Abstract
In this study, we attempted the application of several biotechnology techniques to the Kuchinoshima wild cattle, endangered Japanese cattle.
On a result of measurement of their shapes, it was rather small in stature than that of Japanese black. Five Kuchinoshima wild cattle, four Japanese black and two F1 (Holstein × Japanese black) cattle were inseminated artificially by using frozen-thawed epididymal spermatozoa of wild cattle which had been cryopreserved by standard technique in a liquid nitrogen (LN2) . Seven out of 11 cows (including 3 wild cattle) became pregnant. When in vitro matured oocytes collected from Japanese black were fertilized with frozen-thawed epididymal spermatozoa of wild cattle, 69.3% (296/427) oocytes cleaved and 25.8% (110/427) of them developed to blastocysts. Embryo collections were conducted on three superovulated wild cattle which were inseminated with frozen-thawed ejaculated spermatozoa of Japanese black, but only one of them produced transferable embryos. Embryo transfers were conducted on 3 recipient cows and one of them became pregnant.
