1. Department of Theriogenology, College of Veterinary Medicine, Seoul National University, Seoul 151-742
2. Department of Veterinary Medicine, Kangwon National University, Chunchon 200-701
3. College of Medicine, Pochon CHA University, Infertility Medical Center of CHA General Hospital, Seoul 135-081, Korea
4. Department of Animal Life and Resources, Hankyong National University, Ansung 456-749, Korea
5. Department of Veterinary Physiology & Pharmacology, College of Veterinary Medicine, Texas A&M University, College Station, Texas 77843-4466, U.S.A.
6. Department of Theriogenology, College of Veterinary Medicine, Chungbuk National University, Cheongju 361-763, Korea