The timing of activation treatment and the age of bovine oocytes affect cleavage and development rates after intracytoplasmic sperm injection (ICSI). Activating oocytes 2 or 4 hours after ICSI results in higher cleavage rates and blastocyst formation. Oocytes matured for 22-26 hours and activated with ethanol show better cleavage and blastocyst rates compared to non-activated oocytes. However, blastocyst rates decrease in oocytes matured for 30 hours despite activation treatment. Timing and age play crucial roles in the success of ICSI in bovine oocytes.