Conservation and utilization of yak genetic resources in Qinghai-Tibet plateau: problems and perspectives

Yak is the livestock indispensable for people′s production and life in Qinghai-Tibetan plateau. It is of irreplaceable significance to regional social development. And more critically, as a key species in the Qinghai-Tibet plateau ecosystem, the importance of yak to the ecological civilization construction on the Qinghai-Tibet plateau should not been neglected. In recent years, with the increased number of domestic yaks raised by herdsmen, grassland degradation is gradually aggravated and the production performance of yaks is gradually declined in Qinghai-Tibetan plateau. This phenomenon breaks the normal circulation of soil, grass and animal and destroys the herbage-animal balance, which has a strong impact on the stable and harmonic development of ecological system in Qinghai-Tibet plateau. However, identification and classification of Chinese yak genetic resources are still not completed, and it is still to be studied that why the production performance of yak is declined continuously and how to carry out the purification and rejuvenation work. In this paper, we payed attention to the effect of plateau ecological environment on yak distribution area and quantity change, classification of yak breeds under different geographical conditions, current status of yak breed degradation, strategy and effectiveness of breed improvement. Moreover, we discussed advances in genomic research of Chinese yak genetic resources in recent years, to clarify the genomic regulatory mechanism of physiological characteristics of yak. Furthermore, we also put forward our opinions about problems and perspectives in protection and utilization of Chinese yak genetic resources. In future research, we should evaluate the current situation of grazing management scientifically, establish the protection and utilization system of yak genetic resources, optimize livestock structure and control livestock amount, formulate scientific production management measures, illuminate the function of yak in maintaining the stability of grassland ecosystem, synthesize productive and ecological function of grassland resources to achieve the herbage-animal balance. This review provides important reference for scientific research and production practice of yak in the future.