Effect of progesterone and prostaglandin analogue-based synchronization programs on the follicular dynamics and conception rate at two different breeding seasons in subtropical ewes [electronic resource].

Includes references.

The present study aimed to investigate the effect of using progesterone- and prostaglandin analogue-based synchronization programs on follicular dynamics and conception rate in subtropical ewes during winter and spring breeding seasons. A total of 80 ewes were assigned into 4 equal groups; Sponge-Spring (SS), Sponge Winter (SW), PGF₂α-Spring (PS) and PGF₂α-Winter (PW). In PGF₂α--based protocols, 2 injections of natural PGF₂α with 10 days apart were used. In progesterone-based protocol, one intravaginal progestagen impregnated sponge inserted for 14 days. The estrus behavior was detected every 4 hrs after the second injection of PGF₂α or the withdrawal of sponge (Day 0) until the estrus signs were no longer detected using teaser rams. Mating with fertile rams was scheduled every 12 hours during heat. Ultrasonography examinations were started at day 0 and every 12 hrs for 5 days. The results showed that season significantly affected the duration of estrus (P < 0.05) which was longer in winter than spring (SW; 29.6 ± 3.0, PW; 27.1 ± 1.8 Vs. SS; 21.7 ± 2.0 PS; 16.3 ± 3.0 hrs), while the onset of estrus started at the same times in all groups.

Summary in Arabic.