1. College of Animal Science and Technology, Northwest A&F University, Xianyang, People’s Republic of China
2. Henan Provincial Animal Husbandry General Station, Zhengzhou, People’s Republic of China
3. Guyuan Branch of Ningxia Academy of Agriculture and Forestry Sciences, Guyuan, People’s Republic of China
4. Institute of Animal Husbandry and Veterinary Science, Henan Academy of Agricultural Sciences, Zhengzhou, People's Republic of China