1. Department of Animal Husbandry and Fisheries, Guizhou Vocational College of Agriculture, Qingzhen 551400, China
2. Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
3. Qiandongnan Center for Animal Disease Control and Prevention, Kaili 556000, China