Bull-specific effect on fertilization rate and viable embryo recovery in the superovulated buffalo (Bubalus bubalis)

This study was conducted to compare fertilization rate and viable embryo recovery rate in superovulated buffalo (n = 64) following insemination with semen from buffalo bulls (n = 5) having different fertility rates as determined by AI. Frozen-thawed semen from fertile bulls with similar post-thaw progressive motility and sperm morphology was used to inseminate buffalo at superovulatory estrus. Fertilization and viable embryo recovery rates differed among bulls, but this bull-specific effect was not related to the overall herd fertility rate as determined by AI in normal cyclic animals. These results indicate that individual bulls differ in their contribution to fertilization of superovulated donors and also to embryonic development, as determined by viable embryo recovery. Moreover, the results also suggest that buffalo bulls can be screened for optimal fertility and embryo recovery rates in superovulated donors. Further studies are warranted to ascertain the factors which contribute to such bull-specific effects.