1. Laboratory of Theriogenology; Department of Applied Veterinary Medicine; Obihiro University of Agriculture and Veterinary Medicine; Obihiro Hokkaido Japan
2. The United Graduate School of Veterinary Sciences; Gifu University; Gifu Japan
3. Laboratory of Veterinary Anatomy; Department of Basic Veterinary Medicine; Obihiro University of Agriculture and Veterinary Medicine; Obihiro Hokkaido Japan
4. Noboribetsu Bear Park; Noboribetsu Hokkaido Japan