Effects of different lots of semen from the same bull on in vitro development of bovine oocytes fertilized in vitro.

The effectiveness of 8 different lots of semen from the same bull on the in vitro development of bovine oocytes fertilized in vitro was evaluated. Cleavage and development rates to the blastocyst stage were not significantly different among the 8 lots of semen. However, the cleavage and development rates varied no more than +/-11 and +/-6%, respectively, in overall rates. A maximum of 35.2 and 27.9% difference in cleavage and development rates to the blastocyst stage, respectively, was observed using a single straw from the same semen lot for insemination in 4 trials. This variation tended to be higher than that observed for the cleavage and development rates of oocytes after insemination with double straws from a single lot. These results indicate that the developmental capacity of embryos after insemination are affected by factors associated with a different semen lot from the same bull and with different straws from a single lot.