Evaluation of parity and its interaction effect with season of calving, period of calving on production and reproduction traits in Hardhenu (Bos taurus x Bos indicus) dairy cattle

This study investigated the impact of parity, period of calving, and season of calving on various production and reproduction traits in Hardhenu cattle. Third-parity cows outperformed first and second-parity cows, exhibiting significantly higher total milk yield (TMY), 305 days milk yield (305d MY), peak yield (PY), and artificial insemination per conception (AIPC) (p < .01). The Lactation length (LL) was inversely related to parity, with first-parity cows having extended lactations (p < .05). The period of calving had a substantial influence on production traits. The season of calving was critical, affecting production traits differently across parities. First-parity cows had the highest TMY and 305d MY during winter and summer calving, with summer calving associated with shorter LL (p < .05). Second-parity cows showed higher TMY and 305d MY during summer calving, while third-parity cows had higher TMY in winter (p < .01). PY followed similar patterns to TMY, with LL affected by the season of calving. Additionally, the study explored interactions between parity, period of calving, and season of calving on reproduction traits. Third-parity cows had higher AIPC compared to first and second-parity cows (p < .01). Reproduction traits were also significantly affected by the period of calving, with cows calving in the 2017-2021 period displaying longer service period (SP), calving interval (CI), dry period (DP), and AIPC (p < .01). These findings highlight the complex interplay of biological, environmental, and management factors in shaping the productivity and reproductive efficiency of Hardhenu cattle, emphasizing the need for multifaceted considerations to optimize herd performance.