1. Usui Animal Hospital, 4–5 Midorino, Utsunomiya, Tochigi 321-0136, Japan
2. Nippon Veterinary and Life Science University, 1–7–1 Kyonan, Musashino, Tokyo 180-8602, Japan
3. Laboratory of Animal Breeding Reproduction, Faculty of Agriculture, Utsunomiya University, 350 Mine-machi, Utsunomiya 321-8505, Japan
4. Teikyo University Institute of Medical Mycology, 359 Otsuka, Hachioji, Tokyo 192-0395, Japan