Production of F1 Bos taurus x Brahman cows bred to Brahman bulls and Brahman cows bred to F1 Bos taurus x Brahman bulls versus Brahman. 2. Cow production

摘要

ProductionofF1BostaurusxBrahmancowsbredtoBrahmanbullsandBrahmancowsbrednbsp;toF1BostaurusxBrahmanbullsversusBrahman.nbsp;2.Cownbsp;productionnbsp;ThisbreedingprogramwascarriedoutinherdsHIandHIIinseasonallyfloodedsavannainApurestate,Venezuela.InHI,1598cowswerebredbetween1983and1986inmultisireherdsaccordingtobreedofbull.Brahman(B)cowswerebredtoB(control),F1ChianinaxB(Group1)andF1AngusxB(2)bulls,aswellasF1ChianinaxBcowstoBbulls(3).InHII,2036cowswerebredbetween1983and1985:BcowstoB(control),toF1Marchigiana(M)xB(4),toF1Simmental(SI)xB(5)andtoF1Charolais(CH)xB(6)bullsandF1M(7),F1SI(8)andF1CH(9)cowstoBbulls.Leastsquarestechniqueswereusedtoanalyzethefollowingevents(offspringpresent:1,notpresent:0):pregnancy(P),calving(C)weaning(W),18months(18M)andweightproducedpercowintheherdatweaning(WWCH)andat18months(18MWCH)includinginthemodelthefixedeffectsof:breedgroup(G),birthyear(Y)andcowage(D).nbsp;InHI,GwassignificantforP(P0.05)andtheothertraits(P0.01),YforWand18M(P0.05)andtheothertraits(P0.01),andDforallcharacteristics(P0.01).InHII,GwassignificantforPandC(P0.05),andWandWWCH(P0.01),anddidnothaveanyeffecton18Mand18MWCH;Ywasnotsignificantforanytrait,butDwas(P0.01)forallofthem.nbsp;InHI,adjustedmeansforP,C,W,18M,WWCHand18MWCHwere77.4±1.5,72.0±1.7,68.0±1.7,65.6±1.8%;101±2.6and171±4.7kg,theunadjustedmeansbeingslightlyhigher.InHII,adjustedmeansforthesametraitswere:78.6±1.3,71.5±1.4,67.3±1.5,57.3±1.8%;126±2.8and135±4.2kg,theunadjustedmeansbeingslightlylower.InHI,deviationsofcrossbreedsfromBwereforP,C,W,18M,WWCHand18MWCHfor(1)0,3,2,0,4,1%;(2)-8,-3,-5,-4,3,1%;(3)6,14,15,15,28,25%.InHII,thedeviationsfromBwerefor(4)-5,-8,-10,-3,-1,-2%;(5)-1,-6,-7,-4,3,nbsp;nbsp;-5%;(6)-3,-1,0%,nodata,17%,nodata;(7)-13,-16,-20,-12,-6,-3%;(8)-2,-2,0,-4,21,8%;(9)11,10,13%,nodata,25%,nodata.nbsp;Reproductiveefficiencyofnbsp;F1cowswasnegativelyinfluencedbytheirhighmilkproduction(highweaningweightsof3/4Bosindicus1/4Bostaurus)exceptinF1Chianina,andF1Charolais,buttheirWWCHwasbetween21and28%higherthanforB,exceptinF1M,whichwere6%inferior.BcowsbredtoF1nbsp;bullswereinferiorinPcomparedtobeingbredtoBbullsanddeviatedfromthecontrolforWWCHbetween-1and17%.For18MWCHbreedgroups(1),(2),(3)and(8)were1,1,25and8%superiortoB,theotherswereequalorupto5%belowB,however,onlytheadvantageof(3)wassignificant.