1. Key Laboratory for Animal Genetics, Breeding, Reproduction and Molecular Design of Jiangsu Province, College of Animal Science and Technology, Yangzhou University , Yangzhou 225009 , P R China
2. Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University , Yangzhou 225009 , China
3. Department of Animal Science, Laval University , Quebec, Quebec, G1V0A6 , Canada
4. Center for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph , Guelph, ON, N1G2W1 , Canada