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Background: Estrus synchronization may be a tool to overcome silent estrus and breeding seasonality, the major factors limit the reproductive efficiency of indigenous buffalo (Bubalus bubalis) in Bangladesh. The present study was carried out to evaluate estrus responses and conception rate in response to the Fixed Time Artificial Insemination (FTAI) of indigenous buffaloes (n=97) with Ovsynch protocol.
Materials and Methods: Buffaloes (morning and evening groups) were synchronized in three different seasons of Bangladesh. Estrus was synchronized according to Ovsynch protocol (a sequence of GnRH - PGF2α - GnRH treatments). Each animal received a single artificial insemination with frozen semen from Mediterranean buffalo bulls at 18 to 20 hours (fixed timed AI) following second GnRH injection. Diagnosis of conception was performed by real-time transrectal ultrasonography using an ultrasound scanner on Day 40 post-AI.
Results: Ovsynch treatment induced the estrus signs in all buffaloes. The conception rate was 56.70% (55/97) and pregnancy rate was 31.96% (31/97) in indigenous river type buffaloes of Bangladesh. Though the difference of conception and pregnancy rate was insignificant (p˃0.05) among seasons, the conception rate was varied from 44% to 64.87% and the pregnancy rate varied from 28% to 35.14% in different seasons of Bangladesh. The conception rate was also varied depending on the time of administration of hormones as well as the time of insemination. The conception rate was the highest (64.87%) in late autumn (Hemonto) season when the temperature was low (17-22°C) and the higher in morning group (61.54%).
Conclusion: The Ovsynch protocol effectively synchronized estrus in indigenous river type buffaloes with a reasonable conception rates after FTAI. Estrus synchronization and FTAI could be applied for effective breeding program of buffalo in Bangladesh, though further studies are needed to increase the conception rate.