Changes in milk protein content as indicator of energy balance and fertility in dairy cows

摘要

Thepurposeofthisstudywastoevaluatethepotentialsofusingchangesinmilkproteincontent(dmPc)asindicatorofenergybalanceandfertilityindairycows.Milksamplesandfertilitytraitsof13primiparousand47multiparous(F1)FriesianxBunajidairycowswereanalyzed.Fournbsp;fertilitytraits:daystofirstinsemination(DFI),daysopen(DO),non-returnrate56daysafterfirstinsemination(NRR56)andnumbersofinseminationperconception(NIC)wereevaluated.Themilksampleswereanalysedweeklyformilkfatcontent(MFC)andmilkproteincontent(MPC).Thesevariableswereusedtocalculatetheothermilkcompositionvariables;milkfatyields(MFY),milkproteinyield(MPY),fat-proteinratio(FPR)andthechangevariables.Thesearethecurrentminusthepreviousvaluesofthemilkmeasuresinquestion.Thatischangeinmilkfat(dmFc),changeinmilkprotein(dmPc),andchangeinfat-proteinratio(dFPR).Yieldvalueswereinkilograms/day(kg/day);contentvalueswereinpercentages(%)andratioswereunitless.Theenergybalance(EB)wascalculatedfrommilkyieldandmilkcompositionmeasures.nbsp;Theresultsshowedthatthesinglemostinformativemilkcompositionvariablethatcouldbeusedassuitableindicatorofenergybalanceandfertilityindairycowsisthechangesinmilkproteincontent(dmPc).IthasstrongrelationshipwithbothEBandfertilityofthecows.Itisthereforeconcludedthatnbsp;thesuitableindicatorforevaluationofEBstatusandfertilityinlow-mediumyielddairycowsischangesinmilkproteincontent(dmPc).nbsp;