breed conservation - discover

D. PHILLIP SPONENBERG, DVM, PHD

VIRGINIA-MARYLAND REGIONALCOLLEGE OF VETERINARY MEDICINE

VIRGINIA TECH, BLACKSBURG, VA

AND - THE AMERICAN LIVESTOCKBREEDS CONSERVANCY

steps in conservation

ALBC uses these steps in conservationdiscover (encounter and define)secure the populationsustain for the long term

all three steps are needed to assure success in the survival of breeds

discover

The first step is to discover these rare breeds and populations

the USA has a good informal network with an interest in the conservation of these resources

discover

this network usually indicates the existence of a population that is a candidate for conservation

usually this network commits “errors of inclusion” rather than “errors of exclusion” which helps to alert conservationists

misses relatively few breeds from consideration

always better to commit “errors of inclusion” because this indicates that the network is unlikely to ignore a population that truly merits conservation

discover

part of the “discover” step is defining breeds and populations

define

define

ALBC uses this definition of “breed”a group of animals with a phenotype that is distinct and recognizable, and that produces this type after being mated within the population

this definition is based in genetics, and establishes the breeds as genetic resources

implies a certain level of genetic uniformity and predictability

this definition of breeds ignores populations with high levels of variability, even if some of these do have cultural importance

goal is the conservation of genetic resources that can be predictable as they serve agriculture

define

classes of breeds

local – landrace – adapted- rustic

standardized

industrial

feral

classes of breeds

each class of breeds needs its own appropriate strategy for effective conservation

industrial

little or nothing possible for their conservationimpossible to duplicate the physical and

selection environment in which these animals live

high risk that some will go extinct

standardized breeds have breed associations for their breeders

standardized breeds are usually well definedconservation of these is easier than the othersimportant to maintain a high level of genetic

variation

standardized breed

few are important to conserveisolated for long times with distinct foundation

and physical type

feral breeds

landrace

usually well adapted

usually poor documentation (history, production)

poor recognition as a true breed in most places

productive potential is poorly documented

ome do have high production potential and are important to conserve and develop

ost are adapted and resistant

landrace

landrace

they do need to be “genetic resources” in the strict sense

need a level of genetic variation that does not prevent prediction of performance

landrace

these need to be defined carefullyimportant to decide which animals to include and

which to excludein many cases need to rescue a breed or a

bloodline without losing characteristics

landrace

need to develop strategies for long term maintenance

landrace

three steps for effective conservation

Discover/ encounter/ definesecuresustain

Final success depends on all three steps

for landraces it is necessary to decide if the population is truly a breed in the genetic sense

“breed” in this sense is a group of animals that are similar by origin and type, and that reproduce that type after mating within the group

discover

To decide if a population is a breed depends on investigations

phenotype (measured or visual inspection)historygenetic data (bloodtypes, DNA fingerprints)

landrace

investigation - history

ideal is long term isolation from other breeds

isolation comes from geography or owner practices

history

some cases will have high levels of isolation

many cases will have doubtful histories, or even more than one version of history

the history and the external phenotype usually agree

investigation - phenotype

in the US few people experienced in zootechnology

rare to measure animals to define breeds

measurements are always more accurate but are not possible in all cases

feral animals, or very extensive systems, present challenges to phenotypic evaluation – especially if measurements are needed

phenotype

look at the animals and compare them to other breeds in the area, looking for evidence of crossbreeding or mixtures with other breeds

this method, even though not exact, works very well in practice

history and phenotype usually agree

most populations either have the uniformity expected of a true breed, or are very variable from crossbreeding

steps one and two

traits such as color or presence/absence of horns are usually not very important

landraces usually vary more in these traits than do standardized or industrial breeds

this variation doesn’t prevent use of these breeds

conservation should include this variability

steps one and two

step three

genetic investigations are more expensive than those for history or phenotype

usually genetic investigations after the other twoafter eliminate populations obviously crossbredinclude only those that are more uniform

genetic data

genetic data are usually for relative frequencies of alleles

can be analyzed different ways to reveal relationships of populations

branching tree of breed relationships

points out breed groups

this type of “tree”also reveals the relative groupings aswell as the distance ofeach population from the others

complicated, butindicates individualanimals, and howdifferent they are if the population is split twoways, three, four, or fivereveals fundamentalpoints of division

genetic results provide background for deciding appropriate strategies for conservation

can reveal a mixed or uniform population

can indicate animals to include or exclude

step three

DNA results can indicate relationships between breeds, and which are most distinct or distant from others

step three

some individual animals are very important for genetic variation for the future of the breed

step three

Pineywoods cattle

from southeast USAadapted to a humid subtropical environmentiberian origin

Pineywoods

herds isolated from one another for a centuryone breed or many?all of the cattle are more like one another than

any other breedall of the herds have low numbers.logical to include them all in a single breed to

assure their effective conservation

Pineywoods

BOUNDS

SEAL

GARNER

LADNERHICKMAN

DIAMOND

DEDEAUX

CONWAY

O’NEAL

PALMER

VICE

AGRICOLA

BEACH

BROADUS

BAYLIS

CARTER

CLARK

BARNES

ROBINSON

GRIFFEN

HOLT

POPPLE

ALBANY

EZELL

KNAPP

bloodlines

Pineywoods

each breeder thinks his cattle the most pure of all

need to replace that attitude with more inclusion

Pineywoods

philosophy that works for this breed is to include all of the typical cattle from this region under a single registry and association

cattle are inspected to exclude the herds that have evidence of influence from zebu, Devon, Angus, or Hereford

Pineywoods

these cattle vary more than standardized breedsimportant to include this variation

dwarves and polled (hornless) cattle

Pineywoods

another breed is closely related: Florida Crackertwo breeds were separated due to decisions

based on regionalism of the breedersDNA results indicate these two breeds have been

separated for more than a centurysome distinctions have arisen

Pineywoods

effective to separate the two breeds to conserve

Pineywoods

in the beginning the association encountered resistance from traditional breeders

would not register cattlechange to free registrations worked to increase

the numbers of breeders registering cattle

Colonial Spanish Horses

similar to the Pineywoods cattle breedmany herdseach isolated for centuries

one breed or many?

Strains of the breed

some herds have fewer than 30 horsesimpossible to maintain these in isolation for the

long term, without inbreeding

Colonial Spanish Horses

Colonial Spanish Horses

total population is likely under 3,000 horses

all of these horses are very similar to one another

very distinct from other horses in the USA

logical to group them together for conservation

Colonial Spanish Horses

equinos c

Colonial Spanish Horses

Co

goal is to save the various bloodlines in several herds

also to blend these into a composite mixture