1. Laboratory of Large Animal Clinical Sciences, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
2. Kanagawa Prefecture Government, 1 Nihon ohdouri, Naka-ku, Yokohama, Kanagawa 231-8588, Japan
3. Hokkaido Dairy Management Service, 5-9 Shimosetsuri, Tsurui, Akan-gun, Hokkaido 085-1211, Japan
4. Laboratory of Theriogenology, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan