Effects of restricted suckling versus artificial rearing on milk production, calf performance and reproductive efficiency of dual purpose Mpwapwa cattle in a semi-arid climate

摘要

TwentypurebredMpwapwaand16crossbredMpwapwacowswithcalveswereusedinanexperimenttocomparerestrictedsuckling(RS)versusartificialrearing(AR)ofcalvesinTanzania.Arandomizeddesignwasused.CalvesremainedwiththeirdamsduringthefirstfivedaysandwerethenallocatedtotheRSorARtreatments;ARcalveswereweanedat75daysofageandwereprovidedwith41itresofmilkdailyfor70days,whileRScalvesstimulatedmilkletdownofthecowandaftermilkingweresuckledbytheirdamsfor30minutes.Allcalvesweregrazedandwereprovidedwithconcentrate,mineralsandwateradlibitum.Milkyieldfromcowsandmilkconsumedbycalveswererecordedfor175daysaftercalving.ReproductivebehaviorofthecowswasdeterminedbyRadio-immuno-assay(RIA)ofmilkprogesterone.Sixofthe18ARcowswereaffectedbymastitiscomparedtoonlyoneoftheRSgroup.Mean(±SE)dailyyieldsofmilkforMpwapwacowsinRSandARwere6.9±0.45litresand7.6±0.41itres(P0.05),respectively.Correspondingvaluesforcrossbreedswere8.6±0.54and8.0±0.591itres(P0.05),respectively.ThedailysaleablemilkforMpwapwacowsinRSandARwas6.9±0.451itresand6.0±0.411(P0.05),respectively;whileforcrossbredcowstheamountswere8.6±0.541itresand6.4±0.591itres(P0.05),respectively.MeandailytotalmilkyieldsforMpwapwaRSandARcowswere8.9±0.441itresand7.6±0.401itres(P0.05)andforcrossbreeds10.6±0.531itresand8.0±0.581itres(P0.05),respectively.Means(±SE)forfatcontentinbucketmilkandresidualmilk,forMpwapwawere3.56±0.25%and4.97±0.25%(P0.05),respectively;andforcrossbreeds3.6±0.31%and6.3±0.31%(P0.05),respectively.MeandailygainsforRSandARcalveswere381±16gand356±16g(P0.05),respectively.SaleablemilkfromRScowswas15.0%higherfortheMpwapwaand34.3%higherforthecrossbredcowscomparedtosaleablemilkfromcowsofeitherbreedwithcalvesunderAR.Bodyweightofcowspostpartumwasnotaffectedbyrestrictedsuckling.MilkprogesteronemeasurementsshowedthattherewasnosignificantbetweentheRSandARtreatmentsfortheintervalfromcalvingtoinitiationofoestrous(progesterone0.5nmol/litre).However,RScowstooksignificantlylongertoshowaregularoestrouscycle(P0.05).