1. Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Sciences, Ji’nan, P.R. China;
2. Shandong Key Lab of Animal Disease Control and Breeding, Shandong Provincial Testing Center of Beef Cattle Performance, Shandong Provincial Engineering Technology Center of Animal Healthy Breeding, Ji’nan, P.R. China;
3. College of Life Sciences, Shandong Normal University, Ji’nan, P.R. China