1. Key Laboratory of Microbiology & Immunology, College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot 010018, P.R. China.
2. School of Public Health, Baotou Medical College, Baotou 014040, P.R. China.
3. Companion Animal Genetics and Genomics, Inner Mongolia Agricultural University, Hohhot 010018, P.R. China.