Abstract: [Objective] To explore the key factors affecting the fertility of dairy cows, to ensure the effective transmission of good traits and to improve the overall reproductive efficiency. [Method] Reproduction data from a large-scale dairy farm were collected and analysed to systematically assess the effects of month of breeding, cumulative litter size and quality of uterine repair on conception rate. [Result] The conception rate of cows in January, September, October and December was significantly higher than that of other months, while July and August showed lower conception rates, with significant differences （P<0.05） between these months. Further analyses showed that first time cows （1 lactation） had higher conception rate compared to multiple lactation cows, which was significantly different （P<0.05）. In addition, the state of uterine repair after parturition had a significant effect on conception rate, with cows with a well repaired uterus free of sepsis showing a higher conception rate. [Conclusion] In the process of cow breeding, reasonable selection of breeding month, priority selection of cows with appropriate litter size, and attention to post-partum uterine repair management are crucial to promote the selection and inheritance of excellent traits and improve the overall reproductive efficiency of dairy cattle populations.

Key words: dairy cow, lactation, parity, conception rate