Strategic supplementation of bypass protein and fat to dual purpose cattle in the colombian tropics during the dry season

[摘要] Theeffectofstrategicsupplementationwithbypassproteinandfattodualpurposecows(1/2European;1/2Zebu)wasstudiedfromcalvingto188daysoflactation,duringthedryandbeginningofthewetseasonintheColombiantropics.FortyF1cowsoffourbreedinggroups:NormandyxZebu(NxZ=14);BrownSwissxZebu(BSxZ=10);GyrxHolstein(GxH=7)andHolsteinxZebu(HxZ=9)grazingBrachiariadecumbensweresupplementedwiththreelevelsofbypassprotein(0,0.5and1kgdrymatterperday)ofCottonSeedMeal(CSM)andamixtureofurea,sulphurandacombinedsourceofprotein,starchandoil(0.5kgdrymatterperdayofricepolishing,RP);thecontrolgroupgrazedBrachiariadecumbenswithoutsupplements.Apositive(Plt;0.05)effectwasobservedintotalanddailymilkproductionduetosupplementation.CowsinalltreatmentslostweightbutthosegivenzeroCSMhadthehighestweightlosses(-299g/day)(Plt;0.05).Calvesoutofsupplementedcowsgainedfaster(Plt;0.05)andhadheavierweaningweights(Plt;0.05)thancalvesinthecontrolgroup.GyrxHolsteinF1cowshadsignificantly(Plt;0.05)greatertotalanddailymilkproduction.Reproductiveperformancewassignificantly(Plt;0.05)betterinallsupplementedgroupscomparedwiththecontrolgroup(66.7vs30%pregnancyrates).NormandyxZebuandHolsteinxZebuaveraged74.6%pregnancyrateagainst34.3%forBrownSwissxZebuandGyrxHolsteincows.Inconclusion,supplementedcowsshowedbettertotalproductiveperformanceduetolowerweightlosses,highermilkproduction,betterpregnancyrateandheaviercalves.

[学科分类] 农业科学（综合）