Variation in gestation length as breeding season advances in Bruna dels Pirineus beef cattle breed

Abstract

The variation in gestation length according to the time lapse from the onset of the breeding season until the day of mating was investigated in the Bruna dels Pirineus beef cattle breed. A total of 359 gestations belonging to five breeding seasons were analysed. Average gestation length under natural service was 288.6. Gestation length tended to increase significantly (p < 0.05) to about 1.5 days in cows that were mounted in the two last thirds of the breeding season. The effects of domestication on birth synchrony are discussed.