Yaks’ Body Condition And Nutritious Compositions Of Herbage In Different Seasons In Qinghai-tibet Plateau

As one of the main cattle of China, yaks mainly exist in Qinghai-Tibet plateau, northwest China. Compare to Tibet sheep, yaks make more influence to grassland because of the characteristics of bigger quantity of food taking, stronger tread action, and bigger quantity of excretion. Base on the importance of yaks grazing in agriculture system and biological property, it’s becoming the key solution to improve management of yaks grazing, which in order for protection of benefits for local people and protection of ecological in Qinghai-Tibet plateau. In this article, author investigated three herdsmen families in Azi station, Maqu county, Gansu province in order to find out the relationship between yaks’ body condition and nutritious compositions of herbage under different grazing intensities during May, 2015 to January, 2016. Research indicates:1.The body condition of livestock under different grazing intensities showed different characteristics, but the difference was not significant. Differences of yaks’ body condition mainly showed up in different seasons.2.Nutritive dynamic of natural grass is according to the rule of plant growth, but it differs under different stocking rates. Testing the nutrient content of edible forage in natural grassland founding that, the peak of crude protein and crude fat were both in August, however, the value of neutral detergent fiber and acid detergent fiber were the lowest. In warm season, grass began to turn green from May, crude protein and crude fat were increasing while neutral detergent fiber and acid detergent fiber were dropping. In cold season, the nutrition indicators of forage were stable and there was not difference from October to December.3.There was positive relationship between Yak’s body condition and aboveground biomass, crude protein, crude fat of edible grass, while, it was negative with neutral detergent fiber and acid detergent fiber.