Abstract: Heat stress caused by high temperatures in summer is a key challenge restricting the profitability of dairy farming. It not only reduces milk yield but also significantly impairs the reproductive performance of dairy cows. This paper systematically reviewed the mechanisms by which heat stress damages the physiological functions,endocrine homeostasis,and reproductive performance of dairy cows,with a focus on analyzing the negative effects of high-temperature environments on estrus expression,follicular development,early embryonic survival,and pregnancy success rates. Combined with field trial data,this paper elaborates on the application effects of the novel gonadotropin-releasing hormone （GnRH）analogue buserelin in scenarios such as fixed-time artificial insemination synchronization,reducing early embryonic mortality,and treating ovarian cysts. The study confirmed that buserelin can significantly alleviate heat stress-induced reproductive damage,improve summer conception rates,and enhance overall reproductive efficiency in dairy cows by regulating the endocrine status,increasing progesterone concentrations,and improving oocyte quality and the uterine environment. This provided a scientifically based practical solution for reproductive management in large-scale farms during summer.

Key words: heat stress, buserelin, early embryonic mortality, fixed-time artificial insemination synchronization, reproductive efficiency