Needless to say that knowledge of the 'genetic architecture' of traits would greatly facilitate selection. It should permit targeted introduction of genes or gene complexes which are missing in a population and it could/would permit selection of young breeding animals without having to wait for their own performance or progeny test. Gene transfer via molecular techniques could utilize its full potential only with this knowledge.

As indicated before transgenic techniques can only utilize their full potential when genes are known with regard to their function, their localisation.

Methods for improvement

Reproduction technology

Im monoparous species genetic progress is impeded by few offspring of females. Develop­ments in reproduction technology have opened possibilities for improvement. These are, in increasing order of sophistication, multiple ovulation, in vitro maturation (IVM) and fertiliza­tion (IVF) of Oozytes, embryo culture (EC), embryo sexing, embryo splitting and nuclear trans­fer which all require embryo transfer (ET). IVM, IVF and EC combined promise the possibility of large scale production of embryos the cost of which could be a fraction ( 1/5) of that of pre­sently procured embryos (Woolliams & Wilmut, 1989). .'

While at present embryo splitting results in monozygous twins, perfection of nuclear transfer will open the possibility of large clones (Willadsen, 1986; Modlinski et al., 1990).

As to the scope of these techniques for animal production one must differentiate between their effects on genetic improvement and their application in production technology. To discuss this first: if the ET costs can be substantially reduced it can be used to produce commercial cows and/or to transfer male beef or even double lender embryos into their uteri. This would benefit dairy and beef breeds and penalize dual purpose cattle.

The role of MOET in genetic improvement is presently limited to produce multiple progeny from elite females and thus to increase the selection intensity on the cow-to-bull path in otherwise conventional AI breeding programs. The increase in genetic advance relative to that of traditional systems is modest but it will be dramatic if it can be extended to the whole herd (Land & Hill, 1975). If we assume somewhat naively a futuristic situation, that the techniques mentioned permit to produce embryos in numbers comparable to those of sperma portions available from AI bulls, this would double the genetic progress.

In view of the presently rather high costs of ET, Nicholas & Smith (1983) suggested use of MOET in nucleus herds. Rates of genetic progress can be considerably greater than in con­ventional AI progeny test schemes. Various hybrid schemes between MOET nucleus and AI progeny testing have been suggested and have begun to operate (Fewson, 1988). They combine advantages of MOET nucleus such as a larger number of offspring per female and short gene­ration interval with the high accuracy from progeny tested bulls. The necessarily fairly small populations in MOET nucleus schemes and the predominating family selection leads to intolerably high rates of inbreeding and lower selection intensities than in large populations and computer simulations have indicated 20 to 30% lower response than predicted which brings genetic progress of MOET nucleus schemes close to that of conventional programs (Jansen & Schlote, 1988). However, advantages of nucleus herds with regard to measurement of additional traits eg. feed intake, and better control of selection would remain.

Cloning on a large scale permits replication of the total genotype with all beneficial epistatic and dominance effects. Heritabilities in the wide sense as estimated from identical twins are relevant here. However, for genetic improvement segregating progeny must be reproduced to which only the additive effects will have been passed on. Woolliams (1990) showed that clo-

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ning adds little if any advantage to MOET nucleus schemes and by implications to regular AI schemes, as long as numbers of animals to be manipulated are limited. Cloning can increase numbers of expressions of a given genotype which would be of value for lowly heritable traits but it also reduces numbers of tested genotypes and thus aggravates the inbreeding problem.

One should consider MOET nuclei not solely for purebreeding. They could be employed to produce hybrids among two nuclei which would alleviate somewhat the inbreeding problem.

Indirect predictors of genetic merit

For sex(female)-limited traits genetic improvement could be facilitated by direct ascertainment of the male genetic merit, either through its genes at quantitative trait loci (QTL), genes closely linked to these or through physiological traits. Use of markers to identify QTL and ensuing selection has been proposed first by Geldermann (1975) and Kashi et al. (1990) and Smith & Simpson (1986) have shown that its advantages rest very much on the extent of polyallelism at the marker loci.

The diagnosis of superior breeding animals can also be attempted via biochemical means (Gui et al., 1986; Sejrsen & Lovendahl, 1986).

Markers or biochemical criteria would decrease the pressure on numbers by reducing the need for very accurate progeny testing of basically all potential bull candidates. Thus such procedures could help in maintaining sufficient genetic variability.

Gene transfer /

Undoubtedly methods will be improved in particular if embryo stem cell transfection is further developed. Important aspects would be the screening of stem cells or resulting embryos for successful integration and expression of genes, undesirable mutations and sex. Testing proce­dures for the resulting progeny will have to be developed and adopted before widespread use of transgenic animals. The effects of genes may differ between populations as Hartmann (1988) reported from B21 gene which conferred Marek resistance to purebred but not to crossbred chickens.

While in the WI the efforts should be concentrated very much on cost reduction and product quality, in Win efficiency in a general sense will remain of utmost priority and of special importance. Different from the WI, to Will disease resistance and heat tolerance and for rumi­nants at least, ability to utilize low quality feed are of great importance. It appears that the latter two are antagonistic to some extent to high performance potential either for milk or for growth. As to disease resistance the genetics of trypanosomiasis tolerance appears to be of utmost urgency. It is hoped that utilization of newly available knowledge of molecular genetic will facilitate solutions.

In the temperate zones many breeds and strains are relagated by the major breeds to minor roles. Yet they may harbor potentials for W III, either as pure breeds or, more likely, as partner breeds in crosses. It appears urgent to engage in a more systematic testing these little used genetic resources in Will countries.

We have not considered the possible differences in problems and approaches in the countries with centralized planning. Even though at present efficiency of production has a higher priority than in WI it recent developments suggest that they will approach rather fast WI and then face very similar problems.

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References

Bumstead, N., Huggins, MB. & Cook, J.K.A., 1989. British Poultry Science 30:39-48. Duda, J. & Pirchner, F, 1989. Züchtungskunde 61:334-346. Dunnington, E A. & Siegel, PB., 1985. Theoretical Applied Genetics 71:305-313. Fewson, D., 1988. In: Weniger, J.H., Horst, P. & Iritani, A. (Ed.): Symposium of Biotechnology

Animal Breeding. Berlin, p. 158-169. Fewson, D. & Niebel, E., 1986. Züchtungskunde 58:4-20. Fries, R., Beckmann, J.S., Georges, M„ Soller, M. & Womack, J., 1989. Animal Genetics 20:

3-29. Geldermann, H., 1975. Theor. Appl. Genet. 46:319-330. Geldermann, H., 1988. In: Weniger, J.H., Horst, P. & Iritani, A. (Ed.): Symposium of Bio­

technology Animal Breeding. Berlin, p. 118-124. Graml, R., Buchberger, J., Klostermeyer, H. & Pirchner, F., 1985. Zeitschrift für Tierzüchtung

und Züchtungsbiologie 102:355. Gross, WB. & Colmano, G., 1971. Poultry Science 50:1213-1217. Hanset, R., Michaux, C, Leroy, P. & Detal, G., 1989. Ann. Med. Vet. 133:89-114. Hartmann, W„ 1988. In: Weniger, J.H., Horst, P. & Iritani, A. (Ed.): Symposium of Biotech­

nology Animal Breeding. Berlin, p. 137-145. Jansen, G. & Schlote, W., 1988. In: Weniger, J.H., Horst, P. & Iritani, A. (Ed.): Symposium of

Biotechnology Animal Breeding. Berlin, p. 170-179. Kang, C. Yong, 1989. Animal Biotechnology. M. Moo-Young, ed., Pergamon Press, New York,

p. 39-63. Kashi, Y, Hallerman, E. & Soller. M., 1990. Anim. Prod. 51:63-74. Lewontin, R.C., 1977. Proc. Int. Conf. Quant. Gen. 55-62. ISU Press. Mariani, P., Lossi, G., Russo, V. & Castagnetti, GB., Grazia, L., Morini, D. & Fosse, E., 1976.

Sei. Teen. Latt. Cas. 27:208. Marini, D., Lossi, G., Castagnetti, GB. & Mariani, P., 1979. Teen. Latt. Cas. 30:243. Mercier, J.C., 1986. In: Smith, C, King, J.W.B. & McKay, J.C. (Ed.): Exploiting new tech­

nologies in animal breeding. Oxford University Press, p. 122-131. Modlinski, JA., Gerhäuser, D., Lioi, B., Winking, H. & Ilmensee, K., 1990. Development 108:

337-348. Nicholas, F.W. & Smith, C, 1983. Anim. Prod. 36:341-353. Pirchner, F., 1986. p. 153-164 in vol. 3,3 WCGALP, Lincoln, Neb. Pirchner, F., Zwieauer, D., von Butler, I., Claus, R. & Karg, H., 1983. J. Anim. Breed. Genet.

100:304-315. Salter, D. & Crittenden, LB., 1987. Poult. Sei. Ass. Abstr. Ann. Mtg. Schaar, J., 1984. Journal of Dairy Research 51:397. Schwörer, D., Morel, P. & Rebsamen, A., 1989. 40th Annual Meeting of EAAP, Dublin. Sheridan, A.K., 1988. Animal Breeding Abstracts 56:877. Smith, C. & Simpson, S.P., 1986. J. Anim. Breed. Genet. 103:205-217. Stolzenburg, U. & Schönmuth, G., 1990. Selektionsexperiment auf Zwillingsgeburten bei

Milchrindern. J. Anim. Breed. Gen. 107:16-32. Stranzinger, G., 1988. In: Weniger, J.H., Horst, P. & Iritani, A. (Ed.): Symposium of Biotech­

nology Animal Breeding. Berlin, p. 11-26. van Vleck, D„ 1986. Evaluation of dairy cattle breeding programs. 3rd World Con. Gen. App.

Livest. Prod. 9:153-164 von Butler, I., Willeke, H. & Pirchner, F., 1984. Genetical Research 43:191. Willadsen, S.M., 1986. Nature 320:63-65. Woolliams, JA., 1989. Anim. Prod. 48:31-35 Woolliams, JA. & Wilmut, I., 1989. Anim. Prod. 48:3.30. Zwieauer, D., 1980 n.2. Adv. in Anim. Breed. Gen. Paul Parey Hamburg.

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Gestion des ressources alimentaires et conséquences sur la localisation géographiques des activités d'élevages

C. Beranger

Institut National de la Recherche Agronomique, Direction du Développement Agricole, 147 rue de V Université, 75007 Paris, France

Summary

Management of feed resources will closely depend on the general choice of Society as a whole for agriculture, environnement and development of the various peoples of the world.

Scientific and technical progress, increasing industrial utilisation of farm products will bring new food resources (from biotechnology, by-products...) and improved capacity of ad­justing the nutrient supplies to production objectives.

International exchanges will probably continue to increase but it must not be at the expense of the Third world. The intensification of production and utilisation of food resources, the concentration (in size and location) and specialisation of animal production farms will be re­stricted by the environnemental preservation, by the necessary harmonious lancrmanagement, the qualitative requirements of consumers and popular apprehension of certain new products and practices.

Animal production will probably recover its fundamental role in the management of land and of natural ressources and also its function of mediation between man and biosphere. The improvement of our capacities to build and manage animal production systems, adapted to va­rious ecological, farming, economic and social conditions will be essential to the future. This will lead to maintaining the optimum utilisation of food ressources, the farm competitivity and a good management of land and environment. All these various problems are examined and discussed in this paper. Key-words: livestock, feeding, land, environment, management, production systems.

Résumé

La gestion des ressources alimentaires dans le futur va étroitement dépendre des grands choix de la société de demain par rapport à l'agriculture, à l'environnement, au développement des divers peuples de la planète.

Les progrès scientifiques et techniques, les utilisations industrielles croissantes de produits agricoles apporteront de nouvelles sources alimentaires (biotechnologie, sous produits...) et une meilleure capacité d'ajuster les apports nutritifs aux objectifs de production recherchés.

Les échanges internationaux continueront sans doute à se développer mais ne pourront se faire au détriment du Tiers Monde. L'intensification de la production et de l'exploitation des ressources alimentaires, la concentration (en taille et en localisation) et la spécialisation des élevages se trouveront limités par la préservation de l'environnement, la nécessaire gestion harmonieuse du territoire, les exigences qualitatives des consommateurs et les inquiétudes des populations suscitées par certains produits ou certaines pratiques.

L'élevage retrouvera sans doute son rôle essentiel dans la gestion du territoire et de ses ressources naturelles et de sa fonction médiatrice entre l'homme et le milieu. L'accroissement de nos capacités de construire et gérer des systèmes d'élevage adaptés aux différentes condi­tions écologiques, agronomiques, économiques et sociales sera essentiel dans l'avenir. Cela

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permettra de maintenir à la fois l'utilisation optimale des ressources, la compétitivité des élevages et la gestion des divers milieux et territoires. Ces différents aspects sont examinés et discutés dans ce texte. Mots clés: animaux, alimentation, territoire, environnement, gestion, avenir, systèmes.

Introduction

Proposer des perspectives pour l'avenir sur la gestion des ressources alimentaires est un pari difficile dans un contexte écologique, économique et sociologique en pleine évolution.

On peut regarder l'évolution récente dans le rétroviseur et prolonger les tendances lourdes permanentes, corrigées des tendances actuelles. On peut aussi prendre largement en compte les changements qui s'imposent aujourd'hui dans la Société et considérer qu'ils seront domi­nants. De toutes façons, c'est maintenant au niveau de toute la planète en fonction des grands choix de société qu'il faut envisager l'avenir pour en tirer les conséquences sur notre Europe et sur la localisation future des activités d'élevage utilisant les diverses ressources alimentaires et les divers territoires.

Il faut partir des acquis scientifiques et de leurs applications au cours des dernières décennies pour prolonger d'abord les évolutions passées, puis s'interroger sur leurs limites et sur les con­traintes nouvelles qui s'imposent afin d'éclairer les tendances du futur.

La poursuite des tendances antérieures

Intensification des productions

Depuis quarante ans, pour accroître la productivité par travailleur, on a cherché à accroître sans cesse et en intensifiant la production animale par tête, par hectare et par unité de capital investi. Si l'intensification de l'utilisation du sol risque de se réduire notamment dans certaines zones, l'accroissement de la productivité du travail et des capitaux devrait se poursuivre.

Cela se traduit par une amélioration continue de l'efficacité alimentaire, par un accroisse­ment de la part des fourrages annuels (maïs, betteraves...) et des aliments concentrés dans l'alimentation des herbivores. Cela à entraîné également l'accroissement de la taille des élevages impliquant une mécanisation et une organisation de la récolte, du stockage et de la distribution des aliments, au prix d'une augmentation sensible des investissements. L'impor­tance des capitaux investis exige en retour une croissance continue de la productivité des élevages.

Diversification des ressources alimentaires

Plus récemment, on a vu s'accroître considérablement les échanges internationaux et les res­sources alimentaires se diversifier davantage à partir de produits exotiques et de sous produits industriels transportés à travers le monde.

Ces nouveaux produits alimentaires n'étant pas soumis aux organisations de marché de la Communauté Européenne ou mondiale ont pris une part croissante du marché au détriment des céréales tandis que les équilibres économiques et politiques du commerce mondial laissait au soja une place dominante comme source de protéines. Pour lutter contre cette prééminence du soja, des productions d'aliments riches en protéines ont été développées, dans de nombreux pays, en France en particulier (oléagineux: colza, tournesol, protéagineux: pois, feverolles, luzerne déshydratée).

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Efficacité croissante des productions animales

Les possibilités d'amélioration de l'efficacité des plantes et des animaux apparaissent encore considérables et les progrès dans ce domaine devraient se poursuivre dans le but de continuer à fournir aux consommateurs des produits animaux abondants, divers et bon marché.

Les potentiels génétiques de production actuels sont encore loin d'être valorisés et les limites à l'accroissement de ces potentiels sont sans cesse repoussées par les progrès de la génétique quantitative et de la génétique cellulaire et moléculaire. Le génie génétique en pro­duction végétale et animale peut, à terme, modifier bien des choses.

L'ajustement des apports alimentaires et des rations aux besoins des animaux et aux objec­tifs de production s'améliorera encore notablement avec les progrès de la nutrition (régulation de l'ingestion, physiologie digestive, métabolisme) et de la modélisation en nouveaux systè­mes, mobilisant des bases de données de plus en plus précises et complètes. Le choix et la combinaison des ressources alimentaires qui fait déjà l'objet d'une gestion très rationelle et performante sera sans doute encore plus adapté et facilité par ces progrès en perspective.

L'essor des biotechnologies

L'amélioration de l'efficacité des productions animales bénéficiera certainement de plus en plus des progrès des biotechnologies.

En nutrition on peut voir se développer la production d'acides aminés de synthèse, de vita­mines, d'enzymes, de bactéries et protozoaires modifiés permettant une meilleure transforma­tion des aliments et une fourniture en nutriments bien adaptés. On devrait parvenir à mieux valoriser les parois végétales et des substances diverses issues des transformations industrielles des produits végétaux.

Le génie génétique et la sélection des plantes permettra de fournir plus rapidement qu' aujourd'hui des variétés nouvelles dont la valeur nutritionnelle et hygiénique sera améliorée et adaptée à tel ou tel type d'animal ou de production.

Les biotechnologies également fourniront de plus en plus de substances capables d'orienter les métabolismes dans les sens recherchés: les activateurs de croissance, de lactation tels que la somatotropine, les immunisations contre l'action de certaines hormones, toute une gamme de possibilités d'actions sont en voie de développement. On peut aussi espérer trouver les parades aux divers troubles nutritionels engendrés par l'évolution des modes d'alimentation.

Tout cela permettra de réduire encore les besoins en aliments par unité de produit animaux et de diversifier les ressources alimentaires potentielles.

La mécanisation, la robotisation et l'informatisation

Les progrès en matière de récolte, conservation, reprise, mélange, distribution des aliments se poursuivront sans doute. Ils s'accompagnent d'une capacité croissante d'adaptation à des conditions et tailles d'élevage variées, assurant souplesse et simplicité des travaux. Les rations complètes, les distributions réglées ou programmées, devraient se développer. L'amélioration des systèmes de surveillance, de manipulation des animaux, la possible robotisation de la traite s'ajouteront aux progrès précédents pour accroître encore la productivité du travail des éleveurs. Simultanément l'essor de l'informatique à la ferme permet de contrôler et de gérer de façon de plus en plus rapide et précise l'alimentation et la conduite des troupeaux.

La spécialisation et la concentration des élevages

La conjonction de toute les évolutions précédentes ont entraîné une concentration régulière des élevages et leur spécialisation croissante.

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La concentration s'est opérée à la fois au niveau de la taille des élevages et au niveau de leur localisation sur le territoire. Cela a été très net pour la produciton avicole qui est devenue 'industrielle' hautement spécialisée, intégrée dans une filière très productive et très organisée. La diversification des productions avicoles (dinde, canard...) n'a pas modifiée cette tendance.

Les autres productions dîtes 'hors sol', la production porcine, la production de veau de batterie ont suivi la même évolution. La taille des ateliers porcins s'est sans cesse accrue et les 3/4 de la production sont concentrés dans les pays ou régions du Nord Ouest de l'Europe.

En France, la production laitière, dans une moindre mesure, s'est également concentrée dans les zones de l'Ouest et du Nord-Est favorable à l'herbe et au maïs. Une grande part de la production de viande, liée au troupeaux laitiers a suivi la même tendance. Les troupeaux laitiers se sont partiellement maintenu dans les zones centrales et de montagnes en raison de mesures politiques structurelles (indemnités spéciales montagne en particulier) ou de régulation du marché (quotas).

La spécialisation et la politique des prix en matière de production végétale de grande culture, ont entraîné de longue date un abandon de l'élevage dans les zones de plaines céréalières, y compris des élevages hors sol utilisateurs de céréales. Cela est surtout observé en France mais aussi dans plusieurs pays d'Europe.

La diversification des ressources alimentaires utilisées, l'importance prise par les aliments importés (soja et PSC) entraînent une concentration des élevages vers les zones portuaires (Pays-Bas, Belgique, Bretagne) accentuant encore les tendances antérieures de délocalisation des élevages. Cette évolution très nette pour les productions hors sol s'est étendue aux vaches laitières avec l'accroissement de la part des aliments concentrés dans les rations notamment dans les pays d'Europe du Nord ou le maïs ensilage ne peut guère se développer.

Le développement des filières de production — industrie des aliments, ateliers et exploita­tion d'élevage, industrie de transformation et grande distribution — s'effectue principalement dans les zones de concentration d'élevage, et cela accentue en retour la nécessité de développer les élevages dans ces zones.

Toutefois, lorsque l'alimentation peut être simplifiée (céréales + protéagineux en farine) à partir de ressources locales, des ateliers importants et modernes peuvent se développer en zone de culture, comme on l'observe dans le cas de la poule pondeuse dans le bassin Parisien.

Seules les productions de viande bovine et ovine spécialisées sont demeurées très liées aux ressources fourragères. Si elles sont souvent restées localisées dans les zones traditionnelles de production herbagère ou en zones sèches, les évolutions récentes ont principalement résulté de mesures politiques. La limitation de la production laitière par les quotas, en libérant des surfaces fourragères, entraîne un développement des troupeaux de bovins et ovins à viande en zone laitière. Les règlements ovins de la CEE ont favorisé le développement des troupeaux ovins Britanniques et la récession des troupeaux ovins en France et leur maintien dans les pays de la zone méditerranéenne.

D'une manière générale, les productions animales insérées dans des filières organisées, de plus en plus intensives et utilisatrices d'aliments concentrés se développent préférentiellement dans certaines régions au détriment des zones qui voient stagner ou décroître leurs productions et dont les ressources naturelles sont de moins en moins exploitées.

Des ressources moins chères et plus variées

Dans ce contexte général d'évolution continue, les inflexions concernant l'utilisation des diverses ressources dépendront beaucoup de deux grands facteurs: • Les prix de marché des productions végétales. Le marché excédentaire par rapport aux

besoins des pays solvables continuera à faire baisser les prix mondiaux, aux aléas climati­ques près, et facilitera les achats de matières premières sur ce marché. A cela peut s'ajouter une réduction des prix internes aux pays ou à la Communauté Européenne, dans la mesure ou les soutiens seront réduits (quantités maximum garanties) et où les gouvernements

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privilégieront le soutien aux producteurs plutôt que le soutien des prix des produits. Des céréales et oléoprotéagineux bon marchés faciliteront leur utilisation par les animaux.

• Les possibilités d'utilisation industrielle des productions de grandes cultures (énergie, nouveaux matériaux, chimie...). Leur développement dépend des technologies mais sup­pose surtout des prix assez bas, allant dans le même sens que précédement ; mais cela fournit parallèlement une source de souS-produits importante et bon marché, pouvant se substituer partiellement aux importations ou accroître la part des aliments concentrés divers dans les rations.

Ces phénomènes peuvent contribuer à localiser certaines productions dans les zones produc­trices et transformatrices de céréales et oléagineux au fur et à mesure que les investissements des filières animales auront été amortis, comme cela apparait déjà pour les poules pondeuses.

Les limités de cette évolution et les rémises en cause

Déjà, dans les années 70, l'évolution précédente avait été mise en cause par les crises pétro­lières, ou des événements tels que l'embargo américain sur le soja ou encore par l'émergence des mouvements écologistes. Des orientations vers une agriculture différente, plus économe et autonome, avaient été proposées. L'impact de ces faits est resté limité et les tendances lourdes ont largement prédominé. Aujourd'hui, les problèmes s'accumulent dans les pays industriali­sés, le l'Ouest et de l'Est, et dans le Tiers Monde et peuvent modifier largement le cours des choses. /

Trois grandes questions obligent à des révisions importantes dans les pays industrialisés: • La surproduction par rapport au marché solvable.

L'augmentation continue des productions entraîne des excédents qui ne trouvent pas de place sur les marchés solvables. La surproduction impose à la fois des mécanismes de régu­lations des productions (quotas, quanturns, quantités maximales garanties, retrait de ter­res...) et des baisses de prix des produits. Cela modifie l'intérêt respectif des diverses pro­ductions animales et végétales et des ressources alimentaires à utiliser et les localisations des productions.

• Les problèmes d'environnement et les exigences de qualité. L'amélioration de la productivité s'est accompagnée d'une utilisation croissante d'engrais, de phytosanitaires, d'additifs alimentaires, de médicaments et aussi de concentration des élevages et donc de leur déjections. Tous ces éléments sont, dans bien des cas, sources de pollution des eaux, des sols, de l'air et des aliments et sont souvent considérés comme tels par l'opinion publique. La maîtrise de ces pollutions impose une réduction raisonnée des intrants et des effluents ainsi que leur traitement ou leur dilution sur un plus vaste territoire. Les consommateurs sont de plus en plus sensibles aux qualités hygiéniques et nutritionnel-les des aliments, à leur diversité et aux qualités organoleptiques des aliments de haut de gamme. Les transformations requièrent en outre, des qualités technologiques diverses. Ces exigences limitent l'utilisation de certains additifs voire de certains aliments peuvent s'opposer à la recherche des performances et de l'efficacité alimentaire maximales. La sensibilité de l'opinion vis à vis du bien être des animaux, pour la qualité de leur vie et celle de leurs produits qu'on estime liée au mode d'élevage, entraîne également la nécessité de modifier les conditions d'élevage et d'alimentation dans certains pays. L'inquiétude des populations devant l'accélération du progrès, les risques liés à l'utilisation de nombreuses substances dont les effets à long terme ou indirects sont mal connus, ou encore devant les manipulations du vivant à travers le génie génétique, freinent ou retardent les évolutions qui peuvent résulter des innovations nombreuses qui apparaissent. Les com­missions d'éthiques, les analyses et enquêtes approfondies, les réglementations de plus en plus précises et sévères pour assurer la protection objective ou subjective des populations remettant de plus en plus en cause la poursuite des tendances antérieures.

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L'utilisation du territoire. L'élevage joue un rôle très important dans l'occupation du territoire notamment par les herbivores qui valorisent les surfaces toujours en herbe. La limitation des grandes produc­tions agricoles par la nouvelle politique agricole, l'accroissement continu de la productivité des surfaces agricoles, la diminution rapide et continue du nombre d'agriculteurs, le poids des investissements nécessaires à la reprise des exploitations, l'urbanisation croissante, tous ces facteurs concourrent à réduire les superficies utilisées par l'agriculture et l'élevage. La nécessité de maintenir un tissu rural vivant et peuplé, d'entretenir le territoire, d'assurer la qualité des paysages, d'éviter les friches etl'embrouissaillement, facteurs d'incendie, impli­quent l'occupation et l'entretien de l'espace rural. La prairie, l'élevage des herbivores y contribuent largement et devraient s ' accroître tout en évitant d'augmenter parallèlement les productions excédentaires. L'extensification de l'utilisation des surfaces fourragères, la gestion rationelle des territoires pastoraux et des zones sèches, la diversification des productions apparaissent nécessaires pour parvenir à assurer cet équilibre. Cependant, parallèlement à une extensification de l'utilisation des herbages, les problèmes de pollution dans les zones humides où les élevages sont concentrés, le coût des investis­sements en bâtiments d'élevage, la baisse des prix des ressources alimentaires, les facilités de transport pourraient entraîner un mouvement vers le Sud des productions animales, notamment de la production laitière à l'image du développement de celui-ci en Californie aux USA. Toutefois, ces problèmes propres aux pays industrialisés s'intègrent dans ceux beaucoup plus vastes et sans doute plus importants posés par l'équilibre général du monde. L'évol­ution démographique qui entraîne une stagnation de la population des pays industrialisés d'Europe et d'Amérique du Nord autour de 1 milliard d'individus et la croissance des autres pays de 4 à 5 milliards influencera fortement l'équilibre du monde et indirectement l'utilisation des diverses ressources alimentaires. L'accroissement des échanges interna­tionaux en produits alimentaires destinés aux hommes ou aux animaux, ne peut se faire sans cesse au détriment du Tiers Monde. Le développement de l'élevage à partir de la valorisation des ressources naturelles, com­plémentaires des cultures vivrières et des sous produits locaux, sa contribution à la fertili­sation et à la traction pour l'agriculture, le maintien de son rôle de capitalisation est nécessaire dans ces pays. S'il peut bénéficier des technologies nouvelles à condition qu' elles soient adaptées aux conditions et aux sociétés, ce développement peut interférer plus ou moins avec celui des pays industrialisés, à travers les échanges de ressources alimentaires et de produits animaux en fonction des rapports économiques et politiques qui s'établiront dans le futur.

Une nécessaire maîtrise et gestion équilibrée

Compte tenu de l'évolution des quarante dernières années et des diverses contraintes qui simultanément se renforcent et se conjugent, l'agriculture en général et l'élevage en particulier doivent retrouver dans nos sociétés les rôles multiples qu'ils doivent jouer, au delà de la moder­nisation et de l'industrialisation des productions animales.

Il s'agit de combiner à la fois la fonction de production très efficace et productive, l'insertion dans des filières de transformation et distribution capables de maîtriser les qualités et la diversité des produits, la préservation et l'amélioration de l'environnement et du territoire, le maintien d'un tissu rural vivant et acceuillant. Il faut aussi aider les autres pays et peuples à produire davantage et mieux. Cet équilibre complexe entre des objectifs en partie contradic­toires est à établir et maintenir dans les divers pays et zones. Les forces économiques sociales et politiques doivent s'affronter pour tenter de l'obtenir faute de quoi on laissera s'établir des

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déséquilibres profonds entre zones et secteurs de production, sources de dégradation et conflits pour le futur. Quels sont les principaux facteurs technologiques économiques et socio-politi­ques qui sont à mettre en oeuvre pour progresser dans ce sens?

Les fourrages et l'utilisation du territoire

Les fourrages représentent 50 à 80% de l'alimentation des herbivores et leur part dans l'ali­mentation ont tendance à se résuire progressivement. Les productions fourragères et tout particulièrement les prairies jouent un rôle fondamental dans la couverture et la protection des sols et des paysages. Elles sont et peuvent être utilisées à des niveaux d'intensification très variés et devraient maintenir ou retrouver toute leur place dans les ressources alimentaires.

Après un effort généralisé d'intensification de la production fourragère dans de nombreuses régions d'Europe, on devrait mettre au point, développer ou conforter des systèmes moins intensifs ou réellement extensifs sans modifier notablement les performances animales et en poursuivant l'amélioration de la productivité du travail et des investissements. L'accroissement des prairies perennes et de l'utilisation de légumineuses, la réduction raisonnée de fertilisants, l'utilisation complémentaire de surfaces de parcours, de prairies d'altitudes ou de zones humides permettent de bâtir de nouveaux itinéraires techniques adaptés à une utilisation accrue des surfaces disponibles. La mécanisation de la récolte du foin au grosses balles, la souplesse apportée par les possibilités d'enrubannage des balles (ensilage ou haylage), la réduction des objectifs de production à l'hectare redonnent au foin une place importante dans ces itinéraires.

Pour maintenir et développer des systèmes de production utilisateurs de surfaces, de nom­breuses améliorations techniques doivent être mises en oeuvre. Ce sont notamment celles qui permettent de mieux utiliser les parois végétales (sélection des plantes, nouvelles plantes fourragères, complémentation adaptée, additifs, traitements des foins et pailles, microbiologie du rumen...) ou d'améliorer et de mieux prédire la valeur alimentaire des fourrages ou d'accroître la souplesse de leur utilisation avec peu d'intrants.

L'amélioration génétique des plantes prairiales devra tenir compte de ces nouveaux objec­tifs d'adaptation plus grande au pâturage, à la souplesse d'utilisation, à la réduction des fumu­res azotées.

La gestion maîtrisée de surfaces diverses et hétérogènes par des systèmes d'élevage adaptés à la diversité et à la répartition de ressources fourragères, judicieusement complétées permet­tent d'utiliser des territoires qui seraient abondonnés et soumis à la dégradation du feu ou de l'érosion, ou à l'ensauvagement. La mise au point du développement de systèmes d'agrofo-resterie devrait permettre également de nouveaux équilibres entre productions animales et forestières et utilisation des territoires.

Ces possibilités d'évolution reposent sur des progrès technologiques, sur l'amélioration des méthodes de diagnostic et de gestion des surfaces, mais aussi sur les conditions économi­ques et socio-structurelles des élevages de demain.

L'évolution démographique des exploitants permet dans beaucoup de régions l'agrandis­sement des exploitations et l'utilisation de terres en voie d'abandon, si les coûts et conditions d'accès au foncier sont améliorés (marché des terres, fiscalité, structure juridique). La restruc­turation du foncier, les aides de la CEE à la jachère pâturée, à Intensification, à l'agrandis­sement des exploitations, aux pratiques respectueuses de l'environnement devraient favoriser ces évolutions (la volonté politique de mieux répartir les entreprises d'élevage sur le territoire pour réduire la concentration en effluents peut aussi y contribuer).

Cependant, la compétition entre les productions de viande obtenues dans ces élevages Euro­péen et ceux des pays très extensifs du nouveau monde ou de l'océanie peut freiner le maintien et le développement de ces élevages et de leur rôle dans l'occupation du territoire. Il faudrait alors que la collectivité finance davantage directement les services d'entretien du territoire et du paysage rendus par l'élevage pour compenser les handicaps économiques liés à cette fonction.

85

L'adaptation de l'animal au milieu

La possibilité d'utiliser davantage les ressources naturelles exploitées à divers niveaux d'intensification, implique qu'on recherche à nouveau des animaux adaptés aux milieux, par leur comportement alimentaire en particulier, plutôt que d'adapter sans cesse artificiellement le milieu à des animaux de plus en plus performants. Cela n'implique pas pour autant la réduc­tion systématique des potentiels de production mais l'adaptabilité des animaux et le recours aux ressources génétiques animales que nous devons conserver pour pouvoir les valoriser selon les besoins. En outre, l'amélioration des performances et l'adaptation comportementale au milieu rejoint également l'amélioration du bien-être des animaux dans les milieux très variés, depuis les milieux naturels quasi sauvages jusqu'aux bâtiments conditionnés.

Les progrès en ethologie animale permettant en particulier de fonder sur des bases nouvelles les rapports de l'homme et de l'animal en fonction des diverses conditions d'élevage joueront un rôle essentiel dans l'élevage du futur.

La spécialisation des types d'animaux en fonction des milieux et l'organisation des produc­tions entre zones complémentaires a déjà fait ses preuves dans certaines régions en élevage bovin ou ovin (élevage de races rustiques en zones difficiles, de croisement FI en zones inter­médiaires, engraissement des produits ou races très spécialisées en zones riches). Bien que complexe à réaliser, elle peut trouver une place dans le cadre d'élevages plus extensifs et d'uti­lisation plus rationelle du territoire.

L'utilisation des co-produits et sous produits

L'alimentation animale joue déjà un rôle essentiel dans la valorisation des co-produits et sous-produits de la transformation industrielle des produits végétaux. Ce rôle s'amplifiera sans doute encore avec l'accroissement des utilisations non alimentaires des produits agricoles, avec la volonté de réduire les pollutions d'origine industrielle, avec les facilités de transport et les progrès technologiques de triage, traitement, conservation des produits.

Cela entraîne un effort d'amélioration du co-produit, par les voies de la sélection végétale, de la production et de la transformation, égal à celui porté sur le produit principal. Des progrès considérables doivent être réalisés pour mieux identifier, caractériser, prévoir la valeur alimen­taire, la valeur hygiénique et les diverses utilisations possibles des produits, par des méthodes simples et rapides. L'amélioration de l'information et de sa circulation peut se faire à travers les bases de données fiables et réseaux constitués ou en formation. Grace à de nouvelles technologies, des formes humides peuvent recouvrir leur intérêt dans les zones de proximité des sources de production.

Ce développement s'inscrira de plus en plus dans le cadre d'une meilleure maîtrise, protec­tion et réglementation concernant l'utilisation de ces produits. Tout l'effort sur la valorisation des sous-produits doit être à la fois dirigé vers les pays industrialisés et les pays en voie de développement selon des voies adaptées.

L'utilisation des diverses grandes productions végétales

Les grandes sources d'énergie et de protéines en aliments concentrés seront d'autant plus utilisés que leur prix tendront à baisser ainsi que les coûts de stockage et de transports qui facilitent les échanges. Cependant, la différenciation des produits selon leur caractéristiques qualitatives et leur adaptation aux différents usages seront un des facteurs principaux d'une meilleure utilisation. Le contrôle de la variabilité croissante des produits et de la maîtrise de cette variabilité sous l'effet des progrès génétiques et des nouveaux itinéraires techniques moins intensifs et mieux adaptés au milieu, permettront de meilleurs ajustements aux locali­sations, conditions et objectifs de productions animales.

86

La combinaison de ces sources aux sous-produits et aux fourrages se fera à la fois pour amé­liorer l'efficacité alimentaire et réduire les coûts de production, mais aussi pour maîtriser les déjections animales, en réduisant notamment les fuites d'azote. Cela peut modifier des stratégies d'utilisation comme par exemple la promotion de l'association céréales — lysine industrielle dans l'alimentation du porc.

L'utilisation des additifs

Cette utilisation va se complexifier de plus en plus. Les progrès des biotechnologies vont sans cesse renouveler les substances, les activités possibles et leur usage sera de plus en plus recher­ché pour améliorer l'utilisation des fourrages de qualité variable, des sous produits, favoriser leur conservation et leur transport, réduire ou transformer les effluents d'élevage.

Les progrès technologiques ont ici toute leur importance pour le futur. En revanche, la protection du consommateur et des milieux naturels, l'ajustement aux évolutions des menta­lités de l'opinion publique, les réglementations de plus en plus sévères, contraignantes et uni­fiées contraindront à un accroissement des coûts de ces substances à une grande lenteur et prudence dans leurs applications. La recherche des substances xénobiotiques et des risques qu'elles peuvent entraîner ira en s'accroissant. Les progrès dans l'étude objective des écosys­tèmes biologiques, des écosystèmes sociaux et de leur relations seront essentiels pour gérer au mieux toute ces contradictions et conflits potentiels.

L'importance de la liaison entre qualité des produits animaux, modes et lieux de production

Face aux tendances qui visent à faire des agriculteurs et éleveurs, des producteurs de molécules que l'industrie recombine ensuite à des fins alimentaires, ou autres, pour satisfaire les divers besoins, la recherche de productions plus 'naturelles' est sans cesse réaffirmé par une part importante de nos sociétés industrialisées.

Il est indispensable de parvenir à une connaissance et une maîtrise accrue des caractéristi­ques qualitatives des produits en fonction des facteurs de productions, des itinéraires techni­ques, de culture, d'élevage, de transformation et de distribution et en fonction des localisations, des terroirs de production. Cela se combine ensuite avec les préférences alimentaires, les divers types de produits recherchés banaux ou fictifs, les images et symboles véhiculés par ces produits.

Beaucoup de régions, de systèmes de production peuvent trouver leur originalité et leur débouchés dans ces produits qui s'associent bien aux méthodes plus extensives, à une alimen­tation animale fondée sur les ressources naturelles au maintien de types génétiques adaptés à la protection de l'environnement, les zones de montagne sont déjà beaucoup progressé dans ce sens. Le cas extrême de l'agriculture biologique qui exclut l'usage de substances chimiques de synthèse correspond à cette évolution dont l'importance grandissante est difficile à évaluer pour l'avenir.

Des systèmes équilibrés, renouvelables (sustainables) se développeront sans doute dans l'avenir d'autant mieux que la maîtrise objective des qualités des produits pourra être obtenue et que les réglementations protégeront les produits et circuits originaux, les terroirs identifiés, les appellations d'origines.

L'importance de la gestion des systèmes d'élevage

La maîtrise équilibrée des facteurs écologiques, agronomiques, zootechniques, économiques et sociaux suppose de progresser beaucoup dans la compréhension et la gestion des différents systèmes d'élevage dans leur complexité et leur diversité. L'utilisation des bases de données alimentaires et des systèmes d'évaluation des apports et des besoins doit permettre une

87

adaptation de plus en plus souple aux objectifs de production animale. L'alimentation s'inscrit dans des modèles de plus en plus complets et précis d'élaboration des performances utilisables pour piloter selon des itinéraires de productions adaptés aux divers objectifs.

La modélisation de plus en plus élaborée des systèmes d'alimentation, des systèmes fourra-gers, des systèmes d'élevage au sein des exploitations et des régions permettra d'aider à la décision et à la gestion des ressources alimentaires, des troupeaux et des systèmes d'élevage.

Ceux ci devraient sans cesse pouvoir s ' adapter à la diversité des situations et à leur constante évolution. Ces approches de modélisation systémique permettent également de dépasser la seule gestion, les ateliers d'élevage ou les exploitations agricoles, pour considérer la gestion des filières de production et celle du territoire agricole et rural.

La gestion des ressources alimentaires, des troupeaux, la localisation et le rôle des activités d'élevage dans l'espace, se déterminent de façon interactive avec l'ensemble des acteurs concernés sur la base d'une capacité croissante de mobilisation et d'utilisation judicieuse des connaissances, des concepts et des données pour mieux décider. Cette capacité des hommes à bien utiliser ces connaissances, à gérer et décider le mieux possible sera largement aussi déterminante sur l'avenir de nos activités d'élevage que les progrès technologiques que nous pourrons réaliser.

La gestion des ressources alimentaires et la localisation des activités d'élevage qui y sont liées relève de phénomènes complexes qu'il faut aborder globalement alors que nous savons très mal le faire. Ils dépendent de décisions individuelles des exploitants et de décisions collec­tives prises à différents niveaux d'organisation.

De tout temps, les activités d'élevage ont été révélatrices et médiatrices des relations entre l'homme et son milieu (Vissac, 1978). Les transferts de ressources ou d'animaux entre lieux, l'adaptation des systèmes de production animale à la diversité et à la variabilité des ressources, l'exploitation des complémentarités biologiques ont permis au cours des siècles d'obtenir différents équilibres que la société industrielle met fortement en cause. Les déséquilibres survenus depuis quelques décennies nous lancent de nouveaux défis et réclament de nouveaux équilibres. Ils s'établiront selon les poids respectifs des forces qui s'exercent aux différents niveaux: • Le poids des marchés et des filières agro-alimentaires et industrielles désormais internatio­

nales, dans un contexte de concurrence de plus en plus forte; ils favorisent l'accroissement des échanges, les produits et procédés nouveaux, la spécialisation et la concentration des élevages, mais ils devront prendre de plus en plus en compte le coût des déséquilibres qu'ils suscitent.

• Le poids des populations locales, des consommateurs, de l'opinion publique à la recherche de l'utilisation optimum du territoire, de la protection de l'environnement, de la qualité et de l'authenticité originale des produits: ils favoriseront la valorisation des prairies, des fourrages et des ressources naturelles dans des systèmes plus extensifs, ils assureront la promotion de produits diversifiés et originaux et la rémunération d'activités de service par l'élevage.

• Le poids des pays en développement qui imposeront plus ou moins leur exigences d'appro­visionnement ou la concurrence de certains de leurs produits comme ressources alimentai­res ou produits animaux. Cela peut modifier sensiblement la place des diverses productions animales.

Les activités d'élevage jouent un rôle essentiel dans la relation de l'homme et de la nature que nos sociétés industrielles redécouvrent comme fondamentale. Si un nouveau 'contrat naturel' doit être passé entre l'homme et la terre pour retrouver les fondements du paysan et de l'éleveur (Serres, 1990), le jeu des seules forces économiques sera davantage relativisé.

Il faudra conjuguer l'amélioration des filières de production et la gestion harmonieuse de la nature et de l'espace au service des hommes, de leur besoins alimentaires, industriels et aussi socio-culturels.

88

Les progrès continus des sciences et des techniques devront servir cette double fonction, être finalisés et valorisés dans ce sens, être à usages multiples. Ils ne seront utilisés positivement que s'ils sont correctement mobilisés dans des systèmes de gestion de décision et d'organisa­tion capables d'être maîtrisés par les individus et la société.

Références

Beranger, C, 1989. Extensification: champs à découvrir. Initiatives rurales 7/8. 57-59. CCE, 1988. L'avenir du monde rural. Comics 88.501. Commissariat General au Plan, 1989. L'agriculture face à son avenir, groupe du plan 89.92.

L. Perrin. La Documentation Française 109 p. de Boer, F. & Bickel, H., 1988. Livestock feed ressources and feed evaluation in Europe. EAAP

Pub. 37. Livestock Production Science 19 No. 1. and 2. 407 p. de la Farge, B., 1988. La production porcine dans la Communauté Européenne. Journées de

la Recherche porcine en France 20:1-8. Hubert, B. & Girault, N. (Eds), 1988. De la touffe d'herbe au paysage: troupeaux et territoires,

échelles et organisations INRA Publ. Route de St Cyr Versailles 336 p. INRA, 1988. Alimentation des bovins ovins et caprins; Jarrige, R., (Ed.) INRA Publ. Route de

St Cyr Versailles. 47 lp. INRA, 1989. Alimentation des animaux monogastriques, porcs, lapins, volailles. 2ème éd.

INRA Pub. Route de St Cyr Versailles. 282 p. , Landais, E., 1987. Recherches sur les systèmes d'élevage question et perspectives, Versailles

INRA Doc. unité SAD Versailles 75 p. Poly, J., 1978. Pour une agriculture plus économe et plus autonome. Doc. INRA 65 p. Serres, M., 1989. Le contrat naturel. Bourrin, F. (Ed.). Talamucci, P. & Chaulet, C, 1989. Influence of contraints on the evolution of forage resources

in the Mediterranean Basin. 16th International Grassland Congress Nice France Vol. 3. Ed. AFPF Route de St Cyr Versailles.

Tirel, J.C., 1987. Valeur et limites des notions d'intensification et d'extensification dans l'ana­lyse de l'évolution des systèmes de production. CR Académie Agriculture. France 73(8): 83-95.

Vissac, B., 1978. L'animal domestique révélateur des relations entre la société et son milieu. Doc INRA 26 p.

89

Dynamics and diversity of animal production enterprises

G. Alderman

Department of Agriculture, University of Reading, Reading RG6 2AT, United Kingdom

Summary

The trend towards a greater proportion of livestock production units being of larger size will continue, depending on existing country farm structures. The optimal number of animals that can be kept efficiently in a single production unit are now well established. The number of animals kept in one unit, their stocking density and the area of land on which the manure can be disposed may well be controlled on environmental and welfare grounds. For grazing livestock, the ecological and environmental consequences may be a major factor in the optimal size of unit, with economic factors overridden by subsidies.

Many indices may be used to measure the efficiency of livestock units; biological efficiency, costs of capital, feed or labour, disease incidence, transportation costs for feed and manure, or net farm income. These indices show significant relationships with production unit size. The main weakness in large livestock units is a lack of balance between the technology used and the skills of the farm workers and managers. The overriding effects of biological efficiency on economic efficiency mean that productivity levels will continue to increase.

There is a need for more efficient advisory and management tools to improve the produc­tivity of large livestock units. Better training of livestock farmers in the use of these systems will also be necessary. The challenge for the next decade is to implement more widely existing technologies, whilst taking greater account of the environmental and welfare aspects of animal production systems. Key words: Livestock, unit, size, efficiency, factors, welfare, environment, pollution, advice.

Résumé

La tendance vers une proportion plus grande des unités d'élevage d'une taille élevée continu­era, mais elle reposera sur les structures des fermes du pays. Le nombre optimum des animaux qu'on peut élever avec efficience dans une unité simple de production est maintenant bien connu. Le nombre des animaux élevés dans une unité, leur chargement et la superficie de terre sur laquelle on peut disposer le fumier pourraient être contrôlés pour des raisons d'environ­nement et de bien-être. Pour les bestiaux pendant l'engraissement, les conséquences écologi­ques et sur l'environnement pourraient être les facteurs majeurs qui influent sur la grandeur optimum d'une unité, les subventions l'emportant sur les facteurs économiques.

On peut utiliser beaucoup d'indices pour mesurer l'efficacité des unités d'élevage: l'effi­cacité biologique, le coût du capital, les aliments ou la main d'oeuvre, l'incidence de la maladie, les coûts de transport, des aliments et du fumier ou le revenu net de la ferme. H y a des cor-relations importantes entre les indices et la grandeur de l'unité de production. Le défaut prin­cipal des grandes unités d'elévage est un manque d'équilibre entre la technologie utilisée et l'expertise des ouvriers et des directeurs. L'effet dominant de l'efficacité biologique sur l'effi­cacité économique aboutira à une augmentation continuelle du niveau de productivité.

Il y a un besoin de service de consultation et gestion plus efficients pour améliorer la productivité des grandes unités d'élevage. Une meilleure éducation des éleveurs dans l'utili­sation de ces systèmes sera aussi nécessaire. La demande pour la décade prochaine est d'utiliser

91

Table 1. Numbers of Cattle in the EEC, 1981-1987 (millions). Source: MLC European Handbook, 1988.

Country

Belgium Denmark West Germany Greece France Ireland Italy Luxembourg Netherlands United Kingdom Spain Totals, (EEC 10)

1981

2.9 2.9

15.0 0.8

22.5 5.6 8.9 0.2 5.0

13.1 » j

76.9

Numbers of cattle

1983

3.1 2.9

15.7 0.8

24.3 6.9 9.1 0.2 5.3

13.3 S Ï

81.6

1985

3.1 2.6

16.0 0.8

23.7 6.9 9.2 0.2 5.2

12.9 5.0

80.6

1987

3.1 2.3

15.4 0.8

22.3 6.6 8.9 0.2 4.9

12.2 5.0

76.7

% change

81/87

+ 7 - 2 1 + 1

0 - 1 + 18

0 0

- 2 - 7

î>

-0.3

davantage les technologies existantes, tout en tenant compte de l'environnement et du bien-être des animaux dans les systèmes d'élevage. Mots-clés: animaux, unités d'élevage, taille d'élevage, efficacité, facteurs de variation, envi­ronnement, polluton, bien-être des animaux, services.

Introduction

During the preceding decade, a number of technical and economic developments have resulted in marked trends in the size and organisation of animal production units. The cost of farm labour as a proportion of total enterprise costs has resulted in the mechanisation of both the feeding and manure disposal systems. However, mechanisation is only profitable for larger livestock unit sizes, depending on the species and feeding system. Large livestock units also require good records of animal performance and disease to be kept and reviewed regularly. The development of computer services, either as bureau to which paper records can be posted for processing, or more recently, on-farm computer systems, has also made it easier to manage large livestock units efficiently. The upper size limits for large livestock units are now fairly well established, so that it is possible to extrapolate past trends in some European countries and extend these to others where livestock units are still small. Using mainly EEC data, the present livestock situation will be reviewed, past trends identified, and conclusions as to likely future developments drawn.

Livestock population trends

Cattle

The total cattle population in the EEC appears to have peaked in 1983 at 81.6 million, and has subsequently declined to 76.7 million in 1987, a reduction of 6%. Most countries show only minor changes, but exceptions are Denmark, do wn by 21 %, and Ireland, up by 18% since 1981 (Table 1). The main cause of this reduction in cattle population is undoubtedly the introduction

92

Table 2. Numbers of dairy cows in the EEC, 1981-1987 (millions). Source: EEC Dairy Facts & Figures, 1989, Table 14.

Country

Belgium Denmark West Germany Greece France Ireland Italy Luxembourg Netherlands United Kingdom Spain Totals, (EEC 10)

1981

0.97 1.02 5.44 0.24 7.05 1.46 3.02 0.07 2.41 3.29 1.85

24.96

Numbers of dairy cows

1983 1985

0.98 0.95 0.99 0.91 5.74 5.45 0.24 0.22 7.20 6.51 1.54 1.53 3.22 3.08 0.07 0.07 2.52 2.33 3.43 3.26 1.88 1.88

25.92 24.30

1987

0.92 0.81 5.08 0.23 5.84 1.44 3.02 0.06 2.04 3.05 1.78

22.50

% change

81/87

- 5 - 2 1 - 7 - 4 - 17 - 1

0 - 6 - 1 5 - 7 - 4 - 1 0

Table 3. Numbers of pigs in the EEC, 1981-1987 (millions). Source: CEC 198ß Report, Table 3.5.3.9.

Country

Belgium Denmark West Germany Greece France Ireland Italy Luxembourg Netherlands United Kingdom Totals, (EEC 10)

of milk quotas in the EEC in 1984. The figures for dairy cow populations shown in Table 2 show a reduction of 3.4 million cows, 13% of the total, since 1983, with Denmark, France, and the Netherlands showing the biggest reductions.

Pigs

The total pig population in the EEC has shown a steady increase amounting to 8% since 1981, and is now 85.1 million. The biggest increase has been in the Netherlands, +39%, with Belgium and Germany showing increases of 9% each. Denmark has reduced its pig population by 6% over the same period. Full data are in Table 3.

93

1981

5.1 9.8

22.5 1.3

11.4 1.0 9.0

0.01 10.3 7.9

78.5

Numbers of pigs

1985

5.4 9.1

23.6 1.1

11.0 1.0 9.2

0.01 12.4 7.9

80.6

1987

5.9 9.2

24.5 1.2

11.7 1.0 9.4

0.01 14.3 7.9

85.1

% Change

81/87

+ 9 - 6 + 9 - 8 + 3

0 + 4

0 + 39

0 + 8

Table 4. Numbers of sheep in the EEC, 1980-1987 (millions). Source: CEC 1988 Report, Table 4.17.0.1.

Country

Belgium Denmark West Germany Greece France Ireland Italy Luxembourg Netherlands United Kingdom Portugal Spain Totals, (EEC 10)

1980

0.08 0.05 1.15 8.04

11.91 2.36 9.11

<0.01 0.90

21.61 " )>

55.22

Numbers of sheep

1986

0.12 0.05 1.30 9.99

10.79 2.77

11.29 <0.01

0.99 24.54 3.00

16.93 61.85

1987

0.13 0.07 1.38

11.03 10.58 2.92

11.45 <0.01

1.12 25.98 3.00

17.88 64.66

% Change

80/87

+ 63 + 40 + 20 + 37 - 11 + 24 + 26

0 + 11 + 20

0 + 6 + 17

Table 5. Numbers of goats in the EEC, 1980-1987( millions). Source: CEC 1988 Report, Table 4.17.0.1.

Country

Belgium Denmark West Germany Greece France Ireland Italy Luxembourg Netherlands United Kingdom Totals, (EEC 10)

1980

<0.01 0

0.04 4.53 1.13

0.98 "

0.01 0.01 6.71

Numbers of goats

1986

<0.01 0

0.05 5.70 1.01

1.17 0.01 0.04 0.05 8.01

1987

<0.01 0

0.05 6.60 0.98

1.20 <0.01

0.04 0.05 8.93

% Change

80/87

+ 3 0

+ 2 + 46 - 1 3

+ 22 0

+ 258 + 269

+ 33

Sheep

Sheep populations in EEC countries vary from 26 million in the UK to negligible numbers in Belgium and Denmark. France, Greece and Italy have 10-11 million sheep each (Table 4). The total sheep population in the EEC has increased by 17% since 1980, from 55.2 million to 64.7 million in 1987. The major increases have taken place in Greece, +3 million, Italy, +2.3 million and the UK, +4.4 million. The EEC sheepmeat regime significantly altered the economics of sheepmeat production, and these increases are almost certainly a reaction to this improved profitability. Whilst sheep are suited to hill and mountain areas, sheep have returned in large numbers to lowland areas in the UK.

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Table 6. Poultry populations in the EEC, 1980-1986 (millions). Source: CEC 1988 Report, Table 4.17.0.1.

Country

Belgium/Luxmbourg Denmark West Germany Greece France Ireland Italy Netherlands United Kingdom Totals, (EEC 10)

Numbers of poultry

laying hens broiler chickens

1980 1986 1980 1986

12.56 10.72 71.28 85.82 4.56 4.22 70.59 82.89

55.80 49.70 253.96 212.22 16.76 16.78 " 67.69 72.55 68.60 525.57 622.33 2.80 3.28 25.77 32.19

47.50 48.04 392.79 330.04 34.55 39.29 298.89 297.34 57.33 52.04 404.67 529.60

304.52 292.77 2,043.50 2,260.13

Goats '

Goats only figure significantly as livestock in Greece, 6.6 million, Spain, 2.8 million, and France, Italy and Portugal at around the 1 million level. The total goat population in the EEC 10 has increased by 33%, from 6.7 million in 1980 to 8.9 million in 1987 (Table 5).

Poultry

The number of laying hens in the EEC has declined by 4% from 304 million in 1980 to 293 million in 1986, (the latest date for which complete data are available; Table 6). Trends appear similar for all of the EEC 10 countries. Table chicken, (broiler) hatchings were recorded as 2,260 million for the EEC 10 in 1986, an increase of about 7% over 1980, but incomplete data make identification of country trends difficult. Most changes are ±3% per annum since 1980.

Trends in livestock unit size

Dairy cattle, pig and poultry units are those which have lent themselves to mechanisation and the development of large units on one site, but even so, the trends and present situation in various of the EEC countries varies quite widely, depending on the level of technical support and infrastructure present. There are two ways of presenting animal unit size distributions, both to be found in the standard EEC Tables, (CEC, 1988). The number of units of a particular size range can be quoted, or alternatively, the proportion of the total livestock population kept in units of the size range under study. The latter has been chosen here because it demonstrates more clearly the relevance of the small units to a countries total animal production output. As an example, Greece has 81% of its pig units with less than 9 pigs, but 46.5% of all pigs in Greece are kept in units of more than 1,000 pigs, run by only 0.5% of all pig farmers.

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Table 7. Dairy herd size distribution EEC 1987. Source: CEC Report 1988, Table 3.5.3.6.

Country

Belgium Denmark West Germany Greece France Ireland Italy Luxembourg Netherlands United Kingdom Means

<10

4.0 2.5

12.1 64.8 6.2 6.5

23.5 1.4 1.6 0.4 9.1

Percent of animals in herd size of

10-49

70.2 59.3 75.0 29.3 78.4 60.0 49.0 69.9 42.7 19.1 59.7

50-99

23.0 31.8 12.0 5.0

14.2 26.0 16.4 27.3 45.2 38.3 21.8

>100

2.8 6.3 0.8 0.9 1.1 7.6

11.1 1.4

10.6 42.2 9.4

Table 8. Pig herd size distribution in the EEC, 1987. Source: CEC Report, 1988, Table 3.5.3.9.

Belgium Denmark West Germany Greece France Ireland Italy Luxembourg Netherlands United Kingdom Means

<10

0.4 0.2 2.8 4.7 0.9 0.7

10.4 3.5 0.0 0.2 2.2

Percent of animals

10-49

2.5 2.8

10.3 9.7 3.0 2.8 6.0

11.0 0.7 1.6 5.0

50-199

13.4 13.7 27.2 14.8 10.3 3.4 5.1

28.4 9.1 4.9

14.4

in herd

200-399

17.3 16.9 22.7 6.9

16.6 3.7 6.6

19.7 13.7 7.4

15.7

size of

400-999

34.0 36.5 31.5 17.4 38.3 11.4 18.0 25.1 34.9 19.3 30.7

> 1,000

32.5 29.9 5.6

46.5 31.0 77.9 53.8 12.3 41.5 66.5 32.0

Dairy herd size

The 1987 dairy herd size distribution for the EEC 10, as a percent of the total number of cows is given in Table 7, showing that the majority of cows are kept in herds of 10-49 animals in Belgium, Denmark, Germany, France, Ireland, Italy and Luxembourg. The UK stands out with 42% of its dairy cows kept in herds greater than 100 cows. Only about 2.5% of the total number of UK dairy units are larger than 200 cows, suggesting that this an optimum size for UK conditions. The UK is without legal restrictions on farm amalgamations, unlike some other EEC countries. Several countries, (Greece, Italy, and Germany), have large numbers of small dairy farms with less than 10 cows, but as a proportion of the industry these are not very significant, and can be expected to reduce further in numbers, unless part time farming is a strong element in the economic structure.

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Pig herd size

The 1987 pig herd size distribution for the EEC 10, as a percent of the total number of pigs is given in Table 8, showing that over 50% of pigs are kept in herds of greater than 400 animals in many EEC countries. Ireland with 77.9% of pigs kept in herds of greater than 1,000 stands out, closely followed by the UK at 66.5%, Italy at 53.8% and Greece at 46.5%. Other data from Table 3.5.9.11 of CEC Report 1988, show that the trend over the period 1981 to 1987 was for the number of pigs kept in herds of more than 400 pigs to increase, with the greatest increases in numbers of pigs taking place in herds of greater than 1,000. The small pig farmers, keeping less than 10 pigs, were a large proportion, 63.6% of the total number of pig farmers in the EEC 10 in 1987, but they only keep 2.2% of the pig population!

Sheep flock size

There appear to be no data on sheep flock size in the CEC statistics, but UK data, (covering 40% of the EEC sheep population), show clear evidence of an increase in average flock size since the introduction of the EEC Sheepmeat regime. In 1977 in England, average flock size was 227, but Wales averaged 429 sheep/flock. By 1987, England had increased to 303 sheep/ flock, and Wales to 567 sheep/flock, increases of 33.5% and 32.2% respectively over the 10 year period. In 1987,47.3% of sheep in England & Wales were kept in flocks of greater than 1,000, with 19.4% of these in flocks of over 2,000. Mechanisation is not a significant factor in sheep husbandry, but labour costs and the scarcity of trained shepherds are. A particular fea­ture of development in the UK, has been that of winter housing and lambing buildings, with effects on feeding systems and working conditions for shepherds. Most sheep still spend the major part of the year as grazing animals, however.

Elsewhere in Europe, sheep are kept as milking animals, so that the mechanisation aspects of both feeding and milking are probably dominant in determining unit sizes. Similar trends affecting goat herds are also probable, but the writer has not found suitable data to quote.

Livestock population densities

In the case of grazing livestock, such as cattle, sheep and goats, the relationship to land area is determined primarily by the forage supply, resulting from factors such as the fertility of the soil, climate, and level of nitrogen fertilisation used. However, the proportion of concentrates bought on to the farm can influence this relationship quite strongly, within certain nutritional limits. Manure disposal has not, until recently, been the primary constraint on the number of ruminant animals kept on a given area of land. The current increased awareness of nitrate pollution of water supplies, either as groundwater or in streams and rivers, has resulted in an awareness that sustainable upper limits to livestock population densities and fertiliser usage have already been passed in some areas. The amount of the animal manure applied per hectare is a considerable factor in this problem.

In the case of intensively housed pigs and poultry, all feed is normally imported onto the farm, except where the units are located on cereal growing farms, and use is made of home grown cereals. The EEC Cereals regime, with its high prices for cereals, has often mitigated against such obviously sensible practices. Manure disposal from pig and poultry units should be sensibly related to land areas available for the purpose, but unsuccessful attempts have been made to dry or ensile poultry manure, making use of the end product as a low grade nitrogen source for ruminants. The use of pig manure as a source of methane, still results in large amounts of solid waste to be disposed of. Thus attempts to dispose of pig and poultry manure by methods other than on to land, have largely been a failure.

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Table 9. Cattle & Pig densities in the EEC, 1987. Sources: CEC 1988 Report, Tables 35.2.1 & 3.5.3.9.; EEC Dairy Facts & Figures, 1989, Table 14.

Country

Belgium Denmark West Germany Greece France Ireland Italy Luxembourg Netherlands United Kingdom Totals/means (EEC 10)

UAA (mha)

1.41 2.82

11.96 5.74

31.35 5.68

17.40 0.13 2.03

18.51 97.01

Cows (xlO6)

0.92 0.81 5.39 0.24 5.84 1.44 3.02 0.06 2.17 3.05

22.95

Cows/ha

0.65 0.29 0.45 0.04 0.19 0.25 0.17 0.46 1.07 0.17 0.24

Pigs (xl06)

5.86 9.23

24.47 1.17

11.70 0.96 9.38 0.08

14.35 7.92

85.15

Pigs/ha

4.17 3.28 2.65 0.20 0.37 0.17 0.54 0.61 7.06 0.54 0.88

Dairy cow stocking densities

Standard CEC data on livestock populations and the Utilised Agricultural Area, (UAA), for each EEC country have been used to calculate overall stocking densities for cows in Table 9, to demonstrate the variability that presently obtains. The data for cows per hectare of UAA for the Netherlands at 1.07 are nearly double those of Belgium, Germany and Luxembourg, 0.65,0.45 and 0.46 cows/ha UAA respectively. France, Italy and UK are at below 0.2 cows/ha UAA. When the area of land actually utilised by the dairy herd is taken into account, a rather different picture emerges. As an example, the UK national dairy herd averages 2.19 Livestock Units (LSU) per ha (MMB, 1989), and similar figures are quoted for Germany, Ireland and Brittany, (MMB, 1983). Dairy herds in Holland and Denmark, however, in 1983 averaged 2.87 and 3.24 LSU/ha (MMB, 1983).

Pig population densities

Similar data for pig populations in the EEC 10 are also given in Table 9. Again, the Netherlands tops the league with 7.06 pigs/ha UAA, nearly double that to be found in Belgium, 4.17, and Denmark at 3.28 pigs/ha UAA. Obviously these data are only broad averages, and conceal real problems where livestock populations are divorced from the areas of cereal growing, as in the Netherlands, Belgium and parts of the UK. Thus, for example, North Brabant in the Netherlands averages 21 pigs/ha, three times the national average, West Flanders in Belgium averages 16 pigs/ha, and Lombardy in Italy averages 2.4 pigs/ha, nearly five time the national average. Given the problems now being experienced in the Netherlands, in trying to establish a balance between manure output from livestock units and the*area of land available for its disposal, it seems reasonable to conclude that these high stocking densities are not sustainable in the longer term, without considerable state interference in the logistics and economics of manure disposal.

It is significant that the Netherlands tops the list for both cows and pigs, emphasising the importance of imported animal feeds and low transport costs in supporting such high animal population densities. The port of Rotterdam has been the main point of entry of large quantities of raw materials for animal feeds, such as manioc, maize gluten feed, soya bean meal etc, so that close proximity to Rotterdam has been a considerable economic advantage to Dutch and

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Belgium livestock farmers. Similar arguments apply with equal force to the density of poultry units per hectare of UAA, but are omitted here for space considerations. The steady expansion of broiler flocks already referred to suggests that limits may have to be imposed on further expansion of broiler units.

This review of the diversity of animal production enterprises has shown several important features: a. The wide range in the proportion of animals kept in large production units in various EEC

member states. b. The trend to larger livestock units has progressed at different speeds in different countries,

but there seem to be no reasons why the majority should not proceed to a higher proportion of large units, unless legislation against farm amalgamations prevent then so doing, or for sound environmental or economic reasons.

c. From the problems being experienced, the re-establishment of a firm link between animal production units and related areas of land for manure disposal would appear vital, this is an argument for mixed farms against specialised livestock farms.

d. The upper size limits for livestock units for different species are now well established, with different factors proving limiting. Labour availability, suitability for mechanisation, and the logistics and economics of manure disposal appear to dominate.

e. The small (and part-time?) livestock farmer may still appear numerically important, but their output of animal products is in most cases insignificant. The improved standards of animal health and welfare now being required may well ensure their further reduction in numbers. /

Economies of scale

The development of costly but efficient new technologies are the main reason for the recorded increases in average herd and flock size. The labour, feed, machinery and building costs per unit of milk and meat are changed by herd or flock size, but the effects will differ depending on the level of technology utilised. Figure 1 gives a schematic presentation of these effects, (Neimann-S0rensen & 0stergaard, 1983)

Total cost per unit of production High technology

Low technology

Herd s i ze

Figure 1. Cost curves for different levels of mechanisation and herd size.

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Weaknesses in existing systems

Most livestock farms have weaknesses in the system of production being used. The reasons can be summarised as being due to a mismatch between the technology being used and the skills of the farm workers and the manager in charge. The collapse of large livestock enterprises is often due to such failures. As an example, failure to observe and record cows coming on heat and due for service, can lead to a high proportion of the herd being dry, leading either to high replacement costs or high feed costs without income from milk. A schematic repre­sentation of this effect is shown in Figure 2.

Low technology production systems are much more robust, and can be profitable with relatively unskilled workers. However, increasing worker skill will not result in improved eco­nomic performance in such units. With high technology units, high levels of managerial and worker skill are essential for high economic performance levels.

Indices of efficiency of animal production units

Numerous indices of efficiency are in use for the assessment of animal production unit efficiency, with a wide range of units of measurement being used. Space will not permit an extensive review of all these biological and economic indices, but they can be grouped together by their type across livestock species, as follows: a. Biological efficiency (Figure 3) b. Disease incidence (Figure 4) c. Investment/fixed costs per kg product (Figure 5) d. Management & labour costs per kg product (Figure 6) e. Transportation of feeds and manures (Figure 7) f. Net income per man hour for different conditions (Figure 8) These indices also show general relationships with herd/flock size, which are demonstrated in Figures 3 to 8.

Level of worker & manager skill

Minimum level required for economic balance

low medium high level of technology

Figure 2. Relationship between level of technology available and worker skill required for economic balance between input and output (Neimann-S0rensen & 0stergaard, 1983).

100

kg milk/cow

Herd s i z e

% i ncidence

Herd s i z e

Figure 3. Biological efficiency. Figure 4. Disease incidence.

Investment/animal or kg product

Herd size

Manhours/animal

Labour

Management_. — — '—

Herd size

Figure 5. Buildings & equipment. Figure 6. Management & labour.

Tonnes or kilometres /animal or product

Herd size

Net income/manhour

Herd s i z e

Figure 7. Transportation of feeds and man- Figure 8. Net income for different condi-ures. tions.

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Table 10. Productivity of Pig herds, 1987. Source: Martin, MA., 1988.

Pigs per sow per year Breeding herds Integrated herds

Litters per sow per year Breeding herds Integrated herds

20-50

19.6 18.7

2.15 2.09

50-100

19.9 19.0

2.19 2.18

Herd size

100-200

20.8 20.8

2.25 2.26

200-500

21.3 20.8

2.32 2.29

>500

21.7 22.1

2.36 2.41

Biological efficiency

Many measures of biological efficiency are used, one of the simplest being level of production of milk, meat, eggs etc per animal over a given time period. As production level rises, the maintenance requirement of the animal becomes a smaller proportion of the total feed requi­rement, so that feed conversion efficiency is improved. Reproductive rate is important for sheep, pigs and goats, whilst calving interval is important for cattle. Reproductive efficiency data for pig herds of various size (Table 10) shows improved levels with increase in sow herd size, contrary to most expectations. Whilst variations in feed costs and market returns can produce short term effects, experience is that higher biological efficiency will prevail.

Disease incidence

Large livestock units present considerable disease hazards, because of the ease of transmission of infections through the flock or herd. Large amounts of infective material can also be built up, resulting in the spread of disease to other units, causing an epidemic. Special monitoring programmes or preventative medicine approaches are required, rather than the 'fire brigade' method of disease control. Pig and poultry units have to routinely use considerable quantities of medicated feed in order to maintain high levels of production. Failures of management to monitor and act in good time can prove disastrous to the performance of these large units. The alternative approach is the establishment of minimal disease herds or flocks, with restricted access to them. Disease control costs figure quite largely in the total costs of many large livestock units. Given suitable control measures, disease levels may be lower in large units than in small ones.

Investment in machines and buildings

Control of fixed costs incurred by the erection of buildings, purchase of machinery etc is crucial to the success of most farming operations. Over equipping with machinery is a common fault, particularly with small and part-time farmers. When the money is borrowed and high interest charges incurred, it can cause the financial failure of the whole enterprise, despite efficient operation of the unit itself. The only way to reduce fixed cost charges per unit of product is to increase productivity still further. Animal welfare considerations are likely to increase building costs per animal in the next decade.

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Management and labour

The main labour requirements for livestock units are to prepare and feed the animals, remove the manure to storage or to the fields, and remove the animal product such as milk or eggs. The mechanisation of the feeding of large dairy and beef herds enable one man to feed several hundred cattle in the space of a few hours. Housed sheep are now being fed similarly. Pigs and poultry are commonly entirely fed automatically. Automatic manure removal from the building to a manure store is also commonplace. Thus the labour requirement is continually being reduced, but at a considerable investment cost in buildings and machinery.

Transportation of feeds and manures

Ruminant animals require large tonnages of forage to be stored for the 6 winter months of the year. This has to be transported from the fields in which the crop was grown to a central store. Similarly, the solid portion of the manure has to be tranported back to the land, and the liquid portion has either to be pumped and sprayed on to the land, or treated for disposal into water courses. As herd size increases, the distances involved become greater and costs increase disproportionately.

Net income

Conventional methods of costing and budgeting farm enterprises, such as Gross Margins, Margins over feed and fertiliser, ignore the effects of Fixed Costs, because it is difficult to allo­cate fixed costs accurately to each enterprise. When the fixed costs also include large bor­rowings to finance buildings or machinery, then the assessment of the net income being generated by the farm becomes crucially important.

Advisory and Management Tools needed for the future

The range of livestock unit sizes currently present in Europe present a formidable challenge to the livestock supply industry and to official advisory services. Clearly, training, advice and support which is appropriate to a farmer with 10 cows is unlikely to suit one with 200 cows. There may be a need to develop special programmes for part-time small livestock farmers in many respects. Whilst they can take advantage of the feed formulations and disease control measures marketed by the supply industry, they may find advisory and veterinary costs proportionally much larger in their small units. Feed costs will also be higher, because of the need for small deliveries in bags instead of in bulk. The development of computerised bureau services, either by post or electronic mail, is one way of reducing the costs of visits to small farms, whilst upgrading the quality of advice received at the same time.

For the increasing number of large livestock units, the main need is for managers who are highly trained and numerate, able to scrutinise computer records relating to the unit under his care, spot deviations from the normal and take quick and appropriate action. The records must relate to the financial performance of the unit as much as its physical performance. The keeping of accurate records of the health and productivity of the stock is vital to these large enterprises, and this requires the whole hearted and consistent efforts of the stockmen actually working with the animals, eg in observing animals on heat and due for service. They need to be backed up suitable computer software designed for the purpose, and advisers who are expert in the use and interpretation of records produced by the software.

Feed costs are a large part of the costs of any animal production unit, so that monitoring of feed composition and consumption should be a regular routine, particularly where home grown forages and crops are to be utilised. The development of Near Infra Red Reflectance methods

103

of feed analysis have increased the speed, reduced the costs, and improved the precision of feed analysis. These can be combined with computer models which handle the interaction between the animal, its environment and its nutrient requirements for the desired level of production.

There are now instruments capable of measuring the amount of fat in live beef catde and pigs, to assist the unit manager in judging when to send animals to particular markets. Another machine scans ewes for twin lambs, so that their dietary regime can be appropriately adjusted. Such assessments are normally carried out by contractors visiting the unit when required. Further developments in this field can be anticipated.

Conclusions

Because of the wide range of livestock units to be found in various European countries, many of the problems they present have already been solved. The challenge of the next decade is to implement more widely the technologies already developed, and to train both managers and stockmen to higher levels of appropriate skills. Computers both on and off the farm will play an increasing role in both managing and monitoring the performance of large livestock units. The main research challenges are in the environmental pollution, and in the animal behavi­our/welfare field. Special advisory programmes may need to be developed, if the small, part-time farmer is to remain an important part of livestock production scene in Europe, for environmental or other reasons.

Acknowledgements

The author was greatly assisted by a number of colleagues, each an expert in a particular field, and their contributions to this paper are gratefully acknowledged. In alphabetical order they were A.H. Andrews, N. Benedictus, F. de Boer, J.F. O'Grady, V. 0stergaard, T. Treacher and A.J. van der Zijpp.

References

CEC, 1988. The Agricultural Situation in the Community, 1988 Report. Commission of the European Communities, ECSC-EEC-EAEC Brussels Luxembourg 1989.

EEC Dairy Facts and Figures, 1989. Milk Marketing Board, Thames Ditton. Martin, MA., 1988. Moorepark Pig Seminar, 1988. MLC European Handbook, 1988. Meat & Livestock Commission, Milton Keynes. MMB, 1983. A Comparison of European Dairying. Farm Management Services Report No.37,

Amies, S J., Milk Marketing Board, Reading. MMB, 1989. Milkminder Annual Report 1988-9. FMS Information Unit Report No.66, Poole,

A.H. & Stock, S.R., Milk Marketing Board, Reading. Neimann-S0rensen, A. & 0stergaard, V., 1983. Systems for efficient livestock production.

Proc. Vth World Conference on Anim. Prod. Tokyo. 8 pp.

104

Management of consumption, demand, supply and exchanges

D. Matassino*, G. Zucchi** & D. di Berardino*

* Dipartimento di Scienza dellaproduzione animale, Université degli Studi di Napoli 'Federico II', 80055 Portici - Napoli, Italie

** Istituto di Zooeconomia, Facoltä di Agraria, Université degli Studi di Bologna, 42100 Reggio Emilia, Italie

Summary

At beginning of the 3rd millennium, the perspectives of the management of consumption, demand, supply and exchanges of products of animal origin present themselves in a highly diversified way, in relation to the main geo-economical regions of the world. The diversifica­tion depends on the process of socio-economic development, the available resources and the possible technical productivity peculiarities of each region. However, an internationalization and globalization process should be expected.

Five phases, linked to the level of income, characterize the consumption of animal products: the first three are of 'quantitative' nature, the other two 'qualitative', depending on the relevant intrinsic and extrinsic characteristics. Eight sceneries referring to economically similar areas, can be traced: North America-Western Europe, Japan, Australasia, Eastern Europe, Middle Asia, Latin America, Africa and the oil rich Middle East.

By the year '2010', the human population will be increased by nearly two billion and a further remarkable demographic development is foreseen by the year '2050', for which the actual production of proteins of animal origin must be doubled in order to satisfy the nutritional needs of the world population.

The management of some productive parameters is 'conditio sine qua non' to answer to the challenge of the beginning of the 3rd millennium, particularly with respect to water, soil and animal and plant genetic variability. Preservation of the environment will be of major importance. The concept of 'resource', in the industrialized world, will be modified. It is possible that the indigenous animal genetic types must increase in order to meet the demand and the new needs of the growing human population. The actual phase of development is characterized by major, deep and fast changes which enhance the rapid progress in the innovations of the productive processes and of the products as well.

The innovative biotechniques (IB) have to be considered as the necessary condition, especially on a long term scale, for any process of general and specific economical develop­ment. They will allow a reduction of costs and an increase in efficiency of the production factors and will characterize the fifth industrial revolution (new Kondratieff cycle): this cycle will lead toward very high grades of differentiation in the production of goods, with a tendency toward the prevalence of the specialized economies. The employment of IB will have strong repercussions on the agro-nutritional system. The future 'foods' could be very different from those we know today, for several reasons (dietetic properties, transformation processes, techniques of conservation and distribution, etc.).

The consumer, strongly influenced by the instruments of 'hidden' persuasion, will be more careful and will prefer natural 'healthy' food. The demographic trends and a different 'style' of life will change man's nutritional habits. The 'safety' of food will be another important indicator in the near future. Technical innovation of food production of animal origin will have to be approached under a different philosophy, namely 'the total quality of the product'. Key-words: animal products exchanges, consumption, biotechnology, foods, demography.

105

Résumé

Au début du troisième millénaire, il faut faire des différences dans les grandes régions géo-économiques du monde en ce qui concerne les perspectives dans le domaine de la demande, de l'offre et des échanges de produits d'origine animale. Ces différences dépendent du divers degré de développement socio-économique, de l'allocation des ressources disponi­bles et des techniques de production potentielles dans chaque région. On peut cependant prévoir un processus d'internationalisation et de globalisation. Cinq phases, dépendant du revenu, caractérisent la consommation des produits animaux: les trois premières sont de nature 'quantitative' et les deux autres de nature qualitative' en raison des caractéristiques intrinsèques et estrinsèques (services incorporés). Huit scénarios, relatifs à des zones économiquement similaires, peuvent être tracés: Amérique du Nord-Europe de l'Ouest, Japon, Australasie, Europe de l'Est, Asie centrale, Afrique, Amérique Latine, Moyen-Orient riche en pétrole, etc.

En l'année 2000, la population mondiale comptera un milliard de personnes en plus, et on prévoit pour l'année 2050 un ultérieur et considérable développement démographique. La production alimentaire devra donc être doublée pour pouvoir satisfaire la demande de la population mondiale. Les produits animaux de même que les produits végétaux doivent rendre à la terre au moins la même quantité d'énergie consommée pour leur production. On doit tendre à une amélioration du régime alimentaire. L'exploitation de quelques facteurs de production est une 'conditio sine qua non' pour répondre au défi à l'orée du 3ème millénaire, surtout en ce qui concerne l'eau, la terre et la variabilité génétique des animaux et des végétaux.

Il faut donner une importance particulière à la protection de l'environnement. Le concept de 'ressources ' sera modifié dans le monde industrialisé. Il est possible que les types génétiques animaux doivent augmenter pour faire face à la demande et aux nouveaux besoins de la population humaine en accroissement. L'emploi de régimes capables de satisfaire complète­ment les exigences nutritionnelles de l'homme seront toujours davantage le patrimoine des générations futures.

Cette époque historique est caractérisée par des changements importants et soudains qui augmentent les espoirs et les angoisses de l'humanité. Le progrès rapide dans les nouvelles techniques de la production et dans les produits ainsi que le passage d'une conception plutôt statique de la vie à une conception très dynamique ont des aspects tres attrayants mais posent certainement des problèmes.

Les nouvelles biotechnologies (NB) doivent être considérées comme une condition néces­saire, surtout à long terme, en ce qui concerne tous les processus de développement économi­que du point de vue général et spécifique. Les innovations biotechnologiques pourront réduire les coûts et augmenter l'efficacité des facteurs de production. 11 est probable que la cinquième révolution industrielle sera caractérisée par l'emploi des NB. Ce nouveau 'cycle Kondratieff ' portera à une plus grande différenciation dans la production de biens qui sont nécessaires à satisfaire des exigences changeantes, avec une tendance à la prépondérance des économies de spécialisation. L'emploi des NB aura une répercussion considérable sur le système agro-ali­mentaire. Les aliments qui seront consommés dans l'avenir seront différents de ceux existant actuellement pour différentes raisons: caractéristiques diététiques, procédés de transformation des matières premières, techniques de conservation et de distribjution, etc.

Le consommateur, malgré l'influence de la persuasion 'occulte', tendra à une alimentation plus naturelle et préférera des aliments plus sains. Les habitudes alimentaires sont en train de changer rapidement par suite des tendances démographiques et des différents styles de vie. La valeur intrinsèque d'un aliment sera un indicateur important pour le proche avenir. Les innovations techniques en ce qui concerne la production d'aliments d'origine animale devront être réalisées avec une autre philosophie, c.à.d. en tenant compte de la 'qualité totale du produit'. Mots-clés: échanges de produits animaux, consommation, aliments, démographie, biotechno­logie.

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Introduction

The topic which has to be examined in this particular context is wide, complex and cannot be fully covered in a few typewritten pages. Therefore, the paper will discuss the problems related to the topic itself with a rather philosophical and futuristic approach instead of tracing specific schemes of intervention. Such complexity comes from the manifold exploitation of the biological phenomena as well as of the socio-economic and cultural ones. At the beginning of the 3rd millennium, the management of production, demand, supply and exchanges of products of animal origin is a variable of the international economic system; such a system is characterized by a strong interdependence among the national economies which tend to group in subsystems involving various geographical areas (for instance, EEC, COMECON). It is predictable that such an interdependence will tend to intensify, especially under the influence of: (a) scientific and technical progress, (b) the use of information and (c) environmental monitoring.

The history of the last 20-30 years suggests that the industrialization process has provided a remarkable increase in uniformity and inter-changeability. Simultaneously, in the countries with advanced economies a marked tendency is going on toward a more differentiated society, under social, political and economic profiles, due to the remarkable variability in the informa­tion received by the single individual.

As in the biological systems, life and the functioning of social, political and institutional systems are the results of the way in which the information is treated.

To foresee the future of a society which is highly composite and various in its structure and super structure is not simple, whatever its geographical level. The futures are many. By following a logical approach we can say that: (a) the desirable futures can be several, depending upon the sciencefiction and ethics, (b) the probable futures are characterized by a different likelihood of realization.

The decision process cannot be conditioned by econometrical models identifiable with the 'Pigmalion' complex. A model does not create new structures, while the predictable structural changes and their nature, when inserted in a model, may provide decisional indications. It would be mistaken, for any choice to be taken, to consider only what is measurable and expressable by a number, thinking to be unimportant what is unmeasurable, such as human 'weakness'. A typical example is any living being, especially of high organizational level ('mammal'). We are not absolutely 'fail - safe', being able to survive in case of errors. In the near future we hope that the 'frattal' geometry, theorized by Mandelbrat in 1975 could provide a significant contribution for a better understanding of some dynamic processes, not only in biology (i.e. passage from the healthy to the sick condition) but also in the socio-economical area. At the present time, for any decision process it's important to know whether a given fact is an important event or simply a trend.

We are in a highly dynamic historical period with deep crisis in several sectors. A possible solution of this problem can be seen in a management of the crisis under long term perspectives. In such management, business cannot neglect politics. The qualification of the managerial class is a dilemma known even to Plato.

The development of animal production in the EEC can only take place in agreement with that of other european (Oriental) and underdeveloped countries.

In order to overcome some of the actual barriers, a different view of the society is developing: passage from a multinational to a multicultural society. It's a very complex approach, but unavoidable under a perspective of 'globalization' in the solution of the problems.

According to the experts, in the next 20-30 years there will be an intensification of the 'mass' society of individualistic type. Such an apparent paradox means that every one wants to be considered a 'special' person, even though his individual treatment is not different from that practiced to other persons.

107

It will be necessary to establish a new policy of 'thinking' with special concern towards the problems related to the use of innovative techniques and their social implications in a society more and more projected toward a 'high culture' condition. Within such a policy, a remarkable role will be played by the general educational system and by an educational system specific for animal production.

The school must be able to shape strategical 'thinkers' and not only good technicians. If the necessary changes in the pedagogic and didactic systems do not take place, there will be the risk of having a managerial class which would tend to age, severely restricting the space reserved for youth because of the remarkable dynamism of the changes involving the external world of the enterprise.

Environment

Animal and plant production must return to the land what they take from it or even more. The respect of the environment will require an increasing and pre-eminent attention, even in spite of an increase in production to meet the needs of food of a population which not only increases in number but wishes to improve the diet from a qualitative viewpoint. In the industrialized world, the idea of 'resource' is identified with something to exploit, while it will be necessary to consider it as a good to protect, to keep and to use according to a planned conservation programme. Hence the need to increase, for instance, the number of genetic types used in order to meet the various and new needs of human population. Man is strongly becoming aware of the right to his own existence as well as the earth's existence, without renouncing the acquired benefits or the future benefits which will derive from the new scientific discoveries. All that also affects the choices of life styles diversified by culture and traditions. The agro-alimentary sector itself can be considered as a key example for the improvement and the protection of the environment. There is no doubt that the need for pollution reduction will be the stimulus for inventions and for searching out new solutions. The environmental policy should not be the art of the possible, but the art to make possible that which is necessary. We must learn a lot from nature in terms of environmental management. From this learning process should derive a real derogation from the protectionism of industrial pollution.

The use of new 'in toto' breeding management techniques could be interesting: for example from the genetic improvement to the rationalization of the diet and the modification (direct or indirect) of hormonal control. The improvement of the efficiency level or biological capacity of the animal in zootechnical production, 'ceteris paribus', would allow the same production (meat, milk, eggs, etc.) to be obtained using less food and, by consequence, there would be a reduction of the quantity of excreta and urine per unit of product. Therefore, by increasing the yield of the animal, it will be possible to reduce the possible polluting effects linked to zootechnical discharges. It can be estimated that the improvement of the productive 'perfor­mance' of animals realized in the last decade has contributed to reduce the polluting power by, approximately, 25% in swine breeding and 30% in poultry. In the next 10 years a further reduction of 30% can be foreseen. In fact, we must foresee a remarkable reduction of the land surface dedicated to the production of food for animals and a corresponding, if not higher, increase of land used as pastures. All that will imply an important revision of the management of the territory with an increase of extensive breeding and with parks for breeding animals having a particular biological value (Matassino, 1988a).

It is thought that the variation in some climatic variables (for example, the temperature), foreseen until 2050, will induce a great modification of all the life systems on our planet. The ecologists estimate that, in nature, there is a direct relationship between the extension of an 'habitat' and the number of species that can live in such a habitat. On this concept is based the 'theory of equilibrium of insular biogeography' (McArtur & Wilson, 1967) proposed initially to explain the variation in the number of species on the islands (Island) that actually is being

108

extended to other ecosystems. The future of the planet Earth will be the result of the modality by which man will mould and manage the present times.

Demographic development

The demographic development and the migratory movements represent two fundamental elements upon which we have to build our future. The overcoming of a series of constraints as well as the need to communicate with each other, regardless of the cultural diversities, will determine a remarkable change in the life-styles and also the construction of new equilibriums of peace. Such deep changes will affect the general and the specific policies of the various countries, as well as the interactions among the countries, at all levels. The policy of the agro-alimentary system will be highly conditioned by human demographic development and its variation in different areas, with particular reference to the demographic age of the population.

In the current year on the planet Earth there are nearly 5.292 billion inhabitants, of which 2.628 are women and 2.664 men. According to the projections shown in Figure 1 and Table 1, by considering an 'average' demographic increase rate, the human population should reach: 6.25 billion in the year 2000,7.191 in the 2010, 8.467 in the 2025 and 9.684 in the 2050.

Therefore, within 20 years there would be an increase of nearly 1.9 billion inhabitants (36 per cent). By considering a 'low' and a 'high' demographic increase rate, the total population of the planet Earth would be, respectively: 6.09 and 6.41 in the year 2000, 6.80 and 7.56 in the 2010,7.59 and 9.42 in the 2025,7.81 and 12.81 billions in the 2050. Two strong tendencies can be observed: the first regards the class of age 'birth-14 years' which from the actual 32 per cent decreases to 28.5 of the 2010 and to 11.3 of the 2050; the second regards the class of age '> 60 years' which, respectively, reaches 10.6 and 26.5. Such tendencies practically concern all of the geographical areas considered. These variations in the demographic structure

14.000

12.000

10.000

g 8.000 S

m 6.000

4.000

2.000

EARTHPLANET

- < 1 —

1980 1960 1980 2000 2020 2040 YEAR

Figure 1. Demographic projections of the human population.

2060

109

Table 1. Total human population (x 1,000,000) on the level of 'average' prediction in some geographical areas and its demographic structure for classes of age1. From 1990 to 2025 it is FAO forcast; from 2026 to 2050 it is our projection. Portugal has been added, to the Mediterranean Countries while Japan has been excluded from Asia;

Geographical area

Western Europe

Eastern Europe

Mediterranean Countries

Ussr

Japan

Asia

Africa

Latin America

North America

Oceany

Planet Earth

Year

1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050

Total

358 363 364 358 341 117 121 125 128 134 394 448 498 560 609 288 308 326 351 386 123 129 132 129 111

2,985 3,569 4,094 4,761 5,053

648 872

1,148 1,581 2,311

449 540 631 760 916 276 295 311 333 361 26 30 34 39 46

5,292 6,251 7,191 8,467 9,684

children

65 65 61 57 40 27 25 25 24 31

116 125 125 121 79 73 73 72 73 60 23 22 23 20 23

997 1,137 1,139 1,080

407 293 387 480 541 302 161 177 186 196 186 59 59 58 60 41 7 8 8 9 7

1,712 1,958 2,057 2,063 1,099

Number

youth adults

54 44 43 40 95 17 18 16 17 11 70 75 82 83 72 42 48 49 49 52 19 16 14 15 15

619 623 734 742 748 123 170 230 325 497 89

102 115 124 126 40 40 41 40 66 5 5 5 6 8

1,011 1,069 1,256 1,358 1,620

167 178 174 159 57 54 56 60 59 50

159 190 223 261 276 130 135 153 157 154 60 63 59 56 63

1,151 1,517 1,838 2,279 2,350

200 273 381 614

1,273 166 219 274 345 378 131 146 152 145 53 11 14 15 18 17

2,082 2,612 3,118 3,844 4,404

old age

71 77 85

102 149 19 21 23 29 42 49 58 67 96

173 42 52 52

• 72 125 21 28 36 38 10

219 292 382 660

1,548 31 42 57

101 240 32 42 57 97

225 46 50 60 88

202 3 4 5 7

14 488 612 763

1,201 2,562

children

18.3 17.8 16.8 15.9 11.7 23.1 20.9 20.2 18.6 23.1 29.4 27.9 25.1 21.6 13.2 25.4 23.7 22.1 20.8 15.4 18.7 17.1 17.4 15.5 20.7 33.4 31.8 27.8 22.7 8.1

45.2 44.4 41.8 34.2 13.1 35.9 32.8 29.5 25.7 20.2 21.4 20.0 18.6 18.0 113

26.9 25.6 24 5

' 22.0 15.2 32.4 31.3 28.5 24.4 11.3

Percentage

youth

15.2 12.1 11.8 11.2 27.9 14.5 15.0 12.8 13.1 8.2

17.8 16.7 16.5 14.8 12.8 14.7 15.6 15.0 14.0 13.4 15.4 12.4 10.6 11.6 13.5 20.7 17.5 17.9 15.6 14.8 19.0 19.5 20.0 20.6 21.5 19.8 18.8 18.2 16.2 13.7 14.5 13.6 13.2 12.0 18.2 19.3 15.6 15.7 15.3 17.4 19.1 17.1 17.5 16.0 16.7

adults

46.7 49.0 47.8 44.4 16.7 46.2 46.7 48.4 45.8 37.3 40.4 42.5 44.9 46.6 45.5 45.2 43.8 46.9 44.7 38.8 48.8 48.8 44.7 43.4 56.8 38.6 42.5 44.9 0.9

46.5 30.9 31.3 33.2 38.8 55.0 37.1 40.6 43.4 45.3 41.5 47.5 49.5 48.9 43.5 14.6 42.3 45.6 44.1 45.0 37.0 39.3 41.8 43.4 45.4 45.5

old age

19.8 21.1 23.6 28.5 43.7 16.2 17.4 18.6 22.5 31.4 12.4 12.9 13.5 17.0 28.5 14.7 16.9 16.0 20.5 32.4 17.1 21.7 27.3 29.5 9.0 7.3 8.2 9.4

13.8 30.6 4.9 4.8 5.0 6.4

10.4 7.2 7.8 8.9

12.8 24.6 16.6 16.9 19.3 26.5 55.9 11.5 13.2 15.7 17.7 30.4 9.2 9.8

10.6 14.2 26.5

children: 0-14 years, youth: 15-24 years, adults: 25-59 years, old age: ä 60 years.

110

Table 2. Estimated incidence of the population of each geographical area as a proportion (%) of the total population of the planet Earth.

Year

1990 2000 2010 2025 2050

Asia

56.4 57.1 56.9 56.2 52.2

Japan

2.3 2.1 1.8 1.5 1.2

America

North

5.2 4.7 4.3 3.9 3.7

Latin

8.5 8.6 8.8 9.0 9.5

Africa

12.2 14.0 16.0 18.7 23.9

Europe

Western

6.8 5.8 5.1 4.2 3.5

Eastern

2.2 1.9 1.7 1.5 1.4

USSR Méditer

ranean

5.4 7.5 4.9 7.2 4.5 6.9 4.2 6.6 4.0 6.3

Table 3. Estimated incidence (%) of the protein requirements for each geographic area upon the total of the planet Earth.

Year

1990 2000 2010 2025 2050

Asia

56.3 57.0 57.3 56.7 52.8

Japan

2.5 2.2 1.9 1.6 1.1

America

North

5.5 5.0 4.5 4.0 3.7

Latin

8.3 8.6 8.8 8.9 9.0

Africa

11.4 13.0 14.9 17.9 22.9

Europe

Western

7.2 6.2 5.3 4.4 3.5

Eastern

2.3 2.0 1.8 1.6 1.3

USSR

'5.6 5.1 4.7 4.2 3.9

Méditer

ranean

7.5 7.3 7.0 6.7 6.1

for age will remarkably affect the future alimentary policy, particularly that concerning the products of animal origin. The variation in the total population is highly differentiated in relation to the geographical area considered and the estimated incidence of each area as a proportion of the total population of the planet Earth, is shown in Table 2.

It is interesting to note that: (i) Asia reaches the maximum value in 2000 (57.1%) after which it starts to decline; (ii) Latin America has a progressive tendency to increase, actually reaching more than 600 million in 2010; (in) Africa shows a continuous increase of the population which reaches one quarter of the human population on the planet Earth in 2050.

Alimentary resources

Protein requirements

By considering the 'age' structure as well as the suggested standards (average g/d per individual in relation to the age class: 'Birth-14 years', 32; '15-24 years', 68; '25-59 years', 61; '> 60 years or more', 59), in the year 1990 the amount of proteins required is 101.186 million of tonnes; this value increases up to 119.816 in the year 2000, up to 139.884 in the 2010 (+ 38.0 per cent increase compared to today) and up to 204.721 million tonnes in the year 2050. The per cent incidence of each geographical area upon the total of the planet Earth of the proteins necessary to meet the needs of the human population is reported in the Table 3. The most significant temporal variation concerns Africa: it changes from the present 11.4% to 14.9 in 2010 and to 22.9 in 2050.

I l l

Table 4. Protein requirements (x 1,000) calculated on the basis of the human population as reported in Table 1 in some geographical areas, for different classes of age1.

Geographical area

Western Europe

Eastern Europe

Mediterranean Countries

Ussr

Japan

Asia

Africa

Latin America

North America

Oceany

Planet Earth

Year

1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050

Total

19,975 20,313 20,344 20,102 19,867 6,386 6,628 6,852 7,178 7,209

20,902 23,928 26,927 30,861 34,198 15,480 16,774 17,898 19,342 22,052

6,873 7,231 7,352 7,260 6,141

155,960 187,077 219,414 260,964 296,300 31,526 42,747 57,168 82,207

134,292 23,043 28,221 33,594 41,155 50,459 15,196 16,337 17,321 18,530 20,793

1,403 1,673 1,792 2,190 2,611

277,223 328,263 383,243 460,159 560,879

children

2,059 2,059 1,932 1,805 1,267

355 792 792 760 982

3,674 3,959 3,959 3,832 2,502 2,312 2,312 2,280 2,312 1,900

728 697 728 633 728

31,575 36,009 36,072 34,204 12,890 9,279

12,256 15,202 17,133 9,564 5,099 5,606 5,891 6,208 5,890 1,869 1,869 1,837 1,900 1,298

222 253 253 285 222

54,219 62,010 65,145 65,335 34,805

Amount

youth

3,658 2,981 2,913 2,710 6,436 1,152 1,220 1,084 1,152

745 4,742 5,081 5,556 5,623 4,878 2,846 3,252 3,320 3,320 3,523 1,287 1,084

948 1,016 1,016

41,937 42,208 49,796 50,270 50,677 8,333

11,518 15,582 22,019 33,672 6,030 6,910 7,791 8,401 8,537 2,710 2,710 2,778 2,710 4,472

339 339 339 406 542

68,495 77,425 84,823 92,004

109,755

adults

10,104 10,769 10,527 9,620 3,448 3,267 3,388 3,630 3,570 3,025 9,620

11,495 13,492 15,790 16,698 7,865 8,168 9,256 9,498 9,317 3,630 3,812 3,570 3,388 3,812

69,636 91,778

111,199 137,880 142,175 12,100 16,516 23,050 37,147 77,016 10,042 13,249 16,577 20,872 22,870 7,926 8,833 9,196 8,772 3,206

666 847 908

1,089 1,028

125,961 158,026 188,639 232,562 266,442

old age

4,154 4,504 4,972 5,967 8,716 1,112 1,228 1,346 1,696 2,457 2,866 3,393 3,920 5,616

10,120 2,457 3,042 3,042 4,212 7,312 1,228

. 1,638 2,106 2,223

585 12,812 17,082 22,347 38,610 90,558

1,814 2,457 3,334 5,908

14,040 1,872 1,930 2,574 4,212 9,535 2,691 2,925 3,510 5,148

11,817 176 234 292 410 819

28,548 35,802 44,636 70,258

149,877

children

10.3 10.1 9.5 9.0 6.4

13.4 11.9 11.6 10.6 13.6 17.6 16.5 14.7 12.4 7.3

14.9 13.8 12.7 12.0 8.5

10.6 9.6 9.9 8.7

11.9 20.2 19.2 16.4 13.1 4.4

29.4 28.7 26.6 20.8 7.1

22.1 19.9 17.5 15.1 11.7 12.3 11.4 10.6 10.3 6.3

15.8 15.1 14.1 13.0 8.5

19.6 • 18.9

17.0 14.2 6.2

Percentage

youth

18.3 14.7 14.3 13.5 32.4 18.0 18.4 15.8 16.0 13.6 22.7 21.2 20.6 18.2 14.3 18.4 19.4 18.5 17.2 16.0 18.7 15.0 12.9 14.0 16.5 26.9 22.6 22.7 19.3 17.0 26.4 26.9 27.3 26.8 25.1 26.2 24.5 23.2 20.4 16.9 17.8 16.6 16.0 14.6 21.5 24.2 20.3 18.9 18.5 20.8 24.7 22.1 22.1 20.0 19.6

adults

50.6 53.0 51.7 47.9 17.4 51.2 51.1 53.0 49.7 42.0 46.0 48.0 50.1 51.2 48.8 50.8 48.7 51.7 49.1 42.3 52.8 52.7 48.6 46.7 62.1 44.6 49.1 50.7 52.8 48.0 38.4 38.6 40.3 45.2 57.3 43.6 46.9 49.3 50.7 45.3 52.2 54.1 53.1 47.3 15.4 47.5 50.6 50.7 49.7 39.4 45.4 48.1 49.2 50.5 47.5

old age

20.8 22.2 24.4 29.7 43.8 17.4 18.5 19.6 23.6 34.1 13.7 14.2 14.6 18.2 29.6 15.9 18.1 17.0 21.7 33.2 17.9 22.7 28.6 30.6 9.5 8.2 9.1

10.2 14.8 30.6 5.8 5.7 5.8 7.2

10.5 8.1 8.7 9.9

13.8 26.1 17.7 17.9 20.3 27.8 56.8 12.5 14.0 16.3 18.7 31.4 10.3 10.9 11.6 15.3 26.7

children: 0-14 years, youth: 15-24 years, adults: 25-59 years, old age: > 60 years.

112

Table 4 shows the daily protein requirement of the whole population, distinctly for classes of age within each geographical area. During 20 years, the human population of the earth increases its daily requirements of 40 per cent. Such an increase is highly diversified from one area to another: in Africa it is 81%, in Latin America 46% in Asia 41% in the Mediterranean Countries 29%, in USSR 16% in Western Europe 7%, in Eastern Europe 2%.

The temporal variation for classes of age is of great interest because it shows how in the short-medium term (10-20 years) or, even better, in the medium-long term (> 20 years) the two extreme classes tend to modify remarkably their incidence upon the total protein require­ments: in fact, given the expected demographic development, the fraction of the class 'children' decreases from the actual 19.6% to 17% in 2010,14.2% in 2025, and 6.2% in 2050 while that of the class 'old age' increases from the actual 10.3% to 11.6% to 15.3% and to 26.7%, respectively.

Protein balance

By considering the demographic structure in the years 1980 and 2050, the average requirement per individual is 53.5 g/d; by considering that to meet protein requirements at least 50 per cent of the protein should be of animal origin, the average amount of 70 g/d per individual in the year 1985 (FAO, 1989) is superior to the amount of 60 g/d suggested by some authors, while the ratio between plant and animal proteins is too high (1.92). This simply means that for a more balanced level of protein ingestion it is necessary to increase animal production (especially meat) in order to reach nearly 10.635 million tonnes of protein pe/year globally while, simultaneously, there is a 'surplus' of nearly 28.351 million tonnes of plant proteins.

On the level of the single geographical area, the lack of animal protein especially concerns Africa and Asia. In 1985 the total source of proteins of animal origin was divided as follows: 8.5% as eggs, 34.1% as milk and 57.4 as meat. By considering the per cent contribution of each species we have: 47.7% for cattle, 21.9% for poultry, 21.4% for swine, 4% for buffaloes, 3.5% for sheep, 1.3% for goats and 0.2% for horses.

Calory requirements

By considering the 'age' structure and the suggested standards (average kcal/d per individual: 'birth-14 years', 1,394; '15-24 years', 2,550; '25-59 years', 2,525; '60 years or more', 1,850) the amount of calories which have to be available is 406.063 million Mkcal in the year 1990; this increases to 481.180 in the year 2000 and to 560.129 in 2010 (an increase of 38.0% compared to today), and reaches 785.590 in the year 2050. The percentage requirement (and its temporal variation) for each geographical area of the annual total for planet Earth of the calories to be ingested is practically identical to that of protein.

Table 5 shows the daily requirements of calories of the whole human population, distincdy for classes of age, within each geographical area. The temporal variation, total and for classes of age, follows the same behaviour already examined for the proteins.

Caloric balance

For the years 1980 to 2050 the average requirement per individual is 2,139 kcal/d. Even by considering an average value of 2,400 kcal/d, in 1985 there was an excess of availability equal to 547.522 million Mkcal/d. Also in 1985, the total amount of calories of animal origin was provided by 7.8% as eggs, 52.3% as milk and 39.9% as meat. By considering the per cent contribution per species, we have: 56% for cattle, 18.8% for swine, 15.5% for poultry, 5.9% for buffaloes, 2.4% for sheep, 1.3% for goats and 0.1% for horses.

113

Table 5. Requirements in Kcalories (x 1,000,000) calculated on the basis of the human population as reported in Table 1 in some geographical areas, for different classes of age1.

Geographical area

Western Europe

Eastern Europe

Mediterranean Countries

Ussr

Japan

Asia

Africa

Latin America

North America

Oceany

Planet Earth

Year

1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050 1990 2000 2010 2025 2050

Total

782 794 791 771 718 252 261 271 279 275 832 953

1,070 1,217 1,311

615 661 707 756 837 271 283 284 277 247

6,279 7,544 8,810

10,373 11,273 1,285 1,741 2,322 3,320 5,346

929 1,137 1,349 1,640 1,952

600 645 681 715 733 57 66 71 86 99

11,125 13,183 15,346 18,268 21,523

children

91 91 85 79 56 38 35 35 33 43

162 174 174 169 110 102 102 100 102 84 32 31 32 28 32

1,390 1,585 1,588 1,506

568 409 540 669 754 421 224 246 260 273 259

82 82 81 84 57 10 11 11 13 10

2,387 2,730 2,868 2,877 1,532

Amount

youth adults

138 112 110 102 242 43 46 41 43 28

178 191 209 212 184 107 122 125 125 133 48 41 36 38 38

1,578 1,589 1,874 1,892 1,907

314 434 586 829

1,267 227 260 293 317 321 102 102 105 102 168 13 13 13 15 20

2,578 2,726 3,193 3,463 4,131

422 449 439 401 144 136 141 152 149 126 401 480 563 659 697 328 341 386 396 389 152 159 149 141 159

2,906 3,830 4,641 5,754 5,934

505 689 962

1,550 3,214

419 553 691 871 955 331 369 384 366 134 28 35 38 45 43

5,257 6,595 7,873 9,706

11,120

old age

131 142 157 189 276 35 39 43 54 78 91

107 124 178 320 78 96 96

133 231

• 39 ' 52

67 70 18

405 540 707

1,221 2,864

57 78

105 187 444 59 78

105 179 417 85 92

111 163 374

6 7 9

13 26

903 1,132 1,412 2,222 4,740

children

11.6 11.5 10.7 10.2 7.8

15.1 13.4 12.9 11.8 15.6 19.5 18.3 16.3 13.9 8.4

16.6 15.4 14.1 13.5 10.0 11.8 11.0 11.3 10.1 13.0 22.1 21.0 18.0 14.5 5.1

31.8 31.0 28.8 22.7 7.9

24.1 21.6 19.3 16.6 13.3 13.6 12.7 11.8 11.7 7.8

17.5 16.7 15.5 15.1 10.1 21.4

' 20.7 18.7 15.7 7.1

Percentage

youth

17.6 14.1 13.9 13.2 33.7 17.0 17.6 15.1 15.4 10.2 21.4 20.1 19.5 17.4 14.0 17.4 18.5 17.7 16.5 15.9 17.7 14.4 12.7 13.7 15.3 25.1 21.0 21.3 18.2 16.9 24.4 24.9 25.2 25.0 23.7 24.4 22.9 21.7 19.4 16.4 17.0 15.8 15.4 14.3 22.9 22.8 19.7 18.3 17.4 20.2 23.2 20.7 20.8 19.0 19.2

adults

54.0 56.5 55.6 52.1 20.1 54.0 54.1 56.1 53.4 45.8 48.2 50.4 52.6 54.1 53.2 53.3 51.6 54.6 52*4 46.5 56.1 56.2 52.5 50.9 64.4 46.3 50.8 52.7 55.5 52.6 39.4 39.6 41.5 46.7 60.1 45.1 48.6 51.2 53.1 48.9 55.2 57.3 56.4 51.2 18.3 49.2 53.0 53.5 52.3 43.4 47.3 50.0 51.3 53.1 51.7

old age

16.8 17.9 19.8 24.5 38.4 13.9 14.9 15.9 19.4 28.4 10.9 11.2 11.6 14.6 24.4 12.7 14.5 13.6 17.6 27.6 14.4 18.4 23.5 25.3 7.3 6.5 7.2 8.0

11.8 25.4 4.4 4.5 4.5 5.6 8.3 6.4 6.9 7.8

10.9 21.4 14.2 14.3 16.3 22.8 51.0 10.5 10.6 12.7 15.2 26.3 8.1 8.6 9.2

12.2 22.0

children: 0-14 years, youth: 15-24 years, adults: 25-59 years, old age: > 60 years.

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Signs on the evolution of the agro-alimentary system

It is likely that the structure of the agroindustrial system will undergo shortly a deep reorganization process in order to answer the challenges of the variable world of the consumers. The 'multinationals' will have to change into 'multicultural' societies or, even better, into societies with multiple civilizations, as previously mentioned. It is also predictable that a more intensive use of information will determine a change in the institutions, mainly in the relationships among the decisional powers that are at different levels of organization.

Such a tendency towards the distribution of power will require institutional changes to be realized in a short period, otherwise there might be the possibility of conflict between the rate of technological changes and that of the institutional ones. The institutions present at the end of the 20th century are inadequate to handle the great technological innovations which can be utilized in the 21st century. Western Europe is in a position of advantage in the international market: from 1967 to 1987 the European share passed from 42 to 45 per cent of exports, that of USA from 14.4 to 9.7 per cent, that of Japan from 4.8 to 9.1 per cent. Compared to other real or potential competitors, Western Europe has a privileged position concerning the energy dependance as well as the cultural and scientific potential. The socio-cultural differences of Europe constitute a power, not a weakness, especially during unstable and uncertain historical moments. The European society can be considered as a biological system in which the internal differences contribute toward a dynamic adaptation to the external situations. Undoubtedly, the external factors are more influential in the agro-zootechnical sector than in other production areas. By keeping into consideration the actual complexity, the dynamicity ancf some basic uncertainties of the market, the management of zootechnical production has to be considered on a long-term scale. Globalization of the economy, production, supply and exchanges is a rapidly expanding reality, while the idea of marketing a given product globally by using the same marketing strategy can undoubtedly be considered as a myth.

As we move into the 21st century the basic conflicts of interests and the relationships between developed (e.g. U.S.A., EEC, Japan) and less developed regions (P.V.S. countries) of the world will accentuate. This will influence marketing strategies which should be able to foresee the so-called 'change waves' for which, in a given market, after an initial uniformity of the product, the interest deviates toward a segmentation and individualization of the product itself. The production, therefore, must be able to detect all those strategies capable of harmonizing massive production with the personalization of consumption. In this context, great importance must be given to the 'economy of the wishes' which doesn't interest only the consumer. All those concepts of guaranteed certainties have to be neglected, while all those initiatives tending to utilize present knowledge for a better understanding of the future have to be privileged, even if there might be some exposure to the risk of mistakes. Particular attention must be given to the regulation and to the certification of conformity of a given food product in order to ensure its 'total quality'.

Some thought on the quality of the products

The interest in the quality of a product is increasing. However, much can be discussed about the meaning of the term 'quality'. Some of the common characteristics could be the following: sensorial, chemical, biochemical, physical, functional, microstructural, microbiological and nutritional characteristics; safety, preservability, freshness ('shelf life'), but also such specifi­cities as appellation of origin and its control. Among these, the most important ones appear to be the safety, the sensorial characteristics (taste and flavour) and the freshness, followed by the acceptability of the price. Generally, it is not possible to define the concept of quality in a unique model, mainly because of the different meanings that the term 'quality' may have, in relation to the ethical and cultural variability of the human population and the lack of an

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acceptable relationship between the consumer and the producer. International competition may accentuate such discrepancies.The use of innovative biotechnology is affecting more and more the production processes and the characteristics of the products. Such a variation will have a marked effect upon the agro-alimentary system and, consequently, upon the production criteria of the basic products, including those of animal origin. The future foodstuffs will be very different from the basic ones because of their dietetic properties, processing of the basic materials and techniques for their conservation and distribution. All these major changes, even more accentuated by the use of microelectronics and process computers, will affect the techniques involved in the production of food of animal origin. This tendency, however, will have to be reconciled with the opposite wish of the consumer who will look for animal and plant food of specific quality and origin, less and less subject to manipulation. Probably, both tendencies will coexist in relation to the variegated reality of the human communities. The ongoing revolution, strongly driven by the instruments of hidden persuasion, is leading toward a progressive belief that the 'prepared meals', and so on, nullify time and space. Such a deep rooted socio-cultural modification will certainly affect the future production of foods. The new attitudes to food, based on the promise of freshness, healthiness, welfare, juvenile aspect, and so on, do not originate from the base but are imposed by the big centres of persuasive activity (advertising). In recent years, in the industrialized countries, the consumers are becoming more aware, thus orienting their choices toward natural and healthy food, asking for more varieties and satisfaction. The industry, therefore, is obliged to face the qualitative improvement of its products more than the quantitative one. This implies more dependance on scientific and technological innovation. Food technology must, therefore, take into consideration the conti­nuous changes on the levels of production, transformation, distribution of the products, as well as socio-economic changes, such as new eating habits and a different sensitivity of the consumer toward the healthiness of the food itself. Eating habits are changing very rapidly as a consequence of demographic trends and new life-styles; all this will affect the strategic choices for the year 2000. In fact, the following changes are underway: (a) increase of average life span with consequent ageing of the population; (b) increase of the cultural level; (c) increase in the 'single' population; (d) reduction in the number of housewives; (e) increase in free time.

It is estimated that in the year 2000 more than 50% of the meals will be taken out of the house, for which it is predictable there will be an increase in the use of pre-cooked or semi-cooked dishes. The ageing of the population will induce a reduction of the product varieties in favour of products of easy and rapid preparation, low in cholesterol and sodium chloride, rich in calcium and fiber. The cultural improvement will lead toward an increase of the demand for 'healthy' food which can satisfy the nutritional requirements of the different human populations. A remarkable increase of reconstituted foods from products having a fish or meat basis is also predictable. For instance, it will be necessary to produce a milk of high quality, diversified in relation to its destination (direct consumption, cheese transformation, industrial fractioning to achieve the different ingredients). Food safety will be a major consideration in the near future. In other words, the future production of food of animal origin will have to be planned in view of a 'total quality philosophy'.

Agro-alimentary policy

Several researchs have pointed out the great variability of eating behaviour within the various geographical areas under consideration. Such a variability also concerns the EEC for which the definition of lines of behaviour becomes urgent. The scientific progress in the area of human nutrition has reached very interesting levels; however, there is a need for more information concerning the relationship between nutrition and health, as well as the evalution of the nutritional quality of the food. By considering the main objective as 'protection and

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improvement' of the health of a single citizen, it is necessary to identify a series of dietetic models in relation to the availability of the foods, social and cultural conditions and eating habits in the geographical area. The future imperative, therefore, will be: 'safety in the overall quality'.

By taking into consideration the ageing of the population in the Western Europe the future food policy should consider as a priority the nutrition of the 'old-age' category. It is well established that: (a) ageing induces deep modifications of the organic functions, according to genetic and environmental factors, (b) complex pathologies arise, often asymptomatic, corre­lated to dietetic errors; (c) given the heterogeneity of the population, it is not possible to standardize the nutrition according to the class of ageing; (d) in gerontology, it is necessary to personalize the diagnosis and, consequently, the diet because the functioning of the digestive apparatus and that of the 'target organs' condition the metabolic homeostasis according to the nutrients which are furnished; (e) a wrong nutrition (excess or lack) accelerates ageing and stimulates the rising of 'age-dependant' diseases (eg. senile diabetes, osteoporosis, osteopat­hologies, neoplasia); (f) the presence of proteins in the diet is indispensable because they can slow down the process of ageing and can reverse the metabolic damage, even under a condition of low functioning; (g) the high biological value of animal protein favours the activation of the vital functions, especially those of the central nervous system; this system, by producing neurotransmitters and neuromodulators, modulates the sensation of hunger and satiety, and controls the psycho-neuroendocrine-immunological-metabohcal homeostasis which is re­sponsible for the psyco-physical welfare of the individual. As Hippocrates used to say 'make food be your medicine and medicine be your food'.

The diversity of the nutritional requirements of man in relation to age and to daily activity, which normally takes place in a given microenvironmental context, will affect more and more the future agro-alimentary policy. For the products of animal origin, some fundamental aspects are: (a) the high biological value of the meat proteins and the right equilibrium among the essential aminoacids make the meat an irreplaceable food for human nutrition; particularly important are the branched chain amino acids (BCAA) which are present in meat in the right proportion; (b) the chemical composition of a food is not capable of fully satisfying the nutritional requirements of an individual; (c) the breeder must be able to produce products capable of reducing 'nutritional conflicts'; (d) the possibility to have a large number of genetic types, indigenous and/or 'cultural', each adapted to a given ecological niche and capable of reaching optimal qualitative and quantitative levels in their performances; this will satisfy the enormous variability of the breeding environment, culture, tradition, social and institutional organization, economical and professional level as well as the scientific potential which characterizes the human community on this Planet; (e) in relation to the goals to be reached, emphasis should be given to the division of the phenotypic expressions which have to be modified in 'primaries' and 'secondaries'; (f) animal production tends to be realized more and more in a 'cultural' ecosystem for which the animal engaged in zootechnical production becomes more and more a 'subordinated' member within such an ecosystem; (g) the continu­ous scientific discoveries about the organization and functioning of the genome, with particular reference to the topology of DNA and RNA, make possible the manipulation of genetic material and, therefore, the definition of new productive processes; (h) the use of innovative biotechniques (IB) will enable production with increasing efficiency per animal unit; (i) the fifth industrial revolution (new Kondratieff cycle) will be characterized by the use of the 'IB ' which will enable to satisfy the diversified needs of humanity; (j) the 'IB' will certainly affect animal production organization especially for: (i) genetic improvement, with a special regard to the compatibility betwen 'genetic time' and 'economic time'; (ii) management of the existing and future feed resources that can be obtained with the use of IB in other specific production fields; (iii) geographical position of the breeding units engaged in zootechnical production, especially for the dualism 'intensive breeding' or 'extensive breeding' and utilization of feed resources of the so-called 'difficult' regions; (iv) structure of the zootech-

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nical unit and dynamicity of the zootechnical enterprise; (v) production strategies for quality assurance in line with the growing demand by the consumers for products in a cultural context so widely spread geographically, including the expected U.S. of Europe; (vi) the role and function of the zootechnical manager who must be capable to perceive and to achieve the suggested models of production; such models must be able to adapt themselves to the dynamicity and to the different productive realities for a more correct management of the indigenous plant and animal resources, as well as of the water and soil; the whole in an harmonic context capable of reconciling general and specific aspects (among these, the healthy ones) (an example can be the one suggested by Nardone & Matassino, 1989, for the dairy catde in subtropical arid area).

The indigenous types have an unmeasurable biological value and can represent a real gene bank from which it will be possible to get information in order to achieve products diversified in their qualitative and quantitative aspects; furthermore, they will be particularly useful for the utilization of large food resources, especially by using particular protein molecules (somatotropin, and so on) in dairy as well as in meat cattle. Some researchs have recenüy pointed out that the Podolian cattle reared in southern Italy provides a meat significantly more tender and lighter if they are kept freely in grazing areas instead of pens. The quality of the meat furnished by the Podolian cattle kept freely in grazing areas was more competitive than that furnished by the Friesian and crosses or Brown Swiss and crosses, reared on grid-floor or feed-lot (Matassino et al., 1989). The organoleptic peculiarities of the products furnished by the indigenous genetic types constitute an important element for their wide utilization in 'difficult' areas, also for the protection of a territory and its' traditions. It is also possible that, in a near future, animals carrying specific chromosomal rearrangements could be utilized for the production of meat with a dietary value superior to that of animals lacking such rearran­gements. Some preliminary indications would be in favour of this hypothesis. In cattle, there is a special chromosomal rearrangement known as 'Robertsonian translocation', which is extremely important when in the homozygous condition. In fact, the numerical chromosomal reduction (2n= 58, 56, and so on) without loss of genetic information, induces an increase in the linkage relationships and, consequently, an increase of the genetic variability, indispensable under conditions of natural selection, as well as for any programme of genetic improvement. In addition to the linkage effect, the Robertsonian translocation would play an important role for temporal adaptation and would improve the precision in the chromosomal segregation during meiosis. The 'in vivo' conservation and multiplication of these subjects has to be considered particularly useful, not only because they could give rise to new species or subspecies, but also because they constitute a genetic patrimony which could be useful in a near future (Matassino et al., 1985, 1989). At the research center of Circello (BN), Italy, a specific research programme on this matter is underway.

Tendencies

In all the societies consumption of animal products follows a behaviour which is characterized by five phases, stricüy connected to income. The concept of income doesn't have to be intended only as expense capability but also as 'life model', generally speaking, correlated to the modalities of formation, distribution and utilization of the income itself (Zucchi, 1983; 1990). The animal production derive from the transformation of plant products whose transformation coefficients are highly dependant upon the technological level of the farms: very low under primitive conditions, more favourable in modem situations. At the first levels of social development, the alimentary consumptions prefer plant products. Subsequently, in more advanced developmental stages, the demand for animal products increases more than propor­tionally with respect to the income. To a third phase, characterized by an increase of demand which is less than proportional with respect to the evolution of the income, follows a fourth

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phase in which there is a substantial stagnation of consumption. Lastly, there is a fifth phase, typical of the countries with high income, which is characterized by a quantitative regression of the demand for food of animal origin. At the end of the third phase and, increasingly, in the fourth and fifth phases the qualitative demand is increased for the intrinsic as well as for the extrinsic components (incorporated services) of the product. Such references are true for the population in its complex as well as for the single social classes. Therefore, in a given population in a given historical period, behaviours of demand at different evolutionary stages coexist. In a wide sense, it can be generalized that in the first three phases of development the quantitative demand is prevailing, whereas in subsequent phases the qualitative demand becomes dominant. This aspect requires an increase of the expense for the consumption of animal products. Under an historical prospect, the supply shows a delayed tendency to adapt itself to the demand, mostly in the second and third phases. The productive apparatus, strongly stimulated by the comparative price system, reaches the maximum supply capability in the phase of stagnation of the consumptions and maintains a tendency to increase for some time, bringing upon itself a production 'surplus' which stimulates protectionist policies and forced international exchanges. The reconversion of the production apparatus toward more restrained supply volumes and qualitative answers is a condition 'common' to those societies which live in the fourth and fifth phase. In the world context, at the beginning of the 3rd millennium, wide socio-geographic areas exist which can be identified and recognized in each of the five phases already mentioned. In order to interpret the various adjustments which can represent a minimum common denominator, it is important to examine the mechanisms of development. The utilization of resources (natural, work, capital) evolves in relation to the relative economic productivity which can be achieved as function of their alternative uses: the most profitable uses attract the productive factors from the less profitable ones (Zucchi, 1986). The price factors tend to stabilize themselves at the most profitable levels of utilization. The productivity and social acceptability of the non agricultural activities (from the secondary to the quaternary sector) is usually high, with strong indexes of increments due to technological advancements. These, in fact, affect the economic pattern and the price/cost/income ratios also for other sectors. As a consequence, the agricultural activities (including the zootechnical ones) must evolve coherently to the socio-economical system in order to maintain an acceptable level of balance with other activities. Every developmental stage has its own levels and specific disposition which may change if the reference pattern changes. Advances or excessive delays with respect to the equilibrium conditions are negatives. This means that the simple transpo­sition of technological models out of balance with the socio-economical realities can be very dangerous. The Table 6 reports the variation in the number of animals reared per inhabitant over the last 18 years.

Table 6. Variation in the number of animals reared per inhabitant over the last 18 years.

Year

1970 1975 1980 1985 1988

Cattle

0.29 0.30 0.27 0.26 0.24

Buffaloes

0.03 0.03 0.03 0.03 0.03

Sheep

0.29 0.26 0.25 0.23 0.23

Goats

0.11 0.10 0.10 0.10 0.10

Horses

0.02 0.02 0.01 0.01 0.01

Pigs

0.15 0.16 0.18 0.16 0.16

Poultry

1.28 1.49 1.41 1.77 1.97

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A clear reduction of the number is noticeable in most species, with the clear exception of poultry and to a lesser extent pigs. Such a trend concerns nearly all the geographical areas considered; some exception concerns the swine species for Europe and Africa, the goat for Oceania and the horse for North America. From this interpretative pattern it is possible to derive a series of economically similar areas in order to get answers to the questions posed by the theme.

Western Europe

The most important aspects of this area are as follows : (a) stagnation of the quantitative demand of animal products with a regressive tendency; (b) high increase of the qualitative demand for intrinsic characteristics (healthiness, nutritive components as function of diets, etc.) as well as for the incorporation of services (technological qualities, transformation, conservation, distri­bution and consumption). The price will maintain a strong influence on the choices but will also be highly linked to qualitative warranties. The demand will have to be analyzed in a context of transnational area (for instance, EEC) with some degree of intensification of the exchanges within the area.

The inter-area exchanges of the surplus will become more and more difficult. The protec­tionist policy among the areas will assume increasing modulations with a decreasing tendency. The supply, where there is surplus, will have to be reduced. The environmental problems as well as those of the production ethics will assume increasing importance. Similarly, the social appreciation of the working conditions will assume increasing importance, even to becoming the limiting factor. The strong competition of the extra-agricultural sectors for the utilization of the resources (natural goods, capitals, work) impose the realization of high and dynamic indexes of productivity which can be realized through a strong incentivative for biotechnolo­gies of the second and third generation, as well as of new adequate organizational estab­lishments.

While the processes of intensification tend to become dominant, the extensification ones are economically valid only where suitable natural resources are abundant together with advanced zootechniques, whose goals are not only productivity, with strong direct (income) and indirect (social services) supports. In conformity with the evolution of demand and adaptation of the supply, the integrated productive forms will spread according to a continuous scheme of control of production (quanti-qualitative) as well as of distribution and control of the risks.

Eastern Europe and USSR

This area is of average development but with a very peculiar situation. The deep changes which are underway are not easy to interpret for the economical aspects. However, some indicators may be recognized in order to formulate some realistic hypothesis: (a) the available resources are quite large compared to the density of the population, (b) the demographic increase is positive and should continue as such (Table 1), (c) the productivity ratios among the various sectors are less discrepant than in other areas and located at medium-low levels, (d) the social and cultural levels are medium-high with strong tendency to improve, (e) the human resources are underoccupied compared to their potential and the incidence of the agricultural population is increased; therefore, in the process of development the classical and physiological transfer toward the secondary and tertiary activities will be more pronounced. This will give rise to complex adaptational problems whose characteristics will be highly affected by the political-economic models which will prevail, particularly the market bonds and the resource transfer. An acceleration of the developmental processes is conditioned by the improvement of international relationships which, by themselves, impose the search for equilibrium in the balance of payments of these countries. This equilibrium is, basically, bound by the export

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capabilities which, in the short-medium range, will regard only the primary goods (energy and agro-zootechnical products).

In such a context, the internal demand for animal products can be located between the second and the third phases, as previously indicated. As far as the supply is concerned, in these countries the livestock patrimony is very high if compared to-the Communitary indexes 'conventional adult head/inhabitant' but it realizes a very low productivity. There are quite wide possibilities for zootechnical.improvement, even though such possibilities are strongly correlated with the structural and institutional conditions. In a more advanced perspective, this area could not only satisfy the internal demand but also propose itself as structural exporter. By taking into account the territorial and environmental variability it is conceivable that the intensive (especially for the milk species and monogastrics), the extensive and semi-extensive directions will find a wider scope.

Southern Mediterranean area

The characteristics of this area can be identified in those of the second and third phases, with strong demographic problems and deep needs for a technical improvement of the resources. The main problem is the transferring of appropriate IBs in a context which can be highly improved.

Japan

This is a high development area whose general characteristics are similar to Jhose already described for the Western Europe. In this area, the demand will be expansive and strongly linked to the price ratios among the animal products, among which fish will maintain a relevant incidence. The supply will be stimulated by this favourable market condition, mostly for the intensive production of poultry, pigs and fish. The protectionist policies will remain and the exchange ratios, mainly on import, will be conditioned by such policies. These countries will maintain an important role for the absorption of the surplus coming from the North American, Australian and European areas.

Middle Asia

This area is, in general, the most crowded in the world and expresses political-institutional realities very different from each other and in evolution. The stages of development, however, can be inserted between the first and the third phases of development of demand. The demographic increases will continue to be high. The economic equilibriums will be very precarious with strong pressure on consumption. The demand potential is enormous but its exploitation is linked to the evolution of the whole economic system, and in such a context the zootechnical supply is a dependent variable. The religious and traditional components have a marked importance in this area; consequently, the zootechnical development is considerably affected. In the short and medium range, the use of working animals will be remarkable. In these countries the potential of the natural resources is remarkable but their zootechnical exploitation is extremely low, not only because of the traditional and religious bounds but also for the lack of cultural and technological basis and investment capabilities. The international exchanges of animal products arise from economical and political needs, for which the export flood remains significant; streams of imports in the short and medium range cannot be foreseen at this moment.

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Africa

This area is absolutely the most difficult, being characterized by a low-medium low degree of development The strong environmental limitations have established very delicate equilibri­ums which, quite often, have been put in to crisis by the pressure of the progress, without the possibility of establishing new equilibriums. The analysis of such problems is extremely complex; in these countries the evolutionary choices must be done with prudence by avoiding general applications, and even worse, imitations. This area can be located in the first or second phase of developmentThe demographic increases are and will be strong, for which the demand, essentially quantitative and for fundamental foodstuffs, will find dramatic limitations within an indigenous, inadequate supply, with the impossibility of imports from international solidarity. The production pressure, if not correctly performed, may aggravate the sterilization of resources. The active presence of these countries in the international exchange system of animal products is foreseeably difficult. The zootechnical initiatives toward this area should consist in expanding the knowledge, properly adapted, in order to enhance that already existing, to reduce wastage and, subsequently, to introduce innovations, by maintaining the general equilibrium. It is quite evident that the extensive and semi-intensive trends have to be preferred, while the intensive ones, except in particular cases, can be chosen in the short and medium range. For this area, the strengthening of the supply for plant and animal products is a priority under the optic that animal production should not be competitive with plants, thus allowing the equilibrium between the two sources to be achieved. In the most advanced countries and, in the future, also for the less developed ones, processes of intensification of production can be hypothesized; these have to be based on the use of techniques suitable to each specific situation. It is, therefore, important that, in these countries, a diffuse research activity be developed, finalized to the identification of appropriate choices and to the realization of formation and reference centres (Nardone & Matassino, 1989).

Latin America

This area is characterized by unstable, highly contrasted situations among the countries and within each country. With notable natural resources and low demographic density, this area always had a high zootechnical incidence of an extensive nature. Brasil and Argentina are the most significant examples. For these reasons, the middle-south american area has a strong position as an exporter of animal products, thus providing a remarkable stimulus for the economical equilibrium of the various countries and for their general economical development. The logics of the development for this area can be focused, particularly, on the abbundance of natural resources, and on the scarcity of capital, concentrated in huge urban areas where contradictions become evident between extensivism and intensivistic congestions. For south America there are no problems concerning the quantitative satisfaction of the internal demand while it is not so for the remaining areas of central America. There are important problems of production efficiency in order to support the export and the 'quality/price' competitiveness exerted by the developed areas. For these reasons, regardless of the great natural potential, the differentiation between the extensive trends in meat production (cattle but also sheep) and the intensive ones in milk, swine and poultry production (linked to the big urban areas) will be increased. Such a productive dichotomy requires different scientific and approaches in application which may lead this area to become an interesting zootechnical laboratory. As far as the international exchanges are concerned, the perspectives are linked to the evolution of the GATT negotiations and, therefore, to a modification of the protectionist policies and to the penetration from the developed countries.

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North America

For this area, the same considerations expressed for the Western Europe are valid.

Oceania

This area is characterized by the excess of natural resources and scarce population, the latter constituting a limiting factor for the exploitation of its large productive potential. The demographic increase (Table 1) due mainly to immigration, will not bring substantial changes in the situation. The present developmental model will, most likely, stabilize by expressing two opposite tendencies in equilibrium: (a) intensive production (dairy cattle, swine, poultry) will develop further in areas with high demographic densities, in connection with needs of socio-economical and distributive balance and (b) extensive production (mainly sheep-goat) will remain by utilizing innovative techniques for genetics, prophilaxis, working conditions and productivity. The area will maintain a precise export position, potentially expandable in relation to the possibilities of absorption from the international markets.

The oil rich Middle East

This area has very peculiar characteristics because the oil resources feed a very high income level which, even though is erroneously distributed, pushes toward developmental models in an area deeply rooted with traditions. The strong profit of the currency balance is pushing toward policies of subventions in favour of food production while keeping opened noticeable amounts of importations of animal products and tools for animal production. The interest of the developed countries toward this area is relevants, mainly because it feeds several inter­changeable streams. Also in the future such a model will persist. Therefore, it will be necessary to realize techniques suitable to the environment, while the attention toward the extensive activities will decrease, mainly for sociological reasons. All the animal species (with the exception of the pig for religious reasons) are involved, particularly poultry and sheep. The level of consumption may be located between the second and the third phase, with a strong tendency toward qualitative improvements.

Conclusions

1. For the year 2010 the human population on the Planet Earth is estimated to be around 7.2 billion, with an increase of nearly 2 billion with respect to today (Figure 1 and Table 1). The demographic structure for age varies over time: the incidence of the class 'birth-14 years' tends to decrease (especially after the year 2010) while that of the class '> 60 years' shows a positive trend which becomes more pronounced after the 2010 (Table 1). The total variation, as well as that for age, is different in relation to the geographical area.

2. In the 2010, the population present on the Planet Earth will need 383.243 t/d of protein of which at least half must be of animal origin (Table 4). Therefore, in 20 to 25 years, animal production must be able to furnish 69.942 million of ton of proteins per year. By considering that, in 1985, the availability of such a proteins was only 42.526 million tonnes, the zootechnical manager must be able to produce other 27.416 million tonnes of animal proteins. The solution of the problem is different in relation to the geographical area considered (Table 3).

3. In the reorganization of the agro-industrial system it will be necessary to consider the passage from the 'multinationals' to the society with 'multiple civilizations'. Particular attention should be given to the on going demographic trend (increase of the average

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lifetime of man) for its effects on the production of foodstuffs which have to be of easy digestibility, low in cholesterol and sodium chloride, rich in calcium and fibre, healthy and with high safety levels. Any foodstuff, therefore, of animal origin or not, must be produced under the philosophy of the 'total' quality.

4. Some of the barriers affecting animal production are as follows: the disequilibrium of demographic development, uncontrolled migrations, unemployment, metamorphosis of the job, changes in life styles, establishment of autonomist as well as ideological-religi­ous tendencies, instability of the international political scenario, with particular reference to the PVS which are geographically more represented, total lack of uniformity in the growth of the sociocultural/economic level, environmental degradation, economical interdependence among the countries, competition, specialization of the culture and of the economy, crisis of the relief State, energy availability, different rate of acquisition of knowledge and its utilization, diversity among countries in health policies.

5. The innovative biotechniques will play an increasing role not only in the developed countries but also in the underdeveloped ones. Particular attention will be given to those enterprises which will be able to reduce the costs of investment. The animal and plant productivities can increase remarkably by diversifying the genetic types. Such a diver­sification can be achieved by utilizing the 'traditional' criteria as well as the recombinant DNA technology. It is, in fact, known that DNA manipulation is a powerful tool to increase the genetic variability which is decreasing because of the human intervention on the natural ecosystem. The same vulnerability to the environmental stressors of the limited number of genetic types utilized today may noticeably decrease by using revolutionary technical innovations such as the so-called 'microtechnology'. Such a technique will allow the realization of molecular computers able to drive programmed vascular mini-submersibles in order to destroy undesirable organisms (bacteria, viruses, and so on). The contribution of 'IB' will be remarkable in overcoming sanitary barriers, especially for the exchange of animal germplasm of high productive and reproductive efficiency. The possibility of modifying a living being (plant or animal) poses questions to which is not easy to answer. We believe that the search for a compatibility between the satisfaction of the human beings and a 'fair' respect of the biology of the other living beings must always drive the scientist who is utilizing the innovative biotechniques.

6. The rules for the utilization of pesticides will affect the productivity of the plant species and, consequently, the production of foodstuffs for the zootechnical enterprise. Even though it is not possible, at the moment, to foresee the effects of such rules, it is reasonable to predict a drastic reduction in the use of pesticides.

7. The agricultural activity is an intervention upon nature because it changes some of the characteristics of the environment. Such modifications, normally, affect positively the management of the ecosystem and the conservation of the natural resources. In particular circumstances, it will be necessary to search for a fair equilibrium between productive activity, environmental protection and social disposition.

8. Animal production will be more and more conditioned by the investment policies adopted by international enterprises in order to reduce die costs of production. Therefore, in addition to joint ventures, production agreements will play an increasing role.

9. There is a tendency towards a gradual and balanced reduction of national interventions for supporting production, as well as for a higher reliability among the nations in order to reduce the instability and the inbalances of the world agricultural market.

10. Europe has its own specific problems but its zootechnical future cannot be considered out of the evolution of the world scenaries where it can participate as an exporter of innovative biotechniques.

11. It is not possible to identify an homogeneous world trend, but several trends can be identified in equilibrium with the different phases of historical evolution of the various

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areas. The most advanced countries express situations to which, 'mutatis mutandis', the underdeveloped nations will move, as long as they will evolve.

12. The per-capita income is the most significant reference to define the stage of develop­ment and, therefore, the characteristics of the demand and the methods supply. The concept of income does not have to be based only in monetary terms but, mostly, as a socio-economic model. In more advanced stages, the qualificative demand (intrinsic and technological characteristics of the products, healthiness, incorporated services) assu­mes more relevance.

13. The price factor (and consequently the cost of production) cannot be considered in absolute terms but has to be correlated to the previous aspects. In this sense, also the concept of competition has to be elaborated.

14. The sanitary barriers should be reduced even though they might always represent an instrument of protectionist policy, especially for exchanges between countries with different levels of development.

15. The degree of transformation of animal products will increase, thus imposing more integrated organizational forms, according to the criteria of coherence regarding orga­nization, research, production technologies of transformation, distribution, etc.

16. The innovative policies should be modulated according to the realities they face: they should tend to balance (if not to increase) animal production to the other economic activities, at least for the following four aspects: acceptibility in the consumer's scale of values, comparative profitability, social acceptance of the production processes, respect of the environment.

17. For the developed Europe, the zootechnical concept should be more and more connected to the objectives and strategies which are formulated by the production segments located at consumption levels. In the meantime, the zootechnical enterprise will be more and more linked to social and environmental bonds.

18. The true challenge to our knowledge, probably, can be identified in the capability to transfer, daily, in the operational sector the conclusions of this meeting.

19. It is necessary to reduce the sources of uncertainty but it is also indispensable to face the future research with a systemic approach which has to become an existential philosophy of the breeder. In this context, great importance is attached to the acquisitions capable of improving the strategic thought, expecially in times characterized by uncertainty and deep socio-political changes. The level of professionalism and the intuitive sensitivity can be considered as two non-interchangeable elements for leading production devel­opment. Such a sensitivity has to become a 'sixth sense', capable of providing elements of evaluation for managing with 'art' the enterprise during times of constantly mutable challenges.

20. Particular attention must be given to a critical revision of the didactic and pedagogic criteria, in order to prepare a figure of professionism having also critical and strategical capabilities.

21. The ambition to foresee all the future is too presumptuous; the image of the forest that moves forward is not in Macbeth's madness if it is interpreted as the variation of the invariances in the medium-long period; but Macbeth's metaphor cannot go beyond it, otherwise his madness becomes ours.

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References

FAO, 1982. Production Yearbook 1981, vol. 35, V-306. FAO, 1988. Production Yearbook 1987, vol. 41, V-351. FAO, 1989. Production Yearbook 1988, vol. 42, V-350. FAO, 1989. Comprehensive demographic estimates and projections. 1950-2025,1-194. I.T.P.A., 1987. Per una sana alimentazione italiana. Roma, 3-1971. MacArthur, R.H. & Wilson, E.O., 1967. The theory of Island Biogeography, Princeton.

University Press, Princeton. Matassino, D., 1986. II contributo della selezione per una produzione commerciale nell'alle-

vamento del bovino da latte. Atti Conv. AIA XLI Fiera int. bovino da latte, Cremona, 26 settembre.

Matassino, D., 1988a. II bovino: la produzione del latte oggi e domani. Atti tav. rot. su 'Ü bovino al servizio dell'uomo, quali prospettive per il 2000?', Parma, 12 dicembre. Giorni, 74, n. 2,22, suppl.

Matassino, D., 1988b. II future delle biotecnologie nelle produzioni animali: alcuni aspetti scientiflci e tecnici. Prod. Anim., 1, in Serie, 35.

Matassino, D., 1989. Biotecnologie: applicazioni e prospettive. Italia agricola, 126(3):101. Matassino, D., Di Berardino, D. & Lioi M.B., 1985. Anomalie cromosomiche nel bovino

podolico allevato in Italia meridionale. Prod. Anim., 4, n.s., 55. Matassino, D„ Nardone, A., Grosso, F. & Zullo, A., 1989. II bovino podolico: ieri, oggi,

domani. Taurus, 1(6):101. Nardone, A. & Matassino, D., 1989.1 sistemi di allevamento bovino per la produzione di latte

nel subtropico arido: alcune ipotesi di intervento su larga scala. Prod. Anim., 2, HI Serie, 1.

Zucchi, G., 1983. Orientamenti di politica alimentäre in rapporto ai processi di produzione, trasformazione, distribuzione. Atti Conv. 'Nutrizione, ambiente, lavoro', Modena, 53.

Zucchi, G., 1986. Problemi e prospettive degli allevamenti zootecnici in Italia. Accademia Nazionale Agricoltura, 450.

Zucchi, G., 1990.1 consumi alimentari in Italia. Analisi comparativa. Atti Conv. Associazione Italiana Alimentäre. (In corso di stampa).

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European animal husbandry: a model to adopt or reject by developing countries?

H. Jasiorowski

FAO, Agricultural Department, via délie Terme di Caracalla, 1.00100 Roma, Italy

Summary

Western European models of animal production in general are feed grains and capital intensive. Production systems are commercially oriented with emphasis on product quality, uniformity, shelf life and shelf availability. European Livestock production is further characterized by EC subsidies and/or market regulations (import quotas) to protect its livestock producers. In general terms it can be argued that the European livestock production industries have been shaped more strongly by economic, social and political forces within Western Europe than by considerations of biological efficiency, technical sustainability or environmental protection. The situation of the developing countries is quite different and consequently the European models of animal production are not and cannot be suitable to the developing world. Animal production in developing countries faces very serious problems. In spite of consistent growth in overall production, average per capita consumption of animal products remains low and neo-static for decades, mainly due to increasing human population. However, the increased meat and milk production in developing countries is largely due to increased livestock num­bers, and not to increased productivity; clearly this trend cannot continue. The rapid develop­ment of poultry and pig production in developing countries is clear evidence of the demand for animal products; however, this in turn has raised the demand for imported feedstuffs. Meat and milk imports have also expanded in response to consumer demand which has been cul­tivated in some countries through food aid or export dumping of surplus production in in­dustrialized countries. Asa result the total import of livestock products continues to rise steadi­ly. Faced with this situation it is not surprising that decision makers in developing countries look with admiration on livestock production models in Europe and often try to copy them. Generally the results have been very disappointing. Their dilemma is one of time—the urgen­cy in time to increase animal productivity to meet the increasing human demand for animal products but avoiding the time lag (and investment) necessary to develop their own livestock development technologies. It is argued in this paper that many of the technologies which underpin European livestock production can be adapted to meet developing country needs provided realistic development rationales are followed and the development strategies are properly phased. The effective adaptation of reproduction (including AI and ET) selection, nutrition and animal management technologies to suit developing countries, is discussed in the paper and examples of successes and failures are quoted. The sustainable development of livestock production is also discussed in reference to social, economic and environmental sustainability.

Résumé

Les modèles ouest-européens de l'élevage sont généralement fondés sur une alimentation à base de céréales et des investissements importants. Les systèmes de production sont de type commercial et mettent l'accent sur la qualité, l'uniformité la conservation et la disponibilité des produits. L'élevage européen est caractérisé par des subventions de la Communauté euro-

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péenne et des réglementations commerciales (quota d'importation) pour protéger les produc­teurs. En gros, on peut dire que les entreprises européennes de l'élevage ont été plus fortement influencées par des facteurs économiques, sociaux et politiques propres à l'Europe occidentale que par des considérations d'efficacité biologique, technique ou de protection du milieu. La situation dans les pays en développement est sensiblement différente et les modèles européens de production animale n'y sont pas et ne peuvent pas y être utilisés. La production animale y rencontre des problèmes très difficiles. En dépit d'une croissance continue dans la production totale, la consommation moyenne par habitant de produits animaux est restée faible et presque stable, principalement du fait de l'accroissement de la population humaine et la production croissante de viande et de lait y est en grande partie due a l'accroissement du nombre d'animaux et non à l'augmentation de la productivité; cette tendance ne peut évidemment se poursuivre. Le développement rapide de la production de volailles et de porcs dans les pays en dévelop­pement montre clairement la demande en produits animaux; en revanche, ceci entraine un ac­croissement des importations d'aliments pour animaux. Les importations de viande et de lait ont également augmenté pour répondre à la demande des consommateurs qui, dans certains pays, a été influencée par l'aide alimentaire ou les exportations de dumping des surplus des pays industrialisés. Il en résulte que les importations totales de produits animaux continuent d'augmenter fortement. Face à cette situation, il n'est pas surprenant que les dirigeants des pays en développement admirent les modèles d'élevage européen et essayent de les copier. En général, les résultats sont décevants. Le dilemme se pose en termes de temps. L'urgence d'ac­croître la productivité animale pour satisfaire la demande humaine tout en évitant les délais (et les investissements) nécessaires à la mise aux point des technologies de développement de l'élevage. Ce rapport démontre que de nombreuses technologies qui supportent l'élevage européen peuvent être adaptées pour, satisfaire les besoins des pays en développement, pourvu que des critères réalistes de développement soient suivis et que les stratégies de développement soient mises en place correctement. Il considère l'adaptation effective des technologies de reproduction (y compris l'insémination artificielle et le transfert d'embryon) de sélection, de nutrition et de gestion, aux besoins des pay s en développement et il cite des exemples de succès et d'échecs. Le développement de l'élevage est également envisagé en comparaison du développement social et économique et de l'environnement.

Introduction

It was suggested to me that the title of my paper be followed by a question mark. Really, it represents a very difficult question. It first glance the answer is easy, but in fact I am almost sure that if we held a referendum among specialists an equal number would be eager to answer yes as no. The more cautious would reply "It depends".

For those, however, who deal with the problems of assistance to livestock development in the Third World this question is a night-mare. On the one hand they are under great pressure from the authorities in developing countries, from some bilateral aid authorities in developed countries and from powerful private companies, to transfer quickly and on a large scale tech­nology, livestock and sophisticated equipment from European countries to the poor, needy African and Asian countries. But on the other hand they know that if it is not done in acontrolled manner, it may in many cases finish in disaster.

Yet the poor countries badly need advice and help, and hundreds of millions of dollars are available yearly for assistance to livestock development in developing countries. Frequently aid is conditioned by purchasing certain technologies. Those responsible must take decisions, and often they cannot allow themselves to have doubts. In concrete circumstances they have to answer yes or no taking into account, of course, all the factors surrounding the reply "it depends". It is hoped that the discussions provoked by this presentation will help all those colleagues who either work in the developing countries or in the international or bilateral

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Table 1. Resource per caput.

Developed Developing

Agricultural land ha:1

per person 1.6 0.7 per person econ. active in agric. 35.9 2.7

Animals per 100 ha. of agric. land livestock units2 36.6 54.9

Animals per person livestock units2 0.57 0.39

Animals per person active in agric. livestock units2 13.1 1.5

1 This includes arable land, permanent crops and permanent pastures. 2 Livestock units have been calculated as: large ruminants and horses 1.0;

small ruminants 0.1; pigs 0.5; poultry 0.01.

technical assistance organizations and who are eagerly looking for the answer to the question which is the title of this paper.

Resources for livestock production in developing countries

The so-called developing world is inhabited by almost 4 billion people, which is about 76 percent of the world's human population. This is a lot of mouths to feed.

These people have at their disposal 42 percent of the total world territory and about this same percent of the world's agricultural land. Per capita it is about half as much as in the deve­loped countries. In addition let us remember that the developing countries territory is located in the tropical and sub-tropical climatic region with all the problems it creates for agriculture and livestock production.

The developing countries have almost 70 percent of the world's ruminant population, 60 percent of pigs and 53 percent of poultry. Again, per caput, people living in developing coun­tries have much less animal resources than the people in developed countries but this is also coupled with lower productivity. It is worth remembering that livestock in developing coun­tries, in addition to providing meat, milk, wool, and hides serve as an important source of draught power — for land cultivation as well as for transport.

It is interesting to note that when the land and animal resources are calculated per person economically active in agriculture, the ratio between developed and developing countries is about 10:1. It means that per person working in agriculture in developed countries there is ten times as much land and animals as in developing countries (Table 1). It shows that the main resource in developing countries is labour, and this should be always borne in mind when considering the problem of matching resources with production systems.

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Current livestock production situation in developing countries

Let us have a short look at the really desperate situation in which livestock production finds itself in developing countries. These are the facts. 1. Despite of a total production increase for meat of 4 percent arid for milk of 3 percent per

annum, the average consumption of animal products per caput in developing countries is low and practically unchanged for decades. For example, the average meat consumption percaputin 1970was 12kg, and in 1985 13 kg. This is mainly due to the population increase (2.5 percent per annum).

2. The total production increase of meat and milk in developing countries is mainly due to the increase in number of animals (1.5 to 5.0 percent per annum depending on species) and not to an increase of their productivity. It is obvious that this trend cannot continue.

3. The increasing demand for meat in developing countries was the reason for the rapid deve­lopment of poultry and pig production with the ruminant sector remaining rather stagnant. This, however, raised the demand for imported feedstuffs. During the last twenty years the net grain imports to developing countries has increased from 20 to 150 million tons annual-iy.

4. The newly created demand of the better off urban population for meat and milk created the necessity for imports. The total import of livestock products is steadily and rapidly rising. In the mid-seventies the value of meat and milk exports from developed to developing coun­tries was 11 billion US dollars, but in the mid-eighties it was 21 billion.

5. The developed countries' food aid policy and subsidised animal production export policy frequently discourages development of local production in developing countries. In some West African countries the price of meat imported from Europe is sold at half the price of the locally produced meat.

6. Income elasticity of demand for livestock products is usually high, even up to 0.97, for meat in Asia and the Far East, but the very low standard of living provides little scope for increased local consumption. Controlled prices in many developing countries does not pro­vide enough incentive to producers, and export possibilities are hampered by animal health restrictions.

Such are the facts reflecting the livestock production situation in developing countries. Many old arguments could be quoted here showing that the perspective for the future in this respect is also not rosy (Jasiorowski, 1973). In the meantime, as we all know, animal production in the developed countries has progressed significantly. The rapid increase of production and productivity of animals can not be matched by increasing consumption, which leads to huge troublesome surpluses or to curbing production. Can the world tolerate such a situation for long, that about 25 percent of the world livestock resources produce too much and 75 percent far too little?

Attempts to improve the situation

The main responsibilities for improving the dramatic situation- of developing countries lies naturally with the national governments, and they try desperately. However, in most cases, facing an almost catastrophic overall economic situation with thousands of needs and very little resources, and with a growing debt nightmare, they objectively cannot do much without international assistance. This can, however, never be on a scale sufficiently large enough, and even if well organized and perfectly allocated can only help marginally.

In addition to many bilateral programmes, the major international organizations assisting livestock development in these countries and helping in technology transfer are FAO, UNDP, and the World Bank. Since 1972 UNDP has financed very many livestock projects at a total cost of US $275 million. The World Bank has until now lent US $4 billion of which 350 million

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went to livestock projects in developing countries. To this should be added substantial assis­tance provided by developed countries on a bilateral basis and loans/aid from other banks.

In general there is a strong feeling that international assistance for livestock development did not meet expectations. This is mainly due to a completely uncoordinated aid policy by different organizations and developed countries, a lack of stability-in economic policy, insuffi­cient producer incentives and price controls in receiving countries. In many cases an uncritical transfer of developed countries ' technology without enough attention given to local production systems should also be blamed. This all discouraged the main investors. For example, 20 years ago the World Bank livestock share in agricultural loans for developing countries was 20 percent; now it is 8 percent In the same period UNDP livestock expenditures have declined from 25 million per year to about half that level (Brumby, 1988).

What I have said above is alarming enough and the authorities responsible for these coun­tries are looking at every possibility of increasing animal production and improving animal productivity as quickly as possible. Local resources are not enough and they naturally look for outside assistance. Many of these people (Ministers and others in authority) when visiting developed countries are highly impressed by the beauty and high productivity of the animals of western breeds. Inputs are not discussed and scarcity of resource is not even considered. The production system with its beautiful buildings and high mechanization, even automation, impresses them even more. It should not be surprising, therefore, that when it comes to the formulation of policy for requests for international or bilateral assistance, the developing coun­tries press for a delivery of the highest technologies and best genotypes. The donors seldom resist. In addition the international and national companies in developing countries have adopted very aggressive selling and export promotion techniques and they easily gain the ear of decision-makers in the developing countries on the question of importation of sophisticated technology and livestock. These companies are usually supported by export policies of the de­veloped countries and often use funds allocated for the development programme of developing countries. To this we should add export dumping, in developing countries, of hundreds of thousands of dairy heifers and cows from some highly developed countries as part of the policy of cutting dairy surpluses by reducing the number of dairy cows. We should not be shocked by this. Profit is the main motivation of the market economy, although, of course, there always were and still are those who call for prudence and conscience. This very seldom helps. There is a continuous flow of European livestock breeds and European animal production technology to developing countries. While it is true that the export bill is paid, for the most part, by developed countries, nonetheless the consequences burden the poorer countries.

European model of livestock production

Before we consider the usefulness of the different elements of the European Model of Animal Production for developing countries, it might be useful first to try to define it. We all know that even if Europe is limited, in this consideration, only to the EEC countries, there are still dozens of models and systems of livestock production. The rapidly growing standard of living in Europe brought increased demand for animal products with emphasis on their quality and uniformity. Industrialization and urbanization speeded up the land concentration and commer­cialization of livestock production. High profit orientation demanded high livestock efficiency and this was only possible with high inputs. From the technological point of view the European model of animal production is characterised by: 1. Intensive ruminant production based on efficient exploitation of grass/forage coupled with

high use of concentrates. 2. Increasing concentration of large numbers of animals with a high degree of mechanization

and even automation of labour, especially in pig and poultry production.

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3. Intensive animal selection based on mass performance recording, performance and progeny testing, and using modern population genetic methods.

In general, we might say that the European model is based on capital and grain intensive sys­tems of production, influenced by limited land area (high animal concentration) and expensive labour.

The high input system can naturally only survive with high animal performance and high concentration of production, and as we know both of these are common to the European model.

One important, indeed crucial factor, however, should be added here. The subsidization of European animal production, either directly or by trade barrier restrictions, defends the Euro­pean producers against cheaper production systems elsewhere.

Livestock development technologies

Let us now consider the main elements of livestock development technologies and examine the relevance of the European experience in the advancement of animal production in de­veloping countries. It is obvious that I can only attempt to do this in a very general way in view of the diversity of application and complexity of many of the technologies involved. I will deal here with genetic improvement, reproduction, nutrition and animal health.

Genetic improvement

There is no doubt that one of the reasons for the low productivity of the indigenous livestock in developing countries is its low genetic potential. Indeed in the past, due to unfavourable environmental conditions and the prevailing disease situation, natural selection dominated, and low productivity did not permit much if any selection for other aspects of performance. Genetic improvement of the productive traits of animals in developing countries came into consideration relatively late, practically on an important scale after the Second World War. Three basic methods of improvement of genetic potential of livestock are simultaneously taking place: selection within local indigenous breeds, cross-breeding and breed substitution.

Selection within indigenous breeds

Selection within indigenous breeds found some enthusiasts, mainly among specialists and scientists, who realised that local breeds lacking genetic production potential possessed many traits of extreme importance, such as adaptability to unfavourable local conditions, including the ability to utilise low quality feed-stuffs, resistance to some diseases, robustness, etc. This gave impetus to a number of attempts to improve local breeds in developing countries fol­lowing genetic strategies similar to those that had worked so well in Europe.

Not surprisingly, this approach did not bring meaningful results. The main reason was that the developing countries did and still do not have adequate infrastracture and means to organize on a sufficient scale reliable productivity recording. It is enough to say that until now it is difficult to pinpoint one developing country where production recording is so organized as to allow meaningful selection. I have in mind not only Africa but also Latin America probably with the exception of Cuba. For these reasons substantial international assistance, provided in the past to developing countries for the building of modem selection programmes to improve indigenous livestock breeds, has in general failed and proved not to be sustainable.

Crossbreeding

Given the apparent evidence of much higher levels of productivity in exotic breeds, it is not surprising that crossbreeding was considered as a major method for the rapid improvement of

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indigenous populations. It is fairly simple and relatively inexpensive to achieve and was adopted by virtually all developing countries. Equally as was to be expected, in most cases, the first cross appeared to produce more than the original material. However, the exotic was considered to be the only benefactor and backcrossing to the exotic followed the initial first cross.

Many experiments, and observations on methods of cross-breeding with different breeds used were carried out in developing countries (Cunningham & Syrstad, 1988). As might have been expected (and as should certainly have been directly investigated by proper backcrossing trials to both breeds) the F2 and subsequent generations generally proved less than satisfactory. Vaccaro (1989) in a review paper showed that overall herd productivity was lower in several different crossbreeding projects.

In general it was proved that intermediate level of genes coming from the temperate exotic breeds were superior to higher grades or imported breeds. It was shown, that for higher grades, more improved feeding and management is needed, but this is not always economically sound.

Breed substitution

Breed Substitution is another phenomenon taking place in developing countries. This is most advanced with poultry, followed by pigs and partly dairy cattle, whereas sheep, goats, buffalo and beef-draught cattle are almost not being touched by this process. Wherever the imported breeds were given proper feeding and management conditions, high productivity was achie­ved. The example of large dairy herds of Holstein-Friesian cows, large-scale European broiler and layer unit operations in different climatic zones can be quoted. However, when successful they are always accompanied by importation of feed-stuffs, equipment and foreign expertise. They are economically viable only when placed around big cities and market oriented towards the upper classes who can pay the higher prices or to provide subsidized food.

Whenever the production systems were not adequate to the requirements of the imported breeds the results were disastrous. Vaccaro (1989) after evaluating the performance of H-F cattle imported to the Latin American tropics, found that: about 14 percent of the females im­ported as calves or heifers failed to reach first calving or complete their first year, of every 100 female foetuses conceived by imported cows an average of 79 calves were born alive, with 44 surviving to the age of first calving. With a mean herd life of 2.6 calving, each imported dam produced an average 0.66 female replacements in her lifetime. For the H-F breed dams born in the tropics, the corresponding figures were slightly better resulting with one heifer repla­cement produced in the mean lifetime of 3.1 calvings per dam.

It is due to such cases that the replacement of breeds in the tropics and sub-tropics has received a lot of criticism in literature during recent years. It is fully justified as in most cases the decisions are taken without any economic consideration. On the contrary most of the dairy heifers recently imported into the tropics and sub-tropics have actually been dumped by the USA and EEC Countries due to the reduction of dairy cow populations. The results could easily have been envisaged. For example, in 1984-88 Venezuela imported 110,000 H-F heifers and cows with a government subsidy. The production of milk based on imported cows proved to be expensive, so under pressure from large producers, the Government raised the price of milk by 60 percent. This resulted in a 32 percent reduction of milk consumption per capita (Vaccaro, 1989).

New approach

What I have said above can be summed up by the following, that in the developing countries, selection within indigenous breeds has been too slow and ineffective, whereas unplanned cross-breeding is dangerous and breed replacement can be disastrous. While within breed im­provement as currently practised in developed countries is generally not practicable in the

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Table 2. Genetic screening ofAwassi ewes for milk yield in Turkey.

Nucleus Control Percentage

Lactation yield (kg) 310 + 7.7 223 + 9.3 +39% (range) (254-469) (97-360)

Lactation length (days) 206 + 1.7 187 + 4.4 +10% (range) (159-224) (95-222)

Maximum daily yield 2.7+0.1 2.1+0.1 +29% (range) (2.1^.2) (1.0-4.3)

developing world, the basic principles of genetic change remain the same. What then are we to do? In FAO we now believe that in developing countries we should return to the selection methods used in Europe in the last century, the selection methods used by Bakewell and the Colling Brothers, who developed the European breeds we have today. They screened the then unstructured populations for exceptional animals that met their ideas of improvement and we know they made substantial progress in a short time. Screening national sheep populations for exceptional animals was also carried in Ireland and Britain in the early sixties (Timon, 1964) and this led to the development of the very prolific Belclare Improver (Timon & Hanrahan, 1984) and Cambridge breeds (Hanrahan & Owen, 1985). Bichard & Siegel (1982) at the same time as Bolet & Legault (1982) developed selection methods for hyperprolificacy in pigs. So we have ample evidence that open nucleus breeding based on the genetic screening of large populations does work. Further to this we now understand more fully the genetic theory of open nucleus breeding based on the work of James (1977). The question is — can we apply these techniques in developing countries in the absence of formal recording schemes. We think so because we believe stockmen everywhere are capable of identifying outstanding animals. Timon (1988) developed the idea of screening large populations by using the observations of herdsmen in developing countries and then checking by simple measurements; subjective screening followed by selective validation.

Let me now briefly describe some relevant pilot projects. In 1986 FAO initiated a genetic screening programme to improve milk yield in Awassi sheep in a number of Near East Countries, viz., Turkey, Jordan and Syria. The selection was based on attempting to find ewes that were three standard deviations above the flock average in which they were milked. In absolute terms this meant finding individual ewes that milked twice the lactation average of their contemporaries in the flock. It meant that in practice 1,000-2,000 ewes had to be screened to find one such exceptional animal. Initial results are summarized in Table 2. Accepting that these results are preliminary, nevertheless the response to screening of nearly 40% is certainly very encouraging.

To fully exploit the genetic merit of the Nucleus flock we are now establishing an Awassi semen bank at one of the cooperating centres (Cukurova University, Turkey) and have plans to expand the propagation of the Nucleus germplasm.

Encouraged by the success of this first attempt to implement a Genetic Screening Open Nucleus Breeding Scheme (GS/ONBS) in developing countries, FAO is currently developing similar schemes for the improvement of the Djallonke sheep in West Africa and the genetic development of Tropical Hair Sheep in South East Asia. The application of genetic screening to buffalo breed improvement is also being planned, among others, using the city dairy herds (Jasiorowski, 1988a). We hope that the application of Open Nucleus Breeding schemes methodology in developing countries may open new possibilities for future livestock impro-

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vement programmes particularly when selected new technology can be harnessed to provide even greater gains.

Reproduction

It was mainly in the late sixties and seventies when much bilateral assistance was directed to the developing countries to build the artificial insemination infrastructure. In this case the European model was being transplanted almost exactly from highly developed countries to the developing countries. The scale of this programme can be reflected by the fact that there is probably not one developing country where AI has not been introduced, at least for dairy cattle.

The model implemented, as I said, reflected the European one. First the solid AI station was built with laboratories and concrete boxes for 20-50 bulls; deep freezing had to be an in­tegral part of the technology, and where liquid nitrogen was not available special Phillips equipment for its production was installed. Importation of pure-bred dairy breeds from Europe or North America was almost always part of such projects. In most cases, due to the lack of telephones, the farmers had to bring cows in heat to a certain place at a given time, where the inseminators, having travelled by motorbike, were inseminating.

This system worked at the beginning when funds and foreign assistance were available. In some countries, for example Kenya, good progress had been achieved. The problems started when the external support was withdrawn. First the liquid nitrogen plants broke4own. In many cases it was necessary to bring technicians from The Netherlands with spare parts. This part of the programme proved to be a total failure. Next came the cars and motorbikes for which there was frequently no petrol, no spare parts — not to mention their replacement. Last but not least, the bulls. After a few years of bad handling, undernourishment, exposure to climatic stress, skinny and often lame, it is hardly surprising that semen production was poor! Most important, however, was the economic unsustainability. Obviously farmers could not be expec­ted to pay the full cost of the service (including the inefficiency of the whole operation), and the governments were quickly forced to withdraw promised subsidies.

So it should not be any surprise that when one visits these AI centres now, for example in many African countries, he sees once beautiful centres partly abandoned and often in ruins, with the modern equipment covered by dust and scrapped cars and motorbikes lying around. Recently FAO, jointly with Uppsala University, Sweden, tried to analyse the sustainability of the African AI projects. It proved to be impossible due to the lack of reliable figures. Where the local staff still try to fight all these problems, a few old bulls are still exploited and I wish to briefly describe here one such AI station. Here are the figures: number of bulls 27, number of semen doses processed 1982:11,866; 1988: 5,962 doses (lack of liquid N); 1989: 26,874; number of people employed in the central station: 14 (5 with higher education), number of technicians in the field: 48. AI fees paid by farmers covers: 10 percent of the total cost of production. These figures describe one of the better AI stations in Africa, many are worse. In general if somebody is looking for a the classical example of the failure of transferring the European model to developing countries — AI provides many pointers.

Does it mean, however, that AI should not be used in developing countries? Such a conclusion would be totally wrong. When properly used, AI can, and even must, be a powerful tool in genetic improvement programmes in developing countries. As has been shown in many places, a much better solution has been to start small centres in the regions of intensive crossbreeding, or even to base AI on donated semen and produce crossbred bulls for natural service. A good example of AI properly fitted into the local situation, is AI for pigs in China, this was built according to their own 'indigenous' model. Specialised breeding units provide boars to the AI centres. These, centres, in turn, distribute fresh semen daily using local public transport (usually buses). The local inseminator meets the bus, collects his semen order and then does his rounds on a bicycle.

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The AI boom of the sixties and seventies in the aid programmes for developing countries is now over. The failures are fully recognised and the over-reaction of the donor countries is such that it is now extremely difficult to get any money even for the maintenance of those stations still working.

In the meantime, a new panacea for the animal production problems of developing countries appeared. This time it was embryo transfer. As with practically all new technologies, FAO has been approached, and even pressed, by most developing countries to make this available. In the case of embryo transfer, we realized from the beginning its limited practical usefulness for developing countries, but we were faced with a very aggressive promotion of the technology and embryos from a number of companies from developed countries. Again they had no diffi­culty in convincing the government of poor countries of the 'advantage' of importing know-how, equipment and especially embryos. Even if all this was paid for by developed countries, or in some instances by aid organizations, this money will have been badly spent and hence unavailable for more important needs.

FAO, while clear that embryo transfer is not a quick fix solution to all problems, is aware that it can play a useful role in certain circumstances. Initially, therefore, FAO has concentrated on the education and training of nationals from developing countries so that the technique is available within the country.

The multiple ovulation and embryo transfer (MOET) technique can be valuable to increase potential rates of genetic progress for meat type animals (Land & Hill, 1975; Steane et al., 1988) and to achieve similar results in dairy cattle (Nicholas & Smith, 1983). However, in the case of dairying the added benefit for developing countries is that the scheme does not require a massive investment either in recording (and accompanying infrastructure) or in achieving adequate levels of population literacy overnight. The effort to develop this new technology is likely to be cheaper and potentially more effective than the adoption of the traditional European large scale recording systems. Coupled with the genetic screening of the indigenous base populations it can optimise genetic advance in developing countries (Timon, 1989).

Feeding and nutrition

Looking at the animal feeding model in Europe we see two main features — abundance and high nutrient density. Indeed ad lib feeding with high grain, and protein rich feedstuffs in the diet is the rule in animal feeding regime in Europe for all species. As a result, up to 90 percent of available grain in some European countries is fed to livestock.

At first glance it would appear that the European systems of feeding are naturally out of the reach of the developing countries, except in certain cases for poultry and pigs, where intensive units are placed close to the big cities with good markets. In the vast majority of ca­ses, the situation in developing countries is quite the opposite to the European one — low quality and scarcity of feed is most common. So pastoralism and feeding of residues and by­products should be recognised as the main resources for animal nutrition in the developing countries.

To the surprise of many, however, the developing countries have increased the amount of grain fed to animals by 4.6 percent per annum, which is more than twice the increase taking place in developed countries. This may be partly due to the fact that during the last two decades, pig and poultry production growth rates in all developing regions have more than doubled those of ruminants. This may look alarming since over the last two decades cereal production in developing countries has grown by a mere 2.9 percent per year, the overall consumption, however, including feed use, has grown at the rate of 3.2 percent per year. It is projected that developing countries (without China) will increase the use of grain as feed from the present 100 million tons to 260 million tons in the year 2,000 (World Bank, 1989). Whatever we want to call this phenomenon it appears to be due to following the European model. In general, European animal feeding systems are simple. For ruminants it is pasture when and where

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available, plus corn silage, alfalfa hay and concentrates. For pigs and poultry it is standardised concentrates.

In tropical and sub-tropical developing countries this type of feeding is either impossible, due to climate and vegetation differences or it is too expensive. In those countries only rarely can feed be imported on a sound economic basis, so feeding must be adjusted to the resources available. On the small mixed cropAivestock farms, which form a large part of production systems in developing countries, there is usually a competition between food and cash crops and livestock for land. Feeding of livestock in such a production system is based mainly on marginal land grazing, crop residues and by-products. In most cases forage legumes can provide feed for dry periods. Recently a new approach, so-called 'Alley Farming', where leguminous trees and shrubs are grown as hedgerows, with the intervening ground cultivated for crops, has been developed. Pigs and poultry are normally free to scavenge around the household. In addition, development work to utilise local feeds has progressed. A good exam­ple is the use of sugar cane for pigs (Preston, 1987) — this work is now being developed and practised in several tropical countries. It provides relatively efficient and certainly more sus­tainable use of local resources. However, there is still little known about possible interactions of nonconventional feeds and also there is a need to develop better ways of getting such feeds into the trough. There is a need to provide information and help on how to supplement such feeds to overcome limiting nutrient problems and to use existing feed resources even more effectively.

Pastoralism, which usually occupies territories with 200-550 mm of rainfall, is popular in Africa, the Middle East, and parts of Asia. The productivity of rangeland in these regions is low and the investments in improving rangeland productivity rarely finds economic justifica­tion. The main problem of pastoralization in developing countries is communal land ownership which, together with individual ownership of livestock, must lead to overgrazing unless communal control is effective. Such systems did operate (e.g. the Hema System) but national boundaries and the reorganisation of local government have tended to destroy the traditional methods of control so essential to maximising output from such grazing lands.

Ranching is the system found in the developing countries of Latin America and some ter­ritories of Southern Africa. The main problem is seasonal fluctuation in pasture growth, which affects grass quantity and quality. The basic strategy for improvement is the introduction of improved species of grasses and legumes, and top dressing with phosphate fertilizers to impro­ve animal nutrition during critical periods. The World Bank invested a substantial amount of money in such ranch improvement strategies in Latin America, with little success. The attempts of the World Bank to introduce ranching systems into pastoral areas of Africa also failed — the lesson is one of attention to longterm sustainable development.

Looking into future possibilities of livestock feeding in developing countries, priority should probably be given to small ruminants and to methods of improving low quality rough­ages. Legumes and shrubs must play an important role as well as the diversification of the use of some highly productive plants like sugarcane and cassava (Preston, 1989), better use of crop residues and other by-product feed resources (Sansoucy & Mahadevans, 1983).

Animal health

In discussing animal production in developing countries, I cannot omit animal health.The problems of the developing countries related to animal health are well known. They have had to fight almost all possible diseases, as there is hardly one that has not been present. In general, international assistance in the field of animal health has been more successful than in the field of production. In particular it has helped to bring major infectious diseases under control. As examples I mention rinderpest and contagious bovine pleuropneumonia in Africa, heartwater in Eastern Africa and rift valley fever in Western Africa, African horse sickness in the Near East and African swine fever in Latin America (the last one was fully eliminated from this

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continent). Here again much more assistance should have be expected from developed countries. Building the buffer zones between developed and developing countries (Darian gap in Colombia and Thrace in Turkey) is very important and should get full support and invol­vement of all, but more important is that these and other buffer zones should be gradually moved southwest to include developing countries and to make them free of the most dangerous diseases. In the long run it would enable the developing countries to participate in the international trade of livestock and animal products, contributing to their overall development. However, even success bring problems; for example the eradiction or control of tse-tse flies allows increased stocking rates which, in many cases have caused overgrazing and serious de­terioration of the grazing area (Finelle, 1987). It is essential that planned increased feed avail­ability accompanies disease reduction otherwise improved health can result in poorer feed efficiency as a greater proportion of total feed is used for maintenance purposes.

In the case of animal health the problem of technology transfer from Europe is more straight­forward. The prevention or curing methods are usually the same, as well as the drugs to be used. The main problem that arises here, however, is again an economic one. The European drugs and preventive methods are frequently too expensive for developing countries when compared to the prices paid for animal products. For example, the use of trypanocidal drugs used for the survival of cattle in tse-tse infested areas cost around US $4 per head of cattle per year. The regular dipping of cattle against ticks in Africa costs up to US $15 per head and annum. These drugs and acaricides must be imported and paid for in hard currency. In the future greater attention should be given, in developing countries, to the treatment and control of the so called production diseases (parasites, nutrient deficiencies, etc.) which are less spectacular than infectious diseases but very limiting on production efficiency.

Until now veterinary services were organized in most developing countries on the basis of subsidised government services. In addition, veterinary training was given a 'kudos' which has resulted in an oversupply of veterinary officers in many countries and all within govern­ment service. Recently we observed a move towards the privatization of veterinary resources, which hopefully will put these activities on a sounder basis, and more adjusted to the local conditions.

Transfer of selected new technologies

As I have already stated low productivity of livestock in developing countries makes the local authorities very susceptible to the exotic innovations that are presented to them as stimulating to production and productivity. It is no surprise, therefore, that recently the use of anabolics for growth stimulation and Bovine somatrophin for lactation/growth has attracted the ear of the governments in the Third World. The fact that these agents are not permitted, in at least a majority of the developed countries, and that the developing countries have no possibility to ensure the monitoring or safe use (residues levels) is not taken into account during energetic sales promotions. As market possibilities in developed countries decrease so more pressure is put on the markets in poor countries; selling banned pesticides to the developing countries is a good illustration of this situation.

We have had, on recent occasions, to deal with many developing countries who have sought FAO advice on the use of BST. It has taken a lot of arguing and energy on our part to convince the authorities that the use of BST is not a remedy for their undernourished cows. The fact that positive results have been obtained under the ad-lib feeding conditions, and that this hormone does not increase the efficiency of feed utilization for milk, was hardly an argument to them. We do not have enough data to judge, but I am sure that many international companies have already established a market for anabolics agents and BST at least in some developing countries. It will strongly increase when these drugs are released for practical use in developed countries.

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Clearly many technologies have a place in the developing world but this place must be carefully judged and properly planned. For example, the development of new, more stable and efficient vaccines should clearly benefit the developing countries if problems of infrastructure are overcome. The biotechnical manipulation of feeds (or of rumen efficiency) will undoubtedly be of value to countries where indigestible fibre is all too common.

The crucial factor in the transfer of new technologies is the need to ensure that its role and potential are clearly understood and proper planning for its use and for the consequences of such use is made, before the technique develops expectation and an aura sometimes more applicable to a pop star.

Research

Much hope is attached to research which should help developing countries cope with their problems of animal production development. Unfortunately, in general, the research centres and universities working on animal production problems in developing countries are rather weak and ineffective. It is true that many young and able scientists from developing countries are offered the opportunity to study and graduate at the world's best universities, but very seldom do they bring back to their home countries the ability to analyse the home situation and select the most important research topics. Even if they do, they often cannot get sufficient funds and infrastructure to support their efforts. The universities and research centres in de­veloped countries are, in general, not interested in the research programmes which would deal with the problems of developing countries. The most that the best of them ca^ do is to offer the students from developing countries PhD topics related to their home country problems.

During recent years this situation has got worse. Nowadays more and more serious pio­neering, fully innovative research work is being undertaken in huge, private, multinational companies. The privatization and commercialization process observed in developed countries has accelerated their progress, but on the other hand it makes the transfer of achievements to developing countries much more difficult. Market oriented research in such important animal production fields, for example genetic engineering, the pharmaceutic and feed industries and biotechnology, excludes, for obvious reasons, programmes direcdy relevant to the developing countries (Jasiorowski, 1988b). Who in developed countries works seriously, and on a sufficient scale, for example, on a new trypanosomiasis drug, or a more specific insecticide against tse-tse fly? Why does the problem of genetic modification of rumen microflora, for better utilization of high fibre and high lignin feedstuffs, not get more attention? Why is the physiology of undernourished animals and their supplementation not studied by research establishments? Many more examples could be given.

To be objective however I must state that the above mentioned problems have been recog­nised by some people. It is due to their efforts that the CGI AR system of international institutes working for developing countries, has been established. In our field there are two such insti­tutes, the International Livestock Centre for Africa (ILCA, Ethiopia), and the International Laboratory for Research on Animal Diseases (ILRAD, Kenya), but they can only fill the gap on a very limited scale.

I sincerely believe that much more should be done to strengthen national universities and research centres in developing countries; and the research institutes and universities in the de­veloped world should include, more often, in their programmes the problems of developing countries. If we sincerely believe in the slogan that the world's resources should be the global responsibility of the whole of humanity, then we have to agree that 75 percent of the world's livestock resources should not be left outside of scientific interest

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Conclusions

Let me now come back to the question in the tide of this paper. It would seem clear that the European model of animal production has been determined mainly by socio-politico-economic circumstances. Environmental, biological and even technical aspects have played a secondary role.

If I am right, it is clear that when discussing the usefulness to developing countries of the European model of animal production, we must look first of all into the similarity of the socio-politico-economic factors in these two parts of the world. Such a suggestion may appear ridi­culous, because we all know very well that such similarities are rare or non-existent. On the contrary, all the main social, political and economic factors which influence animal production systems in the developing and European countries are different, sometimes even opposed to each other. We have every reason to believe that these differences may even increase in the future. If we accept the above mentioned criteria, there is only one answer to the question posed in the title of my paper. The socio-economic and political circumstances are so different in developing countries that they cannot adopt directly the European models of animal pro­duction. Life, however, is more complicated, and can very seldom be considered in such categoric black or white terms. Often, as here, the situation is grey. For example, recently, an excellent analysis of animal production systems in mediterranean region was published by Boyazoglu & Flamant (1990). It shows clearly that those sheep production systems, including dairy sheep can have application in other dry subtropic regions.

Developing countries find themselves in too dramatic a situation to be able to reject outright the European experiences of animal production and go their own way, and gradually improve their indigenous systems of production which previously over the centuries had proved to be sustainable. The rapid growth in human population does not permit such a slow process. In addition, and as I mentioned earlier, this process of westernization of animal production sys­tems in developing countries is strengthened by a strong export promotion from developed countries. This process can be seen clearly in the case of the introduction of exotic genotypes. As in commerical poultry and pig production, the European breeds either replace the local breed or are used for intensive upgrading. This same process is taking place with dairy cattle.This process will probably continue but it must be accompanied, to a larger extent than now, by the improvement of feeding and management. Nevertheless it will lead to the reduction of a number of breeds and genetic variation. It calls for the establishment of a strong balanced programme for animal genetic resource utilisation (Hodges, 1990). This can, however, only be done in developing countries with the financial support of the developed countries.

Finally I would address a very strong plea to the European animal scientists in their future support to livestock production in the developing countries. 1. Yes, much of your technology can be relevant but you must tailor it and simplify it to meet

the needs of developing countries. 2. Yes, your University curricula cover well the basic sciences that underpin developing

country livestock problems but I would encourage you to develop more post graduate de­gree courses and thesis work based directly on problems relating to the developing coun­tries. In this regard I would like to see more twinning arrangements between European and developing country universities and research institutes, involving exchange of staff (saba-ticals) and direct identification and supervision of thesis work carried out in the post graduates home country. FAO and other aid agencies strongly support such links and can help with some finance.

3. Finally as regards the impact of animal production on the environment (overgrazing or the methane problem for example) it is imperative that all of us, European and developing country alike, work in close partnership to guide the global development of animal production down an environmental friendly path.

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References

Bichard, M. & Seidel, CM., 1982. Selection for Reproductive Performance in Material lines of Pigs. Proc. 2nd Wld. Cong, on Gen. Appl. Anim. Prod. Madrid. Vol. 8:565-569.

Bolet, G. & Legault, C, 1982. New Aspects of Genetic Improvement of Prolificacy in Pigs. Perc. 2 Wld. Cong. Gen. Appl. Anim. Prod., Madrid. Vol. 5:548-567.

Boyazoglu, J. & Flamant, I.C., 1990. Mediterranean systems of animal production. In: The world of pastoralism. Guilford publications, New York.

Brumby, P., 1989. Livestock and food production; Strategic Issues for IFAD, Report No. 0163, 1989.

Cunningham, E.P. & Syrstad, O., 1987. Crossbreeding bos indicus and bos taurus for milk production in the tropics. FAO Animal Prod, and Health Paper No. 68.

Finelle, P., 1987. The African animal Trypanosomiasis: economic implications. The FAO pro­gramme of action. La Medicina Tropicale nella Cooperazione alio Sviluppo. Vol. 3, No. 1, 1987.

Hodges, J., 1990. The global organisation of animal genetic resources. Proc. 4th World Congress on Genetics appplied to Animal Production, Edinburgh, July 1990 (In Press).

James, J.W., 1977. Open nucleus breeding systems. Anim. Prod. 24:287-305. Jasiorowski, H.A., 1973. Twenty years with no progress. World Animal Review, Vol. 1., 1973. Jasiorowski, HA., 1988ba. Perspectives and prospectives of buffalo breeding for milk and

Meat Production in the World. Proceedings of the 2nd WorldBuffalo Congress, Vol. 2, Part 1, New Delhi, India, 1988.

Jasiorowski, H.A., 1988b. New scientific achievements and livestock development assistance to developing countries. Real Academia de Ciencias Veterinarias, Madrid, 1988.

Land, R£. & Hill, W.G., 1975. The possible use of superovulation and embryo transfer in cattle to increase response to selection. Anim. Prod. 21:1-12.

Nicholas, F.W. & Smith, C, 1983. Increased rates of genetic change in dairy cattle by embryo transfer and splitting. Anim. Prod. 36:341-353.

Preston, 1987. Pigs and poultry in the tropics. Utilization of local feed resources. CTA, Wageningen. The Netherlands, pp. 25.

Preston, 1989. Sugarcane as animal feed. An overview in sugarcane as feed. FAO Animal Pro­duction Paper No. 72 (Sansoucy et al., Editors), FAO, Rome, 1989. pp. 61-71.

Sansoucy, R. & Mahadevan, P., 1983. Potential Lignocellulose resources and their utilization by ruminants in tropical regions in nuclear techniques for assessing and improving ruminant feeds. I.A.E.A., Vienna, 1983. pp. 125-135.

Steane, E.E., Simon, G. & Guy, D.R., 1988. The use of embryo transfer in terminal sire sheep breeding schemes. Proc. 3rd Wld. Cong, on Sheep and Cattle Breeding, Paris. Vol. 1. 211-3.

Timon, V.M., 1968. Selection of high fertility sheep. AFT Annual Research Report, 1984. Timon, V.M. & Hanrahan, J.P., 1984. Use of selection and crossbreeding in the genetic impro­

vement of reproductive efficiency in sheep. International Sheep Symposium, Sofia, 1984. Timon, V.M. & Baber, R.P., 1988. Genetic improvement of sheep and goats in the humid tropics

of west Africa. FAO Anim. Prod, and Health Paper No. 70:14-29 Timon, V.M., 1989. A protocol for boosting genetic gain in genetic screening/open nucleus

breeding using MOET. FAO Mimeo, Turkey, 1989. Vaccaro, L„ 1989a. Multipurpose use of livestock. Paper presented at CTA meeting on "Inte­

gration of Livestock with Crops" in Mauritius. Vaccaro, L., 1989b. Survival of European dairy breeds and their crosses with Zebus in the tro­

pics. In press.

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Synthese de la 2ème session

J. Coleou

Département des Sciences Animales, Institut National Agronomique, Paris-Grignon, 16, rue Claude Bernard, 75231 Paris, France

II est extrêmement difficile et prétentieux de tenter de synthétiser les apports très importants et déjà denses des cinq conférenciers intervenus dans cette Session intitulée "Les défis et interrogations du futur". H est cependant nécessaire de dégager les enseignements principaux et les axes d'actions prioritaires auxquels nous devons nous attaquer pour que les spécialistes des Sciences Animales contribuent efficacement à préparer l'avènement du 3ème millénaire. Mon propos final s'inscrira dans cet objectif: "Un bilan pour guider nos actions futures".

Il est évident qu'un Symposium comme celui-ci ne pouvait limiter ses réflexions prospec­tives au seul espace européen, même s'il était organisé en Europe et par la Fédération Euro­péenne de Zootechnie. Ma synthèse se placera sur les deux champs de la géographie et du niveau de développement abordés dans le Symposium: • le Nord et le Sud; • WI et Win (nomenclature du Prof. Pirchner); /

• les pays développés et les pays en développement.

Problèmes et perspectives au Nord

Les attentes du consommateur et l'image des produits animaux

En Europe et dans la majorité du monde industrialisé, une offre abondante de produits et une sensibilité accrue des populations à la perception de l'évolution des techniques de production nous imposent collectivement d'être: • à l'écoute des consommateurs; • à la recherche de solutions appropriées pour satisfaire leurs attentes, dans des conditions

économiquement viables, pour le producteur comme pour le consommateur; • en situation d'améliorer l'information des consommateurs sur les caractéristiques de nos

produits. Plusieurs rapports ont souligné les composantes d'une image negative qui se développe dans nos pays à rencontre des produits animaux (excès de gras, excès de cholestérol, systèmes industriels, concentrations animales, emplois d'additifs...).

Nous ne devons pas subir passivement cette pression psychologique, aux conséquences économiques considérables, induite et entretenue principalement par les médias • il y a des possibilités de réponse par la Zootechnie: elles ont été déjà et elles doivent

continuer à être mises en oeuvre à chaque fois que possible, comme l'a souligné et illustré le Professeur Pirchner à travers les actions par voie génétique,

• nous devons participer activement à une meilleure information du public, sur la sécurité d'emploi et l'innocuité des substances utilisées comme facteurs d'amélioration de l'effi­cience zootechnique aux doses et dans les conditions où elles sont utilisées.

• nous devons développer, avec nos collègues spécialistes de la nutrition et de la santé humaines, des études épidémiologiques pour identifier objectivement les risques imputés à la consommation de produits animaux en général, de graisses animales en particulier.

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Il serait dangereux de laisser se développer, à travers des approches uniquement compartimen­tées, l'image d'accroissement du risque d'accidents de santé, cardio-vasculaires notamment, en relation avec l'augmentation de la consommation de produits animaux. Des approches plus complexes, prenant en compte l'ensemble du système alimentaire, ont montré, en effet, que la relation entre fréquence des accidents cardio-vasculaires et teneur du régime en graisses ani­males n'était pas, dans tous les cas, aussi nette et aussi établie que cela est actuellement généra­lement admis: d'autres facteurs, en cours d'étude, permettraient d'atténuer les risques et de comprendre ce que des épidémiologistes ont appelé, pour le cas de la France, le 'paradoxe français'.

La responsabilité des éleveurs et des zootechniciens dans la gestion de l'ecosysteme

Il est désormais clairement établi que l'évolution de nos systèmes de production peut compromettre, de façon grave et durable, voire irréversible, plusieurs composantes de notre patrimoine 'terre', 'espace'.

Le risque le plus important de déséquilibre est induit par la concentration très forte des productions animales sur certaines zones à faibles disponibilités en surface agricole où le transfert d'aliments pour animaux dans des unités de production horssol rend difficile ou impossible le recyclage agronomique, dans des conditions normales, des déjections produites. Plusieurs régions d'Europe sont exposées à ce risque, mais c'est le système zootechnique néer­landais qui connaît déjà une situation grave en matière de gestion de son écosystème et des conséquences, immédiates et à terme, sur l'approvisionnement du pays en eau consommable et sur les compositions de son sol, au moins dans les régions à forte concentration porcine.

Si cet aspect n'a pas été approfondi durant le Symposium, des spécialistes néerlandais de Science du Sol considèrent que, dans le Sud des Pays-Bas, où s'est surtout développée la production porcine: • la bataille de l'azote est déjà perdue avec des effets négatifs, sur plusieurs décennies, des

concentrations de nitrates dans le sol; • celle de l'accumulation du phosphore peut encore être gagnée, mais à la condition de se

mobiliser rapidement et très énergiquement; • la concentration de certains métaux lourds comme le Cadmium est déjà très préoccupante. Quelques indicateurs schématiques illustrent bien le niveau moyen d'intensification agrono­mique et zootechnique néerlandais. Sur 1 hectare de surface agricole utile, à l'échelle de l'ensemble du pays: • les techniques agronomiques mettent en oeuvre une fertilisation azotée qui correspond à 4

fois la quantité utilisée en France ou en moyenne de l'ensemble EUR 12; • les techniques d'élevage font appel à l'importation et à la transformation par les animaux

de 8 à 8.5 tonnes d'aliments composés, soit l'équivalent de la production de la biomasse en aliments concentrés (grains + protéagineux) d'un 2è hectare placé au dessus du 1er et dont l'hectare de base doit recycler tous les effluents.

Inutile de souligner que, dans les secteurs du Nord-Brabant où la densité porcine est la plus forte, c'est une vraie batterie de 3 ou 4 hectares, c'est-à-dire de 3 ou 4 étages au-dessus de 1' hectare basai, qui représente l'image du niveau d'intensification et de risque.

Il n'entre, bien entendu, à travers cet exemple, aucune idée de polémique ni d'accusation, mais seulement une base de réflexion stratégique collective, à laquelle nous devons tous ac­corder une attention soutenue, car d'autres zones européennes peuvent également courir ce risque.

Un deuxième risque se profile en matière de gestion de l'écosystème: celui du recul des herbivores dans l'exploitation et l'entretien des espaces et des paysages.

Tout un ensemble de facteurs (politiques, économiques, fiscaux, structurels...) font que la mobilisation des principaux herbivores (ruminants, équidés) pour la mise en valeur des surfaces agricoles et pastorales des nombreuses zones de montagnes, de collines, de régions

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fragiles de plusieurs pays européens apparaît de plus en plus difficile: comme l'a souligné Claude Beranger, nous avons à inventer et à gérer des systèmes pastoraux extensifs à l'euro­péenne, sans pouvoir transposer ou nous inspirer de modèles d'élevage extensif développés dans d'autres zones du monde. A défaut, nous verrons s'accroître: • le risque d'extension des friches, avec un préjudice sur la qualité des paysages et l'occupa­

tion des espaces; • une menace croissante, surtout au Sud de l'Europe, d'agression des incendies sur les massifs

boisés. Ce problème se pose avec une certaine acuité dans plusieurs pays de la C.E.E. • du fait du recul du cheptel bovin laitier, induit par les quotas, et du non remplacement, à

effectif total constant, par des bovins allaitants; • du fait de la situation globale du marché ovin: l'Europe des Douze a un déficit en viande

de mouton et d'agneau qui correspond à la production annuelle de 12 millions d'agneaux; • du fait de la fonte du cheptel d'équidés lourds. Dans cette gestion rationnelle de notre écosystème le développement de systèmes de produc­tions animales, associant deux ou plusieurs espèces, mériterait d'être réexaminé, en réaction à l'évolution tendancielle majeure, enregistrée au cours des dernières décennies, vers des systèmes monospécifiques.

Les stratégies génétiques et le maintien d'une variabilité suffisante dans nos différentes espèces

Pas inquiétant à court ou moyen terme, comme le souligne le Professeur Pirchner le problème mérite de retenir toute notre attention pour le plus long terme, • la disparition ou le recul brutal d'un très grand nombre de nos races locales ou régionales; • l'évolution de la sélection à partir d'un nombre très limité de souches.

Une attention plus grande à accorder à une somme d'indicateurs d'efficience zootechnique

Tous les zootechniciens travaillent, chacun dans sa spécialité, à l'amélioration de l'efficience des animaux en tant que transformateurs des aliments en produits à plus haute valeur biolo­gique et marchande.

Pour survivre et supporter la concurrence des autres productions, animales ou végétales, l'effort d'amélioration de la productivité doit être soutenu dans tous les systèmes animaux. Le Professeur Alderman a présenté six indicateurs d'efficience. Le pilotage de nos actions mérite­rait que davantage d'études et de recherches soient consacrés à ce thème de l'efficience.

Repenser et enrichir nos stratégies d'enseignement et de recherche

Le futur de nos productions dépendra très fortement de la capacité d'ouverture des enseignants et des chercheurs et de l'aide éclairée qu'ils apporteront à la formation et au perfectionnement des acteurs des différentes filières animales.

Gérer en manager le changement avec clairvoyance et anticipation: le sixième sens, ainsi que l'appellent nos collègues italiens les Professeurs Matassino, Zucchi et Berardino, ne sera pas de trop pour cela.

Or nous sommes menacés par la tentation de céder au pouvoir scientifique des techniques avancées de recherche, souvent réductionnistes par nécessité, mais qui peuvent nous faire dé­boucher sur l'incommunication par cloisonnement excessif.

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Problèmes et perspectives au sud, relations Nord-Sud et Sud-Nord

Des disponibilités en protéines animales faibles et en faible croissance: un enjeu considérable

Beaucoup de pays du Sud présentent, depuis trois décennies, un bilan compris entre 5 et 10 g. de protéine animale par habitant et par jour, contre 24 g. en moyenne mondiale, près de 60 g. pour l'ensemble de l'Europe, 75 g. pour la France ou la Nouvelle-Zélande. La progression y est faible ou nulle du fait de la forte croissance démographique.

C'est un défi considérable qui se trouve posé à tous les zootechniciens du monde: éviter que ne se creuse encore plus cet écart.

Des ressources en aliments énergétiques et azotés insuffisantes pour l'intensification animale

Comme l'a souligné le Professeur Jasiorowski, les pays en développement se tournent de plus en plus vers les productions avicoles et porcines pour tenter d'améliorer rapidement leur bilan protéique. Mais ils se heurtent à la faiblesse de leurs ressources en céréales et en matières riches en protéines: • le bilan céréalier 1989 fait apparaître, pour l'ensemble des pays en développement, une

ressource de 250 kg par habitant, contre 710 kg pour les pays développés. Certaines zones, comme l'Afrique, détiennent 145 kg/Hab./an, c'est-à-dire à peu près la con­sommation annuelle directe par habitant. Il ne reste donc rien de disponible pour 1'ahmentation animale. Rien d'étonnant en conséquence à ce que ces pays aient vu leurs importations en céréales passer, en 20 ans, de 20 à 150 millions de tonnes par an. • le bilan des ressources mondiales en matières riches en protéine (tourteaux, farines

animales...) assure une offre par habitant de 20 kg par an. Mais la demande moyenne, dans les pays développés, à travers les systèmes animaux actuellement en place, se situe à 80 kg aux U.S.A., à 100 kg dans l'Europe des Douze, avec plus de 300 kg aux Pays-Bas et 400 kg au Danemark. Il est évident que la faible ressource en ce groupe de produits dans les pays en développement vient aggraver la situation énergétique précédente.

Des innovations obligatoires pour renforcer les apports de la biomasse primaire

Avant toute autre action, les zootechniciens devraient consacrer beaucoup d'efforts: • à identifier de nouvelles espèces, adaptées aux différents milieux, et appropriées pour

améliorer les bilans énergétiques et azotés pour les animaux; • à expérimenter et à promouvoir ces espèces, au plan de la production et au plan de

l'utilisation. Deux groupes d'espèces ont un rôle stratégique à tenir en zone tropicale, dans cette perspective: • les racines et tubercules, en zone tropicale humide, dont le manioc, déjà entré, au cours des

dernières décennies, sur le marché international; • les arbres de légumineuses, en tant que producteurs de gousse^ et donc d'aliments concen­

trés, auxquels peu d'efforts scientifiques ont été consacrés. Pourtant, leur impact en zones arides ou semiarides pourrait être étonnant et révolutionnaire par rapport à l'ampleur et à la complexité des problèmes posés.

Des stratégies génétiques raisonnées et raisonnables

Le Professeur Jasiorowski a très bien analysé les différentes stratégies génétiques. Il convient d'éviter l'illusion et le mirage des transferts brutaux d'animaux à hautes potentialités. D y a,

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en revanche, des schémas astucieux de croisement à mettre en oeuvre, surtout dans les zones à risque, comme c'est le cas des régions d'Afrique à trypanosomose bovine.

De nouvelles démarches à inventer dans les relations entre le Nord et le Sud pour, à la fois:

• animer le développement des productions animales; • former les hommes sur la base des réalités du pays; • chercher les composantes de systèmes de développement appropriés. Nos relations entre le Nord et le Sud doivent être radicalement changées dans leurs objectifs et dans leurs méthodes, en faisant acquérir, aux futurs cadres, une compétence par rapport aux problèmes majeurs et à la situation réelle de leur pays.

Une dynamique nouvelle devrait associer non seulement des échanges de savoir et de savoirfaire, mais aussi des échanges de produits, et l'intervention combinée d'experts scien­tifiques ou technologiques et de managers d'entreprises de nos filières animales.

Des défis de taille, une mobilisation de nos énergies, et de nos capacités d'innovation d'innovation

Nous ne pouvons pas nous replier frileusement dans nos pays développés: le sort de 75 % et bientôt plus de 80 % de la population de l'humanité se jouera sur ce champ des pays en dévelop­pement.

En conclusion générale, nous aurons surtout, au cours des prochaines décennies

• à gérer, au Nord, l'image de nos produits, nos espaces de vie et de production, notre patri­moine génétique, nos strategies de formation et de production d'innovation, pour assurer aux éleveurs et aux autres acteurs des filières de produits animaux, insuffisamment pris en compte dans ce symposium, une amélioration permanente de l'efficience zootechnique, et aux consommateurs la sécurité d'un approvisionnement en produits sains et de qualité.

• à mobiliser, pour le Sud, toute notre capacité de créativité, car le problème est immense et les réponses ne se trouvent pas toutes faites au nord.

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