1. Department of Theriogenology and Biotechnology; College of Veterinary Medicine and the Research Institute for Veterinary Science; Seoul National University; Seoul 151-742 Korea
2. Department of Physiology; Faculty of Veterinary Medicine; Zagazig University; Zagazig 44519 Egypt
3. Designed Animal and Transplantation; Institute of Green Bio Science Technology; Seoul National University; Pyeongchang 232-916 Korea