EFFECT OF OPU SESSION AT INDUCED AND RANDOM STAGES OF THE OVARIAN CYCLE ON OOCYTE YIELD AND IN-VITRO EMBRYO PRODUCTION IN ONGOLE AND GIR HEIFERS

The present study was carried out to evaluate the effect of OPU session i.e OPU performed at known stage of cycle (OPU1) vs OPU performed at unknown stage of cycle (OPU2), on oocyte yield and in-vitro embryo production in two different Bos indicus breeds i.e., Ongole (n=6) and Gir (n=6) heifers, aged 2-4 years. OPU 1 was carried out on day 9 (luteal phase) of induced cycle and after a resting period of 3-4 weeks OPU2 was performed at random stage of cycle. A total of 24 OPU sessions were performed in 12 animals. The mean antral follicle count (AFC) (32.58±2.22 and 30.50±2.16), cumulus oocyte complexes (COC) recovery (24.58±2.50and 22±1.95), viable oocyte yield (21.25±2.20and 19.33±1.72) and embryos produced (5.91±0.9and 6.66±1.13) in OPU 1 and OPU 2 respectively,did not show significant variation (P>0.05). Similarly the breed of the oocyte donor had not shown any effect on OPU-IVEP parameters. The results suggest that the stage of estrous cycle did not impact the efficacy of OPU. Ongole and Gir heifers, both being Bos indicus category, performed uniformly in both OPU sessions.