Analysis of Variation in Some Factors Affecting Multiple Ovulations in Holstein Cattle

Summary A total of 790 parities (728 noncystic and 62 cystic) covering 3,549 ovulations was analyzed for effects of sire-line, system of mating, parity, cystic condition, and individuality of the cow on the incidence of multiple ovulations. Sire-line had no significant influence. Frequency of multiple ovulations increased in association with the cystic condition and with increasing parity. Outbreds had a significantly higher incidence of multiple ovulations than inbreds. A highly significant repeatability (0.07) within a cow also was noted.