Comparison between short- and long-term of estrus synchronization with different doses of pmsg in noemi ewes

Two experiments were performed on 60 ewes and 7 Noemi rams were used. Two and 4 groups were designed in Experiment I and II respectively. Each group has 10 ewes. In experiment I, intra-vaginal sponges, containing 40 mg of FGA, were left in the vagina of groups control and G1 for 5 d.All ewes received GnRH at time of sponge insertion and time of sponge removal; ewes received prostaglandin F2α and only PMSG hormones at the doses of 500 IU in G 1. Experiment II, the protocol followed the same protocol of Experiment I for control and G1. As for G2 and G3 followed protocol in G1 but the dose of PMSG were 700 in G2 and 1000 IUin G 3. Ewes were naturally matted 36 hours after sponge removal. All ewes in both Exp I and II showing estrus, except one ewe not showing estrus in control group of Exp II.In Exp I the pregnancy rates in control and G1 were 40 % and 70 %, respectively. However, in Exp II the pregnancy rate were 50, 90, 90 and 70% in control, G1, G2 and G3, respectively. The mean time from sponge out to show estrus were longer in control (55.9±1.9 and 58.44±3.5 h. in Exp I and II, respectively) compared to other groups. The difference was statistically significant (P<0.05).The mean litter sizes were higher in G1, G2 and G3 of Exp II which are 1.33, 1.55 and 1.71, respectively. The difference was not significant to Exp I. It was concluded that short term treatment using FGA and PMSG administration in the Noemi ewes may be useful to condense estrus and in order to increase pregnancy rate.