1. College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
2. National Beef Cattle Improvement Center, Northwest A&F University, Yangling, Shaanxi, China
3. Department of Livestock Management, the University of Agriculture, Peshawar, Pakistan
4. Longri Breeding Farm of Sichuan Province, Sichuan, Chengdu, China
5. Qinghai Academy of Animal Science and Veterinary Medicine, Qinghai University, Qinghai, Xining, China