Fig 1. Geographic regions of the national breeding stock farms in South Korea.

Blood samples were obtained from cattle at 17 national breeding stock farms from four different regions in Korea. The four regions were the following: Northern [Gyeonggi (GG) and Gangwon (GW)]; Central [Chungbuk (CB), Chungnam (CN), and Gyeongbuk (GB)]; Southern [Jeonbuk (JB), Jeonnam (JN), and Gyeongnam (GN)]; and Jeju Island. The location of the 17 national breeding stock farms are denoted by dots.