Evaluation of activation treatments for blastocyst production and birth of viable calves following bovine intracytoplasmic sperm injection

The highest cleavage and blastocyst production rates were observed in the ionomycin + DMAP treatment (83.9% and 40.1%) by the ICSI. These rates were significantly (P < 0.05) higher than those for the ionomycin oocyte activation treatment (57.6% and 18.2%) but did not differ from the ethanol treatment (75.6% and 29.4%). In the sham-injected, the highest blastocyst production rates were observed for the ionomycin + DMAP and ethanol treatments (10.7% and 11.3%). Pregnancy and birth rates for blastocysts derived from the ethanol oocyte activation treatment (58.8% and 47.4%) were significantly higher (P < 0.05) than those of the ionomycin + DMAP treatment (12.5% and 9.2%). The results showed that post-ICSI oocyte activation with ethanol is more effective than activation with ionomycin alone or with ionomycin + DMAP for the production of viable blastocysts and calves.