Effects of genotype and FSH dose on estrus and ovarian response of Boran and Boran x Holstein Friesian cows in Ethiopia

摘要

Thisstudyutilized27Boranand20BoranxHolsteinFriesiancows6-8yearsofage.A7-dayCIDRtreatmentwasinitiatedonDay1,andcowsweretreatedonDays4-7with200,250,or300IUPluset?administeredat12-hourintervalsinadecreasingdoseregimen.ProstaglandinF2#945;wasgivenonedaybeforeCIDRwithdrawal,andcowsweremonitoredfor84hourstodeterminetheonsetanddurationofestrus.Ovarianresponsewasassessedbycountingthenumberofcorporalutea(CL)viatransrectalultrasonography.Theproportionofcowsthatexhibitedestrusinresponsetotreatmentwas76.6%andwashigher(P=0.003)forBoranthanforBoranxHolsteinFriesiancrosses.ThemeanintervalfromCIDRremovaltotheonsetofestruswas20.4±1.8hours;thisintervalwasnotaffected(P.10)bygenotypebutwasaffectedbyPluset?dosewithashorter(P0.01)interval(10.8±3.3hr)forcowsreceiving250IU.Durationofestruswasnotaffected(P0.10)bygenotypebutwasinfluencedbydosewithashorter(P0.009)durationofestrus(16.8±2.1hr)incowstreatedwith250IUPluset?.Borancowshadahigher(P0.03)numberofCL(10.1±0.7)thanBoranxHolsteinFriesiancrosses(7.2±0.9).Resultsindicatethat,underconditionsofourstudyinEthiopia,BorancowshavebetterovarianresponsetoexogenousgonadotropinsthanBoranxHolsteinFriesiancrosses.