A special law requiring nationwide testing of dead cattle for mad cow disease went into force Tuesday, but more than a third of prefectural governments failed to comply, citing a lack of manpower and facilities.

The examinations of cows aged 2 or older that have either been slaughtered or died of apparent natural causes are part of efforts to combat the disease also known as bovine spongiform encephalopathy.

But according to the farm ministry, 16 prefectural governments did not begin testing due to an insufficient number of veterinarians and facilities to test the large number of cows subject to the inspections.

Those prefectural governments will eventually conduct the tests, the ministry claimed, adding that the dead cows are not put on the market for food purposes.

The national government already has an inspection program in place to test for mad cow disease in slaughtered cattle destined to become food.

The prefectures that failed to begin testing for the brain-wasting disease are Hokkaido, Nagano, Hiroshima, Kagoshima, Aomori, Niigata, Gifu, Aichi, Shimane, Okayama, Yamaguchi, Fukuoka, Nagasaki, Kumamoto, Miyazaki and Okinawa.

Six dairy cows in Japan have so far been confirmed to have been infected with mad cow disease since September 2001. One cow raised for beef is also suspected of being infected with the disease.