摘要

<正>1.Introduction The Tibetan Autonomous Region(TAR) is located in the alpine region with an average altitude of 4000 m, AMSL. With vast area of 1.22 million square km dominated by rangelands, livestock farming has been the main source of livelihoods for the Tibetans. Yaks, cows, sheep and horses are important livestock species reared for their multiple services including food, energy, draught power and social security.