Serum progesterone levels at 0, 5, 10, 15 and 20 days of the estrous cycle in Simmental x Cebu, Holstein x Cebu, Romosinuano x Cebu heifers, maintained under colombian humid and hot tropical conditions

摘要

InthenothwesternpartofColombia,74weanedheifers[28HolsteinxCebu(HC),14SimmentalxCebu(SC),20Romosinuano(R),and12Cebu(C)],underconditionswhichwouldallownormalanimalphysiologicalperformancewereemployedastodetermineserumprogesteronelevelsduringfollicular(FF),earlyluteal(EL),midluteal(ML)andlateluteal(LL)phasesoftheestrouscycle.nbsp;Therewerenotstatisticaldifferencesamongvaluesobtainedat0,5,10,15and20daysoftheestrouscyclewhencomparingSCandHCgroups.HighervalueswerefoundingroupsSCandHCinthefollicularphase.nbsp;SignificantdifferenceswereencounteredbetweengroupsSCandRatELandMLphasesandbetweengroupsSCandCattheLLphase.HCgroupwasdifferentfromgroupRatLFandLLphases.TheHCgroupshoweddifferenceswithgroupRatLLphaseandwithgroupCattheMLandLL.GroupRdifferedfromgroupCatEL,MLandLLphases.TheprogesteronelevelscurveintheRgrouphadadifferenttendencyascomparedtothecorrespondentonesofanothergroups.ItshowedlowervaluesduringFphaseandgreatervariationinlutealactivitybeforeMLandLLperiods.ThesechangescouldmodulatefolliculardevelopmentanddeterminetheendocrinemodelwhichcontributetoagreaterreproductiveefficiencyintheRgenotype.