Effect of Different Doses PMSG on Estrus Synchronization and Fertility in Awassi Ewes Synchronized with Progesterone During the Transition Period

Abstract

Summary The aim of the present study was to evaluate different of doses PMSG on estrus synchronization and fertility in Awassi ewes synchronized with progesterone during The transition period. A total of 92 ewes were used in this experiment. All ewes were treated with a vaginal sponge containing 30 mg fl uorogestone acetate (FGA) inserted into the vagina of the ewes for 12 days. All animals were divided into four groups randomly and a single intramuscular (IM) dose of PMSG (group 1, 300 IU, n=21; group 2, 400 IU, n=27; group 3, 500 IU, n= 25), group 4 (n=19) was injected with 1 ml normal saline solution and as served control group at time of sponge removal. The interval between the withdrawal of the sponges and estrus was observed 40.82±1.21 h, 40.20±1.14 h, 38.7±1.07 h and 41.79±1.72 h in groups 1, 2, 3 and the control group, respectively. Estrus responses were similar in all groups (group 1, 81.0%; group 2, 92.6%; group 3, 92.0%; control group, 73.78%). There were no statistically signifi cant differences (P>0.05) between the treatment groups and the control group for the onset of estrus or estrus response. The duration of estrus was shorter in group 1, compared to the control group (24.9±0.85 hr vs. 29.07±1.31hr), and that this difference was statistically signifi cant (P<0.05). Pregnancy rates were 82.35%, 80.0%, 82.60% and 78.5% in groups 1, 2, 3 and the control group, respectively. Lambing rates were obtained 100.0% among all the groups, or litter size (1.07 to 1.21) did not differ between the treatment groups and the control group. As a result, different doses of PMSG in Awassi ewes synchronized with progesterone during the transition period had similar effect on estrus synchronization and fertility parameters.