1. Animal Physiology Research Unit, National Institute of Agrobiological Sciences, 2, Ikenodai, Tsukuba, Ibaraki 305–8602, Japan
2. Department of Animal Science, Tokai University, Kawayu, Minamiaso, Aso-gun, Kumamoto 869–1404, Japan
3. Animal Physiology and Nutrition Research Division, National Institute of Livestock and Grassland Science, 2, Ikenodai, Tsukuba, Ibaraki 305–0901, Japan
4. Livestock Production and Wildlife Management Research Division, NARO Western Region Agricultural Research Center, 60 Yoshinaga, Ooda-shi, Shimane 694–0013, Japan