1. Key Laboratory of Animal Genetics and Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, Institute of Animal Science, Chinese Academy of Agricultural Sciences , Beijing 100193 , China
2. College of Animal Science and Technology, Yangzhou University , Yangzhou 225009 , China
3. Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University , Yangzhou 225009 , China
4. Jilin Provincial Key Laboratory of Grassland Farming, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences , Changchun 130102 , China