1. College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, Gansu, China
2. The State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, Gansu, China
3. Engineering Laboratory of Sheep Breeding and Reproduction Biotechnology in Gansu Province, Minqin, China
4. Linze County Animal Disease Prevention and Control Center of Gansu Province, Linze, China