Abstract
The aim of this study was to monitor and compare the ovarian follicular dynamics and serum progesterone profiles in heifers (HE) and buffalo cows (BC) during the Ovsynch protocol. A total of 17 apparently healthy female buffaloes received treatment regimen (8 HE and 9 BC). Twenty-two buffalo cows were used as reference for conception rate, control heifers and control buffalo-cow (CHE, n=10 and CBC, n=12). The heifers and buffalo-cows were cyclic. All treated animals were injected with GnRH on Day 0, PGF(2 alpha) on day 7, and GnRH on day 9, and AI 16 h later. Ovarian structures were monitored daily by ultrasound and blood samples were collected for progesterone (P-4) analysis. All the heifers (8) and five of the cows had F>8 mm (LF) at the first GNRH injection. The first GnRH injection resulted in ovulation in seven HE (87.5%) and all five BC (100%) which had LF. Following the second GnRH, ovulation occurred in 100% of the HE and 88.8% of the BC. Ovulation began earlier in the BC (10.41 +/- 7.6 h) following the second GnRH and extended for longer (22.6 +/- 5.4 h) in the HE. The average P 4 concentrations of the HE were slightly greater than those of the BC on day 7 (P = 0.04). The conception rate in the HE was 62.5% (5/8) and was 60% (6/10) in the CHE, while only 11.11% (1/9) in the BC and 58.3% (7/12) in the CBC. It is suggested that the unsatisfactorily low conception rate in buffalo-cows-compared to heifers-may be attributable for the early ovulation and sub-functional CL.