Nulliparous Anglo-Nubian goats submitted to male effect under contrasting climatic conditions

摘要

Maleeffectapproachinducesandsynchronizesestrousinsmallruminants,butseveralfactorsmayaffectitspotentialusage.TheobjectivewastotesttheeffectofcontrastingclimaticconditionsuponthereproductivebehaviorofnulliparousAnglo-Nubiangoatssubjectedtomaleeffectapproach.Females(n=80)werepre-selectedontheirbodyscoreconditionandevaluatedfortheirreproductivestatus(progesteronelevel).Femaleswerefurtherisolatedfrombucksofprovenfertilityduring60daysandsubmittedtobreedingseasons(BS)of45daysduringthedryperiod(DP)andrainyperiod(RP).ProgesteroneconcentrationduringtheDPwaslower0.54±0.53#951;g/mLthantheRP1.12±1.00#951;g/mL.DuringtheDP,85.0%femalesexhibitedestrusbehaviorwhile95.0%duringtheRP.Mostestrusweredetectedbetweendays11and15onbothperiods.DuringtheDP,meanvaluesforthefirstestrusvariedbetweencyclingandanestrusfemales(15.0±0.00and12.6±2.31days),respectively.DuringtheRP,themeanvaluesforthefirstestrusofcyclingandanestrusfemaleswere11.9±2.57daysand11.2±2.39days,respectively.Samecomparisonforcyclingfemalesduringbothperiodsdiffered(15.0±0.00vs11.9±2.57days),butnotanestrusfemales(12.6±2.31vs11.2±2.39days).TheintervalbetweenestrusduringtheDPwas10.7±6.35daysandduringtheRPwas21.0±1.40days.OverallpregnancyratewashigherforRP(85.0%)thanDP(65.0%),butpregnancyrateinanestrusfemaleswassimilarbetweengroups.Nulliparousdoesareefficientlypronetoestrussynchronizationbymaleeffectusageanddisplayefficientreproductiveperformance,irrespectivelyoflutealstateandclimaticconditions.