comparative study of estrus induction with long-term and short term progesterone in ewes during non-breeding and breeding seasons

ABSTRACT

The objective of this trial was to compare the efficacy of long-term and short-term progesterone treatments on induction of estrus and pregnancy rate in Rahmani ewes during non-breeding and breeding seasons. Twenty-four animals were randomly grouped for two treatments with intravaginal progesterone device Group A] during breeding season and Group B] during non-breeding season. Furthermore, both groups were subdivided into two treatments Al and BI for short-treatment [7 days] and A2 and B2 for long-treatment [12 days]. The progesterone treatment was a vaginal sponge containing 40 mg medroxy progesterone acetate [MAP]. Equine chorionic gonadotrophin [eCG] and cloprostenol [PGF2 alpha] were intramuscularly administered to all ewes at the time of sponge removal. After the detection of estrus, the animals were hand-mated naturally. During the breeding season, mean percentages of estrus and pregnancy were 100% and 83.33%, respectively in both the short-term and long-term treated groups. During the non-breeding season, the average values of estrus were 100% in short-term and 100% for long-term progesterone treatment, but the pregnancy rates were 66.67 and 50.00% in the short- and long-term treated groups, respectively. The treatment with progesterone for short-term [7 days] was effective to induce estrus in sheep during both breeding and non-breeding seasons