Vol. 10, Special Issue 11 (2021)

Author(s):
Hariom, Harpreet Singh, Ravi Dutt, Sonu and LC Ranga

Abstract:
The study was attempted to evaluate the efficacy of the (Ovsynch) modified estrus synchronization protocols in combination with different durations of progesterone (P4) therapy (using P4 impregnated intravaginal sponges) during breeding (November-January; autumn season) and non-breeding (May-July; summer season) seasons in Nali×Rambuillet crossbred ewes. Three GnRH-PGF2α-GnRH protocols were employed with modifications in three groups (during one breeding and one non-breeding season) sequentially on days 0, 5, 7 in protocol-A; on days 0, 8, 9 in protocol-B and on days 0, 12, 13 in protocol-C combined with different durations of P4 therapy (5, 8 and 12 days of sponge insertion in protocol-A, -B and -C, respectively). Each experimental group comprised of randomly selected 50 ewes. A total of 5 proven breeding rams in each group were used for mating with the ewes exhibiting estrus. Serum estradiol-17β concentration on the day of estrus during non-breeding season was significantly (p<0.05) higher in ewes treated with protocol-B compared to those with protocol-A. Similarly, during breeding season also, the estradiol concentration was significantly (p<0.05) higher on the day of estrus in ewes subjected to protocol-B compared to those with protocol-C.