Effects of subcutaneous progesterone injection as a short-time estrus synchronization protocol in ewes: a preliminary study

The present study aimed to evaluate the effect of short-time progesterone injection subcutaneously (SC) on estrus synchronization of Baluchi ewes. All ewes received one dose of PGF۲α (۱۵ mg) and then were divided into two groups. In the P۴ group, a combination of progesterone and propylene glycol was subcutaneously injected twice at the three-day interval, and a vaginal sponge was used in the control group for ۶ days.  On day ۶, all ewes received ۴۰۰ IU of eCG. ۴۸h after eCG injection, two rams were introduced into the flock. Blood samples were taken daily from Day ۰ to Day ۱۳ to measure serum progesterone concentration. Ultrasonography was used to observe ovaries and monitor their changes at three-day intervals. In P۴ and control groups, the estrus rate was ۸۸.۹% and ۱۰۰% for P۴ and control groups, respectively; the duration of estrus for the P۴ and control groups was ۸ and ۸.۵ days, respectively (p >۰.۰۵). No significant difference was observed in the size of the largest follicle and the number of follicles more than ۲ mm in diameter between the treatment and control groups. Further studies with some changes and modifications are required for gaining acceptable fertility and prolificacy rates.

Keywords:

Estrus , Synchronization , ewe , progesterone , short-time protocol