The Time of Ovulation in Cattle

Abstract

Observations were made at 73 estrual periods of 47 cows of beef and dairy breeds. The time from the end of estrus to ovulation was determined by rectal palpations of the ovaries. Ovulation occurred within the first day after the end of estrus, the average time from the end of estrus to ovulation for 53 ovulations being 13.57 ± 0.68 hours. Sixty-seven per cent of the ovulations occurred between 8 and 16 hours after the end of estrus. Time of day and breed or type of animal had no influence on the time of ovulation. Both ovaries produced follicles with equal frequency. Heifers required an average of 3.04 hours less time to ovulate than cows that had calved. © 1941, American Dairy Science Association. All rights reserved.