Effects of Creep Diet Complexity on Individual Consumption ... · Mixing eaters with non-eaters...

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Nursery Pig Nutrition and Management

Effects of Creep Diet Complexity on Individual Consumption Characteristics and Growth Performance of Neonatal and Weanling Pigs1

R.C.Sulabo,M.D.Tokach,J.R.Bergstrom,J.M.DeRouchey,R.D.Goodband,S.S.Dritz2,andJ.L.Nelssen

SummaryInExp.1,96sows(PICC29)andtheirlitterswereusedtodeterminetheeffectsofcreepdietcomplexityonpreweaningperformanceandtheproportionofpigletsconsumingcreepfeed.Theexperimentaltreatmentswere:(1)nocreepfeed(n=26),(2)simplecreepdiet(n=26),and(3)complexcreepdiet(n=44).Pigsfedthecomplexcreepdiethadgreater(P <0.03)ADGandtendedtohavegreater(P <0.06)totalgainthanpigsfedthesimplecreepdiet,withnocreeppigsintermediate.Littersfedthecomplexcreepdietconsumedtwicethetotal(2.73vs.1.37lb;P <0.0006)anddaily(0.91vs.0.45lb;P <0.0006)creepfeedintakeoflittersfedthesimplecreepdiet.Thehigh-complexitycreepdietimproved(P <0.0001)theproportionofeatersfrom28%to68%.Agreater(P <0.10)proportionofeaterswerenursinginthemiddleandposteriorteats(57%and52%,respectively)thanintheanteriorteats(38%).InExp.2,675pigsfromExp.1(initialBW14.1lband21.2±0.2d)wereusedtodeterminewhethersocialfacilitationoccursbetweeneatersandnon-eatersincommercialnurserygroups.Thetreatmentswere:non-eatergroup(pigsthatwerenotprovidedanycreepfeedornon-eatersofcreepfeed),eatergroup(pigsthatpositivelyconsumedcreepfeed),andmixgroup(pigsthatwere51%non-eatersand49%eaters).Eachtreatmenthad25pigsperpenand9replications(pens).Intheinitial3dpostweaning,eatershadgreater(P <0.01)ADGand(P <0.002)ADFIthannon-eaters,withthemixgroupbeingintermediate.OverallADGoftheeatergroupwas6.2%higher(P <0.05)thanthatofthenon-eatergroup.Forsocialfacilitationtooccur,weightgainsofnon-eatersinthemixpensshouldbeeither(1)closertotheweightgainsofeatersinthemixpenor(2)greaterthantheweightgainsofthenon-eatergroup.Resultsshowedthatnon-eaterswithinthemixpensfailedbothcriteria.Inconclusion,thehigh-complexitycreepdietimprovedpreweaningADG,littercreepfeedintake,andtheproportionofeaters.Eatershadimprovedpostweaningfeedintake,dailygains,andweightuniformityandreducedpostweaninglag.Mixingeaterswithnon-eaterswithinpensinlargecommer-cialgroupsdidnotstimulatefeedintakeanddailygainsofnon-eaters,whichindicatesthatsocialfacilitationdidnotoccur.

Keywords:behavior,creepfeeding,dietcomplexity

IntroductionMaximizingpostweaningpigperformanceisessentialinimprovinglifetimegrowthefficiencyandproductivity.However,weaningisoftencharacterizedbyaperiodoflowfeedintakecausedbyphysical,physiological,andbehavioralchallengesthatmayresultinagrowthcheckandaffectpostweaninggrowthrates.Thus,improvingfeedintake1AppreciationisexpressedtoKeeseckerAgri-Business,Inc.fortheuseofpigsandfacilities.2FoodAnimalHealthandManagementCenter,CollegeofVeterinaryMedicine,KansasStateUniversity.

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ofweanedpigsduringthistransitionperiodmaybecriticalinimprovingpostweaninggrowth.Creepfeedingstudiesthatevaluatedindividualpigsratherthanwholelittershaveconsistentlydemonstratedthebenefitofcreating“eaters,”whicharepigsthatposi-tivelyconsumedcreepfeed,onpostweaningfeedintakeandgrowth.Identifyingfactorsthatcanincreasecreepfeedconsumptionandtheproportionofpigsconsumingcreepfeedmaybeimportantinimprovingthesuccessofthispractice.

Itishypothesizedthatcreepdietcomplexitymaybeanimportantfactorinstimulat-ingfeedintake.Inpreviousstudies,significantimprovementswereobservedinbothpreweaningandpostweaningfeedintakewhenlitterswerefedacreepdietwithgreatercomplexity.However,noresearchhasbeenconductedtoevaluatetheeffectsofcreepdietcomplexityonindividualconsumptioncharacteristics.Itisalsocommonlyspecu-latedthatweanedpigsthathavepreweaningexperiencetosolidfoodmayfacilitatenon-experiencedpigstodiscoverfoodsourcesandinitiatefeedingwhenthesepigsarehousedtogetherinlargenurserygroups.Thatis,pigsthathavenotconsumeddryfeedmay“learn”fromthosethatareeating.However,evidenceofthissociallearningbehaviorislimited.Therefore,theobjectivesofthisstudyweretodetermine(1)theeffectsofcreepdietcomplexityonpreweaningperformanceandtheproportionofpigletsconsumingcreepfeed(Exp.1)and(2)whethersocialfacilitationoccursbetweeneatersofcreepfeedandpigsthatdidnotconsumeorhadnotbeenofferedcreepfeedinacommercialnursery(Exp.2).

ProceduresTheexperimentalprotocolsusedinthisstudywerereviewedandapprovedbytheKansasStateUniversityInstitutionalAnimalCareandUseCommittee.

Experiment1Atotalof96sows(PICC29)andtheirlitterswereusedinthisstudyconductedatacommercialsowfacilityinnortheasternKansas.Sowsusedinthisexperimentwerefrom3batchesofsowsfarrowedinFebruary2009.Cross-fosteringwasperformedwithin24hafterfarrowing.Atthestartofthecreepfeedingexperiment(d18),sowswereblockedaccordingtodateoffarrowingandlittersizeandallottedto3experimen-taltreatmentsinarandomizedcompleteblockdesign.InTreatment1,litterswerenotprovidedanycreepfeed(nocreep).InTreatments2and3,litterswereprovidedeitherasimpleorcomplexcreepdiet,respectively(Table1).Therewere26replicatesforTreatments1and2and44replicatesforTreatment3.ThehighernumberofreplicatesforTreatment3wasintendedtoincreasethenumberofeatersthatwereusedforExp.2.

Thesimplecreepdietcontained60%milo,32%soybeanmeal,and3%choicewhitegrease,whichwasidenticaltothelactationdietofferedtothesows.Itwasformulatedtocontain1,589kcalME/lband0.97%standardizedilealdigestible(SID)lysine.Thecomplexcreepdietwascomposedof30%pulverizedoatgroatsand25%spray-driedwheywithspecialtyproteinsourcessuchas10%extrudedsoyproteinconcentrate,6%spray-driedporcineplasma,and6%selectmenhadenfishmeal.Italsocontained5%lactoseand5%choicewhitegrease.Thedietincludedverylowlevelsofsoybeanmeal(2.3%)andcorn(6.15%).Thedietwasformulatedtocontain1,585kcalME/lb,1.56%SIDlysine,and23%lactose.Chromicoxidewasaddedtobothdietsat1.0%toserve

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asafecalmarker.Thesimplecreepdietwasinmealform,andthecomplexcreepdietwasinpelletform(2-mmpellets).Bothcreepdietswereofferedadlibitumfromd18untilweaningond21inarotarycreepfeederwithhopper(RotecnaMiniHopperPan,RotecnaSA,Spain).Asinglelactationdiet(1,589kcalME/lb,0.97%SIDlysine)wasusedintheexperiment.Sowshadfreeaccesstofeedthroughoutlactation.Waterwasavailableatalltimesforsowsandtheirlittersthroughnippleandbowldrinkers,respec-tively.

Pigletswereweighedindividuallyatd0(birth),18(startofcreepfeeding),and21(weaning).Asufficientamountofcreepfeedwasplacedinthehopperofthecreepfeederatthestartofthestudy(d18),andtheinitialweightofthecreepfeederwasweighedandrecorded.Feederswereweigheddailytocalculatedailyandtotalcreepfeedintakeforeachlitter.Allcreep-fedpigswereevaluatedforconsumptioncategoryatd20(48haftercreepfeedwasprovided)byevaluatingfecalmaterialforthepres-enceofgreencolorprovidedbythechromicoxidemarkerinthecreepdiet.Onthemorningoftheevaluationday,afecalswabwasobtainedfromeachpiglet.Thepigwascategorizedasaneaterifagreencolorwasvisibleinthefecalsample.Pigletsthattestednegativeonthefirstfecalsamplingweresampledagain3to12hbeforeweaning(d21).Pigletswerecategorizedasnon-eaterswhennogreencolorwasdetectedinanyofthecollectedsamples.Generalhealthofthesowsandpigletswascheckeddaily,anduseofmedicationwasmonitored.Temperatureinthefarrowingfacilitywasmaintainedataminimumof20°C,andsupplementaryheatwasprovidedtothepigletswithheatlampswhenneeded.

Therelationshipbetweencreepconsumptioncategoryandteatorderwasalsodeter-mined.Teatorderwasdefinedasthespecificteat(pair)nursedbyeachpigletwithrespecttotheanatomicallocationofthenursedmammarygland.Inthisstudy,indi-vidualpigscategorizedaseatersweremarkedontheirback,andnon-eaterswereunmarked.Atd20(within24hbeforeweaning),sucklingboutsfrom20litterswerephotographedwithadigitalstillcamera.Litterswithlessthan50%eaterswerechosentoobtainagooddistributionofeatersandnon-eaters.Thephotographofeachsucklingboutwasthenusedtodetermineteatlocationandrankofeachindividualpigletinthelitter.Adistributionofteatorderinthreeclasseswasalsomadeonthebasisofthepreferredteatpairsuckledbythepiglets:anterior(teatpairs1and2),middle(teatpairs3,4,and5),andposterior(teatpairs6and7).

Experiment2Fromatotalof1,024pigsweanedinExp.1,675pigs(PICC29×327,initialBW14.1lband21.2±0.2d)wereallottedto3treatmentsinacompletelyrandomizeddesign.Thetreatmentsforthisstudywere:Treatment1-pigsthatwerenotprovidedanycreepfeedorpigsthatdidnotconsumecreepfeedevenwhenoffered(non-eater),Treatment2-pigsthatpositivelyconsumedcreepfeed(eater),andTreatment3-pigsthatwere52%non-eatersand48%eaters(mix).Eaterswereusedregardlessofthecomplexityofthecreepdiettheyconsumed.Eachtreatmenthad25pigsperpenand9replications(pens).Eachpenwasequippedwithone10-holeself-feeder(Farmweld,Inc.,Teutopo-lis,IL)andacupdrinkertoprovideadlibitumaccesstofeedandwater.TheexperimentwasconductedatacommercialnurseryfacilityinnortheasternKansas.

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Allpigswerefedabudgetof1and2lb/pigofcommercialSEWandtransitiondiet,respectively.PigswerefedastandardPhase2dietuntiltheendofthestudy(d28post-weaning).Thetotalamountoffeedofferedinthefirst3dpostweaningwasrecorded.Todeterminetotalanddailyfeedintakeintheinitial3d,feedwasvacuumedoutofthefeedersandweighed.Pigswereweighedatd0(weaning),3,7,and28postweaningtocalculateforperiodicandcumulativeADG.

DataAnalysisInExp.1,datawereanalyzedasarandomizedblockdesignusingthePROCMIXEDprocedureofSAS(SASInstituteInc.,Cary,NC)withlitterastheexperimentalunit.Themodelincludedcreepdietcomplexityandblockasthefixedandrandomeffect,respectively.Exceptforfarrowinggroup1,eachblockincluded1littereachofthenocreepandsimplecreeptreatmentand2littersofthecomplexcreeptreatment.TheextralittersfedcomplexdietwereintendedtoprovideanincreasednumberofeatersforExp.2.Theeffectsofcreepdietcomplexity,weightcategory,andteatlocationontheproportionofeaterswereanalyzedusingtheChi-squaretestinSAS.Whentreat-menteffectwasasignificantsourceofvariation,differencesweredeterminedusingthePDIFFoptionofSAS.InExp.2,datawereanalyzedasacompletelyrandomizeddesignusingthePROCMIXEDprocedureofSASwithpenastheexperimentalunit.Themodelincludedconsumptioncategoryandblockasthefixedandrandomeffects,respectively.Whentreatmenteffectwasasignificantsourceofvariation,differencesweredeterminedusingthePDIFFoptionofSAS.Totestforevidenceofsocialfacili-tation,theeffectofconsumptioncategorywascomparedwithinthemixpensusingPROCMIXEDofSAS.StatisticalsignificanceandtendenciesweresetatP <0.05andP <0.10forallstatisticaltests.

Results and DiscussionExperiment1Sowshadanaverageparityof4.3±0.4andlactationlengthof21.2±0.2d(Table2).Theaveragelittersizeatd18and21(weaning)was10.7±0.3and10.5±0.3piglets,respectively.Mortalityrateduringthecreepfeedingperiod(d18to21)was1.9%forallthreetreatments.Resultsindicatednodifferences(P <0.74)inpigweaningweights;however,pigsfedthecomplexcreepdiethadgreater(12.9%;P <0.03)preweaningdailygainsandtendedtohavehigher(11.1%;P <0.06)totalgainthanpigsfedthesimplecreepdiet,withnocreeppigsbeingintermediate.Totalanddailygainsoflittersfedthecomplexcreepdietwere4.1%and5.0%higherthanlittersfedthesimplecreepdiet,respectively;however,differenceswerenotsignificant(P >0.58).Likewise,therewerenodifferences(P <0.70)inlitterweaningweights.Thispositiveeffectofincreaseddietcomplexityonpreweaningweightgainsmayberelatedtothequalityofthetwocreepdietsused.Thecomplexcreepdietwasformulatedtomatchthedigestivecapacityofyoungpigs,sofeeddigestibility,palatability,andantigenicpropertiesofthefeedwereconsidered.Thesesamerequirementsweredisregardedinthedesignofthesimplecreepdiet.However,thelackofdifferencesinpigandlitterpreweaninggainsbetweenthecreep-fedandnocreeppigssuggeststhatanybenefitofincreasingcreepdietcomplexitywasinsufficienttoseeappreciableeffects,especiallywhenthedurationoffeedingandtheamountconsumedisconsidered.

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Littersfedthecomplexcreepdietconsumedtwicethetotal(2.73vs.1.37lb;P <0.0006)anddaily(0.91vs.0.45lb;P <0.0006)creepfeedintakeoflittersfedthesimplecreepdiet(Figure1).Creepdietcomplexityalsoinfluencedtheproportionofpigsconsumingcreepfeedinwholelitters(Figure2).Increasingthecomplexityofthecreepdietimproved(P <0.0001)theproportionofeatersfrom28%to68%.Thissuggeststhatthehighercreepfeedintakeobservedinlittersfedthecomplexcreepdietwasduetoagreaternumberofpigspositivelyconsumingcreepfeed.Theproportionofeatersachievedinthisstudyforthecomplexcreepdietwasconsistentwithourpreviousstudies,inwhichthesamecreepdiet,feederdesign,andcreepfeedingdurationwereused.Relativetoallthenon-dietaryanddietaryfactorspreviouslyinvestigated,dietcomplexityhadthegreatestinfluenceincreatingeaters.Thisindicatesthatthecomplex-ityofthecreepdietmaybeoneofthemostimportantfactorsinstimulatingindividualpigsinthelittertoconsumecreepfeed.

Withinthelittersprovidedcreepfeed,therewasnosignificantinteractionbetweencreepdietcomplexityandconsumptioncategoryonindividualpigperformancepriortoweaning(Table3).Pigsthatbecameeatersincreep-fedlitterswerelighter(P <.0001)atd18andatweaningregardlessofthecomplexityofthecreepdiet.Eatersalsotendedtohavelower(P <0.08)preweaningtotalgainsthannon-eaters.Dailygainsofeaterswere7.2%and5.6%lowerthanthoseofnon-eaters,butdifferenceswerenotsignificant(P >0.12).Thedistributionandperformanceofeatersandnon-eatersaccordingtoweightcategorywerealsocompared(Table4).Thereweresignificantdifferences(P <0.0002)inpigweightsatd18andweaning,totalgain,anddailygainsbetweenthebottom,middle,andtopweightcategoryforpigsfedeitherthesimpleorcomplexcreepdiet.Agreater(P <0.0001)percentageofeaterswasobservedamongpigsinthebottomweightcategoryforbothcreep-fedtreatments;47%inthesimplecreepdietand83%inthecomplexcreepdiet.Therewasnointeraction(P >0.50;datanotshown)betweencreepconsumptioncategoryandweightclassonanygrowthparametersineitherthesimpleorcomplexcreeptreatments.Inthecurrentstudy,pigsidentifiedaseaterswere7%to8%smallerinbodyweightandweregaining5%to6%lessthannon-eaterspriortoweaningregardlessofthecomplexityofthecreepdiet.Thehigherproportionofeatersonthebottomweightcategorysuggeststhatcreepfeedingisbeneficialtosmallerpigletswithinlittersasanalternativesourceofnutrientsduringlactation.

Ithasbeensuggestedthatteatordermayberelatedtocreepfeedconsumption,inthatpigsnursingintheposterior(lessproductive)teatsmayconsumecreepfeedmoreread-ilythantheircounterpartsnursinginanterior(moreproductive)teats.Therelation-shipbetweenteatorderandcreepconsumptioncategoryisshowninTable5.Overall,37%,45%,and17%ofthepigswerefoundnursingintheanterior(teatpairs1and2),middle(teatpairs3,4,and5),andposterior(teatpairs6and7)teats.Therewere49%eatersand51%non-eatersinthelittersevaluated.Resultsshowedatendency(P <0.10)fordifferencesintheproportionofeatersaccordingtoteatlocation.Agreaterpropor-tionofeaterswerefoundnursinginthemiddleandrearteats(57%and52%,respec-tively)thaninthefrontteats(38%).Typically,pigletsthatnursefromtherearteatsaresmallerandlesscompetitivethanthosethatnursefromfrontteats.Thelowerabilityofsmallerpigstocompeteattheudderandextractmilkmaypredisposethesepigstoconsumemorecreepfeedwhenitisoffered.Thehigherrateofeatersinthemiddleandrearteatsinthecurrentstudymaysupportthisassumption.

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Experiment2Theeffectofcreepconsumptioncategoryonnurserypigperformanceandweightvaria-tionwithinpensisshowninTable6.Theinitialweightoftheeatergroup(atd21)wasnumericallylowerthanthatofthenon-eatergroupandtended(P <0.08)tobelowerthanthatofthemixgroup.ThelowerinitialweightoftheeatergroupwasexpectedbecauseitwasacharacteristicofthepopulationofeatersweanedfromExp.1.Intheinitial3dpostweaning(d21to24ofage),eatershad43%greater(0.31vs.0.21lb;P <0.01)dailygainsthannon-eaters,withthemixgroupbeingintermediate.Themixgrouptendedtohavehigher(P <0.08)dailygainsthanthenon-eatergroup.Thiswasmainlyduetodifferencesininitialfeedintake(first3dpostweaning)betweenthegroups.Theeatergrouphadhigher(P <0.002)ADFIthanthenon-eaterandmixgroups.Themixgroupalsohadhigher(P <0.02)ADFIthanthenon-eatergroup.Therewereno(P >0.23)differencesinF/Gbetweentheeater,non-eater,andmixgroupsduringtheinitial3-dperiod.

Fromd3to7postweaning(d25to28ofage),therewereno(P >0.66)differencesindailygainsbetweenthethreegroups.Inthefirst7dpostweaning(d21to28),theeaterandmixgroupshad12%to10%higheroveralldailygains,butdifferenceswerenotsignificant(P >0.15).Pigweightsweresimilar(P >0.13)betweenthethreegroupsatd24and28.Fromd29to49,theeatergrouptended(P <0.07)tohavehigherdailygainsthanthenon-eatergroup,withthemixgroupbeingintermediate.Overall,dailygainoftheeatergroupwas6.2%higher(P <0.05)thanthatofthenon-eatergroup,withthemixgroupbeingintermediate.Therewerenodifferences(P >0.14)inpigweightsatd49betweenthethreegroups.Thoughweightdifferenceswerenumerical,itisworthytonotethatdespitestartingatalighterweight,eatersweretheheaviestgroupandwere3%heavier(34.1vs.33.1lb)thanthenon-eatergroupatd49.

Thedifferenceinpostweaningfeedintakebetweeneatersandnon-eatershasbeenfairlyconsistent.Interestingly,mostpreviousstudiesprovidedcreepfeedfor14to21dandpigswereweanedatanolderage(rangingfrom24to31d),whereasthecurrentstudyhadashortercreepfeedingduration(3dpriortoweaning)andpigswereweanedatayoungerage(21d).Theseresultssuggestthatindividualpigsthatdoconsumecreepfeedpriortoweaningconsumemorefeedandachievegreaterdailygainspostweaningevenwhenfedcreepforashortdurationandweanedat3wkofage.Itisnotknownifthesameresponsescanbeexpectedinyounger(<3wk)weaningages.

Atd21(weaning),therewerenodifferences(P >0.16)ininitialpenCVbetweenthethreegroups.However,theweightvariationintheeatergroupwas1.3to1.6percent-ageunitshigherthaninthenon-eaterandmixgroups.TherewerenodifferencesinpenCVatd24,28,and49;however,thereductioninpenCVintheeatergrouptendedtobegreater(-3.2%vs.-0.9%;P <0.06)atd28thaninthenon-eatergroup,withthemixgroupbeingintermediate.Overall(d21to49),thechangeinpenCVfortheeatergroupwasgreater(-5.6%;P <0.03)thanforboththenon-eaterandmixgroups.Theseresultssuggestthatindividualconsumptioncharacteristicsofpigspriortoweaningmaybeanimportantfactorinimprovingpigweightuniformityinthenursery.Thegreaterreductioninweightvariationineatergroupsmaypossiblybedrivenbyfastergrowthofsmallerpigs,especiallyduringthefirstweekpostweaning.

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Creepconsumptioncategoryinfluenced(P <0.0001)thepercentageoffallbackpigsduringtheinitial3dpostweaning(Figure3).Fallbackpigswerethosethatdidnotgainweightorlostweightinthefirst3dpostweaning.Overall,25%ofthetotalpopulationofweanedpigsinthestudydidnotgainorlostweightduringtheinitial3dpostwean-ing.However,eatersofcreepfeedrespondedbettertoweaning,withonly17%consid-eredfallbackpigs.Fornocreeppigsandnon-eaters,28%and29%,respectively,ofpigslostweight.Thisindicatesthatpositiveconsumptionofcreepfeedpreweaningcanreducepostweaninglag,despitealargeproportionofeatersbeingsmallerthannon-eatersandnocreeppigs.

Socialfacilitationisarudimentaryformofsociallearninginwhichindividualsdiscoverresourcesbyfollowinggroupmembersthathavealreadylearnedtoexploittheseresources.Ifsocialfacilitationreallyoccurs,transmissionofinformationinlocatingandconsuminganewfoodsourcebetweenexperienced(eaters)andinexperienced(non-eaters)penmatesmaybeimportantinreducingproblemswithlowfeedintakeinnewlyweanedpigsandimprovingweaningtransition.Inthecurrentstudy,themixgrouphadhigher(P <0.02)ADFIandtendedtohavehigher(P <0.08)dailygainsthanthenon-eatergroupduringtheinitial3dpostweaning.Overall,theperformanceofthemixgroupwasmostlyintermediatetothatoftheeaterandthenon-eatergroups.

Themixpenshad49%eatersand51%non-eaters(Table7).Atd21(weaning),eaterswere1lblighter(P <0.02)thannon-eaters.Fromd21to24,eatershadgreater(0.36vs.0.15lb;P <0.0001)dailygainsthannon-eaters.Thisresultedina62%reduction(1to0.37lb)intheweightdifferencesbetweeneatersandnon-eatersafter3dpost-weaning.Fromd25to28,therewereno(P >0.48)differencesindailygainsbetweeneatersandnon-eaters.However,eaterscontinuedtohavegreater(P <0.04)dailygainsthannon-eatersduringd21to28andd29to49andoveralldailygains(d21to49).Forsocialfacilitationtooccur,weightgainsofnon-eatersinthemixpensshouldbeeither(1)closertotheweightgainsofeatersinthemixpenor(2)greaterthantheweightgainsofthenon-eatergroup.Resultsshowedthatnon-eatersinthemixpensfailedbothcriteria.Infact,theperformanceofeatersandnon-eaterswithinthemixpensweresimilartotheperformanceofseparatepensofeatersandnon-eaters.Thissuggeststhatsocialfacilitationdidnotoccurbetweeneatersandnon-eaters.

Inconclusion,increasingthecomplexityofthecreepdietimprovedpreweaninggainswhencreepfeedwasoffered3dpreweaning.Thehigh-complexitydietimprovedlittercreepfeedconsumptionandtheproportionofeatersinwholelitters.Eatershadlowerpreweaninggains,lighterweaningweights,andtendedtonursemoreinthemiddleandposteriorteatscomparedwithnon-eaters.Individualcreepfeedconsumptioncharac-teristicsinfluencedpostweaningfeedintake,dailygains,weightuniformity,andreduc-tionofpostweaninglag.Socialfacilitationdidnotoccurinweanedpigshousedinlargecommercialgroups.

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Table 1. Composition (as-fed basis) of the simple and complex creep diets used in Exp. 1Ingredient,% Simple1 Complex2

Corn --- 6.25Milo 60.40 ---Soybeanmeal,46.5%CP 31.65 2.32Spray-driedwhey --- 25.00Finegroundoatgroats --- 30.00Extrudedsoyproteinconcentrate --- 10.00Spray-driedanimalplasma --- 6.00Selectmenhadenfishmeal --- 6.00Lactose --- 5.00Choicewhitegrease 3.00 5.00MonocalciumP,21%P 1.35 0.35Chromicoxide 1.00 1.00Antibiotic --- 1.00Limestone 1.35 0.40Zincoxide --- 0.38Salt 0.50 0.30L-LysineHCl --- 0.15DL-methionine --- 0.15Tracemineralpremix 0.15 0.15Vitaminpremix 0.25 0.25Sowaddpack 0.25 ---Acidifier --- 0.20Phytase 0.10 ---VitaminE,20,000IU --- 0.05Total 100.00 100.00

CalculatedanalysisCP,% 19.6 23.9SID3lysine,% 0.97 1.56ME,kcal/lb 1,589 1,585SIDlysine:MEratio,g/Mcal 2.77 4.47Ca,% 0.87 0.79AvailableP,% 0.38 0.561Dietfedinpelletform(2-mmpellets).2Dietfedinmealform.3Standardizedilealdigestible.

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Table 2. Effects of creep diet complexity on pig and litter performance1,2

CreepdietcomplexityItem Nocreep Simple Complex SE P-valueno.oflitters 26 26 44 --- ---no.ofpigs/litterd18(startcreep) 10.8 11.0 10.3 0.3 0.30d21(weaning) 10.5 10.8 10.2 0.3 0.38Weaningage,d 21.3 21.2 21.2 0.2 0.86Pigweights,lbd0(post-fostering) 3.44 3.37 3.48 0.13 0.70d18(startcreep) 12.52 12.43 12.46 0.44 0.95d21(weaning) 14.20 14.04 14.22 0.46 0.74Totalgain(d18to21),lb 1.67ab 1.59a 1.76b 0.07 0.06Dailygain(d18to21),lb 0.64ab 0.61a 0.69b 0.03 0.03Litterweights,lbd0(post-fostering) 36.44 37.04 36.05 1.92 0.90d18(startcreep) 131.90 134.00 127.58 6.66 0.60d21(weaning) 149.16 151.04 145.22 7.21 0.70Totalgain(d18to21),lb 17.24 17.02 17.72 0.73 0.72Dailygain(d18to21),lb 6.66 6.57 6.90 0.31 0.581Threegroupsofsows(PIC,total=96,avg.parity=4.3±0.4)wereblockedaccordingtodayoffarrowingandallottedto3treatments:nocreep=litterwasnotprovidedanycreepfeed,simple=litterwasprovidedasimplecreepdiet,andcomplex=litterwasprovidedacomplexcreepdiet.Datawereanalyzedwithlitterastheexperi-mentalunit.2Creepfeedwith1.0%chromicoxidewasofferedadlibitumfromd18toweaning(21d)inarotaryfeederwithhopper.abWithinarow,meanswithoutacommonsuperscriptdiffer(P<0.05).

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Tab

le 3

. Int

erac

tive e

ffect

s of c

reep

die

t com

plex

ity an

d co

nsum

ptio

n ca

tego

ry o

n pr

ewea

ning

per

form

ance

of c

reep

-fed

pig

s1,2

Sim

ple

Com

plex

P-va

lue

Item

Non

-eat

erEa

ter

Non

-eat

erEa

ter

SEC

ompl

exity

Cat

egor

yC

ompl

exity

×

Cat

egor

yno

.20

379

145

304

------

------

Pigw

eigh

t,lb

d

0(p

ost-f

oste

ring)

3.37

3.35

3.46

3.44

0.13

0.62

0.63

0.87

d

18

(sta

rtcr

eep)

12.6

511

.62

13.0

712

.17

0.44

0.40

<.00

010.

78

d2

1(w

eani

ng)

14.2

613

.14

14.8

813

.84

0.46

0.29

<.00

010.

82T

otal

gain

,lb

1.62

1.51

1.79

1.71

0.01

0.02

0.08

0.84

Dai

lyga

in,l

b0.

630.

580.

710.

670.

030.

020.

120.

931 Th

reeg

roup

sofs

ows(

PIC

C29

,tot

al=

96,

avg.

parit

y=4

.3±

0.4

)wer

eblo

cked

acco

rdin

gto

dayo

ffar

row

inga

ndal

lott

edto

3tr

eatm

ents

:no

cree

p=

litte

rwas

not

pro

vide

dan

ycre

epfe

ed,

simpl

e=li

tter

was

pro

vide

das

impl

ecre

epd

iet,

and

com

plex

=li

tter

was

pro

vide

dac

ompl

excr

eep

diet

.In

thes

impl

eand

com

plex

trea

tmen

ts,i

ndiv

idua

lpig

swer

esam

pled

atd

19

and

20w

ithfe

cal

swab

sto

dete

rmin

econ

sum

ptio

nca

tego

ry.P

igsw

erec

ateg

oriz

edas

anea

teri

fthe

ysho

wed

gree

n-co

lore

dfe

cesi

nat

leas

t1o

fthe

2sa

mpl

ings

;pig

swer

ecat

egor

ized

asn

on-e

ater

swhe

nth

esam

ples

wer

ene

gativ

efor

gree

n-co

lore

dfe

ces.

Dat

awer

eana

lyze

dw

ithp

igas

thee

xper

imen

talu

nit.

2 Cre

epfe

edw

ith1

.0%

chro

mic

oxi

dew

aso

ffere

dad

libi

tum

from

d1

8to

wea

ning

(21

d)in

aro

tary

feed

erw

ithh

oppe

r.

Tab

le 4

. Effe

cts o

f cre

ep d

iet c

ompl

exity

on

suck

ling

pig

perf

orm

ance

acco

rdin

g to

wei

ght c

ateg

ory1,

2,3

Sim

ple

Com

plex

Item

Bott

omM

iddl

eT

opSE

Bott

omM

iddl

eT

opSE

P-va

lue

no.

4519

839

---81

301

67---

---%

oft

otal

1670

14---

1867

15---

---%

eate

rs47

2523

---83

6562

------

Pigw

eigh

t,lb

d

18

(sta

rtcr

eep)

9.04

12.4

315

.83

0.22

8.09

12.9

417

.44

0.20

<.00

01

d2

1(w

eani

ng)

10.1

914

.04

17.7

70.

269.

5214

.73

19.4

00.

20<.

0001

Tot

alga

in,l

b1.

141.

611.

950.

081.

431.

791.

970.

07<.

0001

Dai

lyga

in,l

b0.

430.

630.

720.

040.

570.

710.

770.

030.

0002

1 Thre

egro

upso

fsow

s(PI

CC

29,t

otal

=9

6,av

g.pa

rity=

4.3

±0

.4)w

ereb

lock

edac

cord

ingt

oda

yoff

arro

win

gand

allo

tted

to3

trea

tmen

ts:n

ocr

eep

=lit

terw

asn

otp

rovi

ded

anyc

reep

feed

,sim

ple=

litt

erw

asp

rovi

ded

asim

plec

reep

die

t,an

dco

mpl

ex=

litt

erw

asp

rovi

ded

acom

plex

cree

pdi

et.D

ataw

erea

naly

zed

with

pig

asth

eexp

erim

enta

luni

t.2 C

reep

feed

with

1.0

%ch

rom

ico

xide

was

offe

red

adli

bitu

mfr

omd

18

tow

eani

ng(2

1d)

ina

rota

ryfe

eder

with

hop

per.

3 Wei

ghtc

ateg

orie

sfor

each

pop

ulat

ion:

Top

≥L

east

squa

resm

ean

+1

SD,M

iddl

e=L

east

squa

resm

ean

±1

SD,B

otto

m≤

Lea

stsq

uare

smea

n-1

SD

.

61


Table 5. Proportion of eaters and non-eaters of creep feed according to teat location1

TeatlocationConsumptioncategory

Non-eater Eaterno.ofpigsFront 35 21Middle 30 39Rear 13 14PercentageofpigsFront 62 38a

Middle 43 57b

Rear 48 52b

1Eatersofcreepfeedinalitterweremarked;non-eaterswereunmarked.Sucklingbouts(n=20litters)werephotographedwithin24hbeforeweaningwithadigitalstillcameratodetermineeachindividualpig’spreferredteat(orpair)atd21oflactation.Front=teatpairs1and2;middle=teatpairs3,4,and5;rear=teatpairs6and7.abChi-squaretest:P<0.10.

62


Table 6. Effects of creep consumption category on nursery pig performance and weight variation within pens1,2

Consumptioncategory P-value

ItemNon-eater

(N)Eater(E)

Mix(M) SE Nvs.E Nvs.M Evs.M

no.ofpens 9 9 9 --- --- --- ---Pigweight,lbd21(weaning) 14.11 13.96 14.20 0.29 0.41 0.97 0.42d24 14.77 14.88 15.04 0.26 0.52 0.13 0.34d28 16.38 16.69 16.47 0.40 0.72 0.24 0.39d49 33.11 34.08 33.93 0.93 0.14 0.21 0.80Dailygains,lbd21to24 0.21 0.31 0.28 0.05 0.01 0.08 0.35d25to28 0.40 0.40 0.41 0.45 0.97 0.69 0.66d21to28 0.32 0.35 0.35 0.02 0.15 0.22 0.82d29to49 0.80 0.84 0.82 0.04 0.07 0.29 0.40d21to49 0.68 0.72 0.70 0.03 0.05 0.19 0.46ADFI(d21to24),lb 0.23 0.29 0.26 0.04 <.0001 0.02 0.002F/G(d21to24) 1.06 0.96 0.93 0.09 0.38 0.23 0.75PenCV3,%d21(weaning) 23.8 25.1 23.5 0.8 0.26 0.78 0.16d24 22.3 22.5 21.3 0.9 0.83 0.42 0.29d28 22.9 21.8 21.2 0.9 0.40 0.19 0.63d49 20.7 19.5 19.6 1.0 0.40 0.43 0.96CV4change,%d21to24 -1.6 -2.5 -2.3 0.8 0.39 0.52 0.82d21to28 -0.9 -3.2 -2.3 0.8 0.06 0.26 0.43d21to49 -3.0 -5.6 -3.1 0.8 0.03 0.96 0.021Atotalof675pigs(PICC29×327,initialBW14.2lband21.2±0.2dofage)wereusedwith25pigsperpenand9replicationspertreatment.Groupcomposition:non-eater=non-creepfedpigsandnon-eatersofcreepfeed,creep=eatersofcreepfeed,andmix=51%non-eatersand49%eaters.Datawereanalyzedwithpenastheexperimentalunit.2Alltreatmentswerefedabudgetof1and2lb/pigofacommercialSEWandtransitiondiet,respectively.3Coefficientofvariationwithinpen.4DifferenceinpenCVbetweentwotimepoints:final%CV-initial%CV.

63


Table 7. Postweaning growth performance of non-eater and eater pigs within mix pens (50% non-eaters:50% eaters)1,2

ConsumptioncategoryItem Non-eater Eater SE P-valueno. 113 108 --- ---%oftotal 51 49 --- ---Pigweights,lb d21 14.81 13.82 0.31 0.02d24 15.26 14.88 0.31 0.38d28 17.04 16.58 0.33 0.35d49 33.42 34.02 0.82 0.54Dailygains,lb d21to24 0.15 0.36 0.04 <.0001d25to28 0.45 0.42 0.03 0.48d21to28 0.32 0.39 0.02 0.002d29to49 0.78 0.83 0.03 0.04d21to49 0.67 0.72 0.03 0.0071Atotalof675pigs(PICC29×327,initialBW14.2lband21.2±0.2dofage)wereusedwith25pigsperpenand9replicationspertreatment.Groupcomposition:non-eater=non-creepfedpigsandnon-eatersofcreepfeed,creep=eatersofcreepfeed,andmix=51%non-eatersand49%eaters.Inthemixtreatment,differencesbetweennon-eaterandeaterpigswereanalyzedwithpenastheblockandpigastheexperimentalunit.2Pigswerefedabudgetof1and2lb/pigofacommercialSEWandtransitiondiet,respectively.

1.37a

Litt

er c

reep

fee

d in

take

, lb

4

3

2

1

0

Simple Complex

Creep diet complexity

0.45y

0.91z

2.73b

Total

ADFI

Figure 1. Total and daily creep feed intake of litters (mean ± SE) fed either simple or complex creep diets.abP <.0006;yzP <.0006.

64


28a

80%

60%

40%

20%

0%

Simple Complex

Creep diet complexity

68b

Figure 2. Effect of creep diet complexity on the proportion (mean percent ± SE) of eaters in whole litters.abP <.0001.

Per

cent

age

of

po

pul

atio

n

40%

30%

20%

10%

0%

Creep consumption category

No creep

28a

Eater

17b

29a

Non-eater

Figure 3. Percentage of fall back pigs during the initial 3 d postweaning within each creep consumption category.Fallbackpigswerethosethatdidnotgainweightorlostweightinthefirst3dpostweaning.Nocreep=pigsthatwerenotprovidedcreepfeedpreweaning,non-eater=pigsthatwerenegativeforcreepfeedconsumption,andeater=pigsthatpositivelyconsumedcreepfeed.χ2=18.0;Categoryeffect,abP <.0001.

Effects of Creep Diet Complexity on Individual Consumption ... · Mixing eaters with non-eaters...

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