1. College of Patacultural Science, Gansu Agricultural University; Key Laboratory of Grassland Ecosystem, Ministry of Education; Sino-U.S. Center for Grazing land Ecosystem Sustainability; Pratacultural Engineering Laboratory of Gansu Province, Lanzhou, P. R. China
2. Qinghai Academy of Animal and Veterinary Science, Qinghai University, Xining, P. R. China