The effect of equine chorionic gonadotrophin (eCG) injection combined with prostaglandin F2α (PGF2α) and gonadotrophin releasing hormone(GnRH) treatment on reproductive performance of Zandi ewes during non-breeding season

In this study,we aimed to investigate reproductive performance in estrus-induced zandi ewes treated with equine chorionic gonadotrophin (ecg) injection in combination with prostaglandin f2α (pgf2α)and gonadotrophin releasing hormone (gnrh) during non-breeding season. the estrous cycle was synchronized using controlled internal drug release (cidr) for 12 days. the ewes were randomly assigned to five groups (n=100 in each group). the first group (control) did not receive hormone injection,the second group (ecg) received 400 iu of ecg at the time of cidr removal,the third group (ecg+pgf2α) received 400 iu of ecg and 1 ml of pgf2α at the time of cidr removal,the fourth group (ecg+gnrh) received 400 iu of ecg at the time of cidr removal and 1 ml of gnrh injection on the day of insemination,and the fifth group (ecg+pgf2α+gnrh) received 400 iu of ecg,1 ml of pgf2α at the time of cidr removal,and 1 ml of gnrh on the day of insemination. the results showed that the heat response rate was higher in all the groups receiving hormonal injections compared with the control group (p < 0.05). in addition,the lambing and parturition rateswere significantly (p < 0.05) higher in the groups receiving gnrh compared with other treatments.in fact,in groups receiving ecg and pgf2α,lambing and parturition rateswere higher than the control group (p > 0.05). in conclusion,use of ecg at the time of cidr removal and gnrh on the day of insemination increased reproductive performance. therefore,it can be applied as a strategy for increasing lambing rate in ewes. © 2016 by razi vaccine and serum research institute.