1. College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, Gansu, China
2. The State Key Laboratory of Grassland Agroecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, Gansu, China
3. Institute of Animal Science, Xinjiang Academy of Animal Sciences, Urumqi, Xinjiang, China
4. Institute of Animal Husbandry Quality Standards, Xinjiang Academy of Animal Sciences, Urumqi, Xinjiang, China