A test conducted Saturday on a slaughtered cow has revealed that it was infected with mad cow disease, the health ministry said.
The case is the fourth to be confirmed since last September, when the first case of the disease was reported in Japan.
The outcome of Saturday's more precise test, carried out at the Obihiro University of Agriculture and Veterinary Medicine in Hokkaido, followed a preliminary test Friday, in which the 6-year-old Holstein initially tested positive for the brain-wasting illness.