Comparison of ovsynch and progesterone-based protocol for induction of synchronized ovulation and conception rate in subestrous buffalo during low-breeding season.

The objective of the present study was to compare the impact of ovsynch and progesterone-based ovulation synchronization protocol on ovarian response and conception in buffalo (n=19) exhibiting subestrus during low-breeding season (maximum ambient temperatures and relative humidity ranging from 36-45°C and 30-80%, respectively). Group I buffalo (n=10) were administered ovsynch protocol (d 0 and d 9, 20 µg Buserelin acetate; d 7, 500 µg Cloprostenol sodium; i.m.) followed by AI on days 9 and 10. During the same period, another group of buffalo (n=9) were administered intravaginal progesterone (1.38 g) for 10 days along with the administration (i.m.) of 500 µg Cloprostenol sodium on day 9 and 20 µg Buserelin acetate on day 11, followed by AI on days 12 and 13. With ovsynch, all the buffalo ovulated in response to 1st GnRH and had functional CL (plasma progesterone, 1.61±0.23 ng/ml; corpus luteum, CL, 11.36±0.67 mm) on day 7. Thereafter, subsequent to 2nd GnRH, five buffalo ovulated within 24 h and the remaining five between 24 to 48 h. In comparison, with progesterone-based protocol, a better synchronization of ovulation (P<0.05) was observed as seven buffalo ovulated between 24 and 48 h and the remaining two between 48 and 72 h following GnRH administration. Moreover, in comparison to ovsynch, conception rate was better with progesterone-based protocol (30 vs. 66.7%; P<0.05). In summary, progesterone-based protocol was superior to ovsynch for synchronization of ovulation and subsequent conception rate in buffalo exhibiting subestrus during the low breeding period.