1. College of Animal Science and Veterinary Medicine Shandong Agricultural University Tai'an City Shandong Province China
2. Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention Shandong Agricultural University Tai'an City Shandong Province China
3. Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention Shandong Agricultural University Tai'an City Shandong Province China