1. Laboratory of Theriogenology, Faculty of Agriculture, Gifu University, Gifu 501-1193, Japan
2. Minnesota Department of Natural Resources, Forest Wildlife Populations and Research Group, Grand Rapids, MN 55744, U.S.A.
3. Carle Foundation, Department of Internal Medicine, University of Illinois, Urbana, IL 61801 U.S.A.
4. Animal Sciences Laboratory, University of Illinois, Urbana, IL 61801, U.S.A.