1. College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, 712100, P.R. China
2. State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, Qinghai Province 810016, People’s Republic of China
3. Animal Science, School of Agriculture and Environment, Massey University, 4442 Palmerston North, New Zealand
4. National Beef Cattle Improvement Center, Northwest A&F University, Yangling, 712100 Shaanxi, P.R. China