The experiment was carried on 40 post partum anoestrus buffaloes during breeding season. The buffaloes were divided in four equal groups, Group I was treated with Ovsynch protocol + PRID which removed on 7th day and administration of GnRH @ 10 mcg i/m on day of AI. Group II treated with Progesterone impregnated intra-vaginal device which was removed on 7th day and GnRH @ 10 mcg i/m was administered on the day of AI. Group III was treated by using Ovsynch protocol alone and Group IV was kept as untreated control. Fixed time Artificial Insemination was performed in responded animals. Ovarian activity measurements studied on 0, 7th and 10th day of experimentation were found to be 3.94 ± 0.13, 9.84 ± 0.64 and 10.546 ± 0.18 mm during breeding season. Follicular developments were found significantly (p<0.01) greater on day 10th than day 0. However, overall follicular growth was observed significantly (p<0.01) greater on day 10th and the size of corpus luteum were recorded significantly greater (p<0.01) on day 7th. Follicular size improved (10.86 ± 0.71 and 8.84 ± 0.67 mm) with treatment of Ovsynch + PRID protocol as compared to PRID + GnRH (10.50 ± 0.59 and 7.13 ± 0.37 mm) and Ovsynch alone (10.25 ± 0.28 and 7.63 ± 0.63 mm) during breeding season in post partum anoestrus buffaloes. All the hormonal protocols have improved follicular size as well as size of corpus luteum in comparison with control group in post partum anoestrus buffaloes.

Highlights

• Ovsynch + PRID protocol can be effectively used for improving follicular size estrus induction in post partum anoestrus buffaloes.
• Recording of follicular size, CL diameters through ultrasonography is useful to interpret expected reproductive response expressed as number and quality of follicle for future fertility of buffaloes.