1. College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, Xinjiang Uygur Autonomous Region 830052, PR China.
2. Institute of Veterinary Medicine, Xinjiang Academy of Animal Sciences, Urumqi, Xinjiang Uygur Autonomous Region 830013, PR China.
3. College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, Shandong Province 266109, PR China.