Influence of temperature-humidity index, calf sex, and parity on gestation length in Holstein cows

Abstract

The present study aimed to analyse the gestation length (GL) variability in locally born purebred Holstein dams (n = 1047), in a private farm, under Saharan climate. The overall GL mean was 278.73 ± 6.67 days. A general linear model revealed that the GL was significantly affected by calf sex (p = 0.035) with a minor increase of 0.19% in males, dam parity (p = 0.016) and calving season (p < 0.0001) including the shortest lengths recorded in heifers and during heat stress period. Moreover, a negative regression (-1.96%) in recent years was recorded in GL by the influence (p = 0.01) of years of birth, breeding, and calving of cows. Our findings show that cows that were inseminated and gave birth during the cold season (temperature-humidity index, THI < 74) had 11.54 days longer (p = 0.048) gestation period compared to animals that were inseminated and gave birth during the hot season (THI > 84). Similarly, the association (p = 0.003) between dam parity and calf sex revealed that the GL of multiparous cows that gave birth to male calves was higher (3.07 days) than that of male calves from heifers. The findings can contribute to a better understanding of the environmental and animal factors association's effects on GL in Holstein cows under hyperarid zone and assisting in the adequate management of pregnant females.