All chemicals were obtained from Sigma-Aldrich Laboratory (St. Louis, MO, USA) unless otherwise
stated. Oocytes from Nelore and Holstein cows were divided into two treatment groups. In group 1, oocytes
of both breeds were aspirated 4 h after acquisition of ovaries in the abattoir, whereas in group 2, oocytes of
both breeds were aspirated 6.5 h after ovaries were acquired (the interval from death to ovary acquisition
was approximately 30 min). Nelore oocytes were fertilized with frozen-thawed semen from Nelore bulls,
whereas Holstein oocytes were fertilized with semen from Gir and Holstein bulls. Six bulls from each of the
three breeds were used.