Abstract: As a unique and rare livestock species in the pastoral regions of the Qinghai-Tibet Plateau,yaks not only have important meat and milk value,but also serve as the core source of livelihood for plateau herders.Their reproductive performance is directly related to the economic efficiency of animal husbandry in pastoral areas and also has an important impact on the sustainable development of this industry. The reproductive process of yaks is regulated by various factors such as environment,nutrition and heredity. Among them,the extreme plateau environment and the seasonal fluctuation of nutritional supply interact with each other, forming a stress effect that most obviously restricts the reproductive performance of yaks.This study systematically sorted out the interaction mechanisms between key nutrients such as energy and protein and extreme plateau environmental factors such as hypoxia, low temperature and seasonal changes,analyzed in detail the specific roles of the two in various reproductive links of yaks,including estrus initiation, follicular development,ovulation quality,conception success rate, pregnancy maintenance and calf survival,deeply explores the internal physiological and molecular regulatory pathways such as the integrated regulation of the hypothalamic-pituitary-gonadal （HPG） axis,oxidative stress response, epigenetic modification and gut microbiota mediation,and summarized and put forward practical regulatory strategies such as seasonal precision nutrition supplementation,environmental stress alleviation,integrated reproductive technologies and optimized genetic selection,hoping to provide scientific theoretical basis and practical technical reference for the optimization and improvement of yak reproductive performance and the high-quality development of animal husbandry in pastoral areas.

Key words: yak, reproductive performance, nutritional regulation, environment interaction, plateau stress, regulatory mechanism, gut microbiota, epigenetics