Effects of restricted suckling versus artificial rearing on performance and fertility of Bos taurus and Bos indicus cows and calves in Tanzania

[摘要] TwelveBoranand12exoticcows(FriesianandAyrshire)withtheirnewborncalveswereusedinanexperimenttoevaluatetheeffectsofrestrictedsuckling(RS)ongrowthrateofthecalvesandmilkyieldandreproductiverateofthecowscomparedtoartificialrearing(AR).Ineachbreed,theanimalswererandomlydividedintotwogroups:RSandARaccordingtocalvingdate.Cowsandcalvesinbothgroupswerekeptunderthesameconditions.CalvesunderARtreatmentwereremovedfromtheirdams3daysaftercalvingandfedmilkfrombuckets.CalvesunderRStreatmentwereallowedtosuckletheirdamstwicedailyfor30minutesaftermilking.TheaveragedailyweightgainoftheRScalveswashigher(Plt;0.05)thanthatofARcalves(0.45vs.0.40kg/day).Milkconversionperkilogramweightgainwas3.9kgforRScalvesand4.5kgforARcalves(Plt;0.05).AveragetotalmilkyieldofRScowswas26%higher(Plt;0.05)thanthatofARcows(9.1vs.7.2kg/day).SaleablemilkofRScowswas37%higher(Plt;0.01)thanthatofARcows.Therewasnodifferenceinpostpartumintervaltofirstoestrus(97daysforRScowsand93daysforARcows)ormilkprogesteroneconcentrationsbetweencowsinthetwosystemsofcalfmanagement.TwentyfivepercentofthecowsinARtreatmenthadmastitiswhilenocasewasobservedintheRScows.Thereweredifferencesbetweenbreeds:Borancalveshadhigher(Plt;0.001)dailyweightgain(0.46vs.0.38kg/day)andbettermilkconversionperkgweightgain(3.1vs.5.3kg)thanexoticcalves.Borancowshadlowerdailymilkyieldsthanexoticcows(4.3vs.12.0kg),butgained28kgliveweightin6monthspostpartumwhileexoticcowslost9kg.Restrictedsucklingisconsideredtobeamoreappropriatesystemthancalfremovalandartificialrearingformanagingcowsandcalvesandcanberecommendedespeciallyforsmall-scalefarmers.

[学科分类] 农业科学（综合）