1. Department of Applied Life Science, Nippon Veterinary and Life Science University, Tokyo 180-8602, Japan
2. Present: Division of Animal Reproduction, Maebashi Institute of Animal Science, Livestock Improvement Association of Japan (LIAJ), Gunma 371-0121, Japan
3. Niigata Agricultural Research Institute, Niigata 955-0143, Japan
4. Ishikawa Livestock Research Center, Ishikawa 929-1325, Japan
5. Kanagawa Prefectural Livestock Industry Technology Center, Kanagawa 243-0417, Japan
6. Department of Veterinary Medicine, Nippon Veterinary and Life Science University, Tokyo 180-8602, Japan
7. Animal Breeding and Reproduction Research Division, NARO Institute of Livestock and Grassland Science, Ibaraki 305-0901, Japan