1. Laboratory of Animal Science, Graduate School for International Development and Cooperation, Hiroshima University, 1-5-1 Kagamiyama, Higashi-Hiroshima 739-8529, Japan
2. Department of Theriogenology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia 41522, Egypt
3. Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Ueda 3-18-8, Morioka 020-8550, Japan
4. Oasa-Takamachi 25-12, Ebetsu, Hokkaido 069-0853, Japan
5. Field Center for Sustainable Agriculture and Forestry, Faculty of Agriculture, Niigata University, Niigata 950-2181, Japan