Long versus short term progesterone treatment effects on synchronized estrous characteristics and fertility in sheep and goat in Colombian high altitude tropics

摘要

Theaimofthisstudywastoevaluatetheeffectofshortorlongtermtreatmentswithmedroxyprogesteroneacetate(MAP)spongesonestroussynchronizationandfertilityinewesandgoats.nbsp;Onexperiment1,28ewesofColombianCreolebreedwererandomlydividedin2groups(n=14),group1receivedanintramusculardoseofaluteolyticagent(0.150mgofTiaprost?)and24hourslateraspongewith50mgofMAPwasinsertedduring12days(longtermtreatment);ongroup2thesameprotocolwasused,withthespongeinsertedduring6days(shorttermtreatment).Spongewithdrawalwasdoneatthesametimeinbothgroups.Bloodsamplesweretakenondays0,2,4and6inordertodetermineprogesteroneconcentrations(day0,spongewithdrawal).nbsp;Thenumberofewesinestrouswashigherinthelongtermtreatment(100%)whencomparingwiththeshorttermtreatment(85.7%),however,significantdifferenceswerenotpresentedforintervaltoestrousandestrousduration.nbsp;Ahigheranswerwasobservedonconceptionrateforshorttreatment(75%)thatforlongtreatment(71.42%).Therewerehigherprogesteroneconcentrationsatthetimeofspongewithdrawalinthelongtermtreatment(0.29±0.03ng/ml)whencomparingitwiththeshorttermtreatment(0.11±0.02ng/ml).nbsp;Onexperiment2,48Saanengoats(crossbreed),wererandomlyalocatedinfourgroups(n=12).Forgroups1and2durationofthetreatmentwithMAP(50mg)was16days,whilegroups3and4lastedfor6days.Ongroups2and4,PGF2#945;agonistwasapplied(5mg,Dinaprost)24hoursbeforespongeinsertion.Allgroupsreceivedadoseofhumancorionicgonadotropin(250UIofhCG)atthetimeofspongewithdrawal,andthespongewithdrawalwasdoneatthesametimeforallthegroups.BloodsamplesweretakenforprogesteronedeterminationbyRadioimmunoassayondays-6,-4,-2,0,2,4and6(Day0,spongewithdrawal).nbsp;Significantdifferenceswerepresentedforgoatsinestrous,withgroup4(shorttreatment)showingthelowestvalue(50%).Asonexperiment1,significantdifferencewasnotpresentedamongtreatmentsforintervaltoestrousandestrousduration.Higherpregnancyrateswereevidencedintheshorttermtreatments91.66%(group3)and83.33%(group4)incomparisonwithlongtermtreatments75%(group1)and66.7%(group2),likewise,conceptionrateinlongtermtreatment(group1(81%)andgroup2(72.7%))waslower,comparedwiththeshorttermtreatments(group3(91.6%)andgroup4(100%)).Onexperiment2,fromday-6untilspongewithdrawal,lowerprogesteronelevelswerefoundinlongtermtreatments.nbsp;Itisconcludedthatshorttermtreatmentshaveacomparableeffectivenessforestrousinduction,whencomparedwithlongtermtreatmentsinsheepandgoat,itisalsoobservedthatshorttreatments,althoughachievingalowernumberofestroussigns,seemstobemorefertilethanthosepresentedinfemalesunderlongtermtreatments,itsuggeststhattheobservedphenomenaofsubfertilityinlongtermtreatmentsmaybenbsp;probablyduetosublutealprogesteronelevelsatthemomentofspongewithdrawalinthelastones.