Effect of Pregnant Mare Serum Gonadotropine (PMSG) and Gonadotropin-Releasing Hormone (Gnrh) Combination on Estrous Synchronization in Farahani Ewes

Estrus synchronization is an important technique in management of reproductive function in ewes. The objective of this study was to evaluate the effect of using combination of PMSG and GnRH hormones on estrus synchronization during the breeding season in Farahani ewes. Forty mature Farahani ewes, weighting 48.97±0.55 kg, BCS 3.04±0.3, were used in this study. The experimental ewes were synchronized using CIDR for a period of 10 days and injected 2 ml PGF2α at day 0 and these ewes randomly assigned to four groups. The control group (group 1; n=10) did not receive any treatment. Ewes in group 2 were injected with 150 IU PMSG and 1 ml Buserellin acetate after CIDR removal. The group 3 ewes injected with 100 IU PMSG and 2 ml Buserellin acetate after CIDR removal. The group 4 of ewes were injected with 300 IU PMSG and 0.5 ml Buserellin acetate after CIDR removal. Estrus detected after CIDR removal, then, the ewes were mated with Farahani rams. After parturition, the reproductive parameters of ewes were recorded. The estrus rate was constant in all groups. The lamb weight in group 4 was significantly different (P>0.05) compared with other groups. Pregnancy rate was not significantly meaningful among treatments. The lowest glucose and progesteron concentration was achieved in group 4 that was significantly different (P > 0.05) compared to other groups. The data of birth weight also didn’t show significant differences (P>0.05) between the treatment groups. There was no significant difference in abortion and stillbirths between treatments (P˃0.05). The results showed that the combination of two PMSG and GnRH hormones in the estrus synchronization program could increase the lambing rate up to 0.7.