Characterization of the estrous cycle by means of profiles of steroids (progesterone, 17 - B estradiol) in the Coste?o Con Cuernos breed (Bos taurus) in the Colombian tropics

摘要

IntheColombianTropics,valleyofSin#250;River,westudiedestrouscyclesin10Coste#241;oConCuernos(CCC)breedcowsduring120daysstartingfromthecalving.Bloodcollectionhasbeenmadeeachthreedaysfromtherestartofestrousactivitytodeterminethehormonalprofiles(progesterone,17b-estradiol)byradioimmunoassaytechnique(RIA),withthepurposeofnbsp;knowingthecharacteristicsandtoevaluatethephasesoftheestrouscycle.Thepostpartumanestrusperiod,heat-detectionefficiency,estrouscycleduration,andprogesteronelevelsvariationthroughestrouscycleweredetermined.Additionally,thebodyweightatcalvinganditschangesduringlactationwereevaluated,aswellastherateofgrowthoftheoffspringasanindirectindicatorofmaternalability.Weobservedestrouswithovulationstartingfromthe51dayspostpartumandestrousclusterincertaindays.Progesteroneprofilespresentedminimumlevelssustainedduringendoffollicularphaseuntilthethirddayoftheestrouscycle;afterthisaninflectionofthecurvewasapparent,withvariationsintheprogesteronelevelsthroughtheearlylutealandhalflutealphases.Theaverageofmaximumlevelofprogesteronewasof8,64ng/ml,towardtheday15oftheestrouscycle.Thenutritionalstateofthecowsatcalving,thesameasitsvariationthroughthepostpartumperiod,showedrelationshipwiththerestartofreproductiveactivity.Heat-detectionefficiencysupportedbyprogesteronelevelswas74%.17b-estradiolprofilesshowedthepresenceoffollicularwavesandthenumberofwaveswasrelatedwithestrouscycledurationthatwas21.14days(min19,max23).