The Agriculture Department (search) began expanded national testing for mad cow disease (search) Tuesday, intending to test about 220,000 animals for the brain-wasting condition over the next year to 18 months.

Officials said the department was able to handle the first day's samples even though most of the dozen regional laboratories aren't yet equipped to perform the initial tests.

The government last year conducted mad cow tests on tissues from 20,543 animals, virtually all of them cattle that could not stand or walk and had to be dragged to slaughter. After the nation's first case of the disease in December, the department initially doubled the number of animals to be tested this year to 40,000.

With many foreign governments still reluctant to ease bans on U.S. beef, the testing program was expanded at a cost of $70 million to include as many as 220,000 slaughtered animals, following recommendations from an international scientific review panel. About 35 million head of cattle are slaughtered each year in the United States.

The overwhelming majority of tests will be on animals considered most likely have mad cow — those showing any sign of brain disorder, unable to stand on their own or deemed unfit for human consumption for other reasons. Tissue samples from those animals would be tested, as would samples from animals that die on farms.

The department's testing plans also include about 20,000 animals that appear healthy but are at least 30 months old, the age at which mad cow disease appears.

The 12 state-operated labs around the country will perform the initial tests on brain and central nervous system tissue from slaughtered cattle for mad cow disease, also known as bovine spongiform encephalopathy (search), or BSE. Results from those tests will be returned in 24 to 72 hours.

If that rapid-response test indicates the animal may have BSE, tissue samples will then be sent to the department's National Veterinary Services Laboratory in Ames, Iowa, for confirmatory testing that could take four to eight days.

Seven of the rapid-test labs are able to handle large batches of tests, at least 1,000 per month, but only five of these were operating on the first day, department spokeswoman Andrea McNally said Tuesday.

The other two had "last-minute problems," she said. Five other labs, which would handle smaller batches, were not testing samples Tuesday but are scheduled to begin the work later, she said.

The five working labs are "more than sufficient" to handle the initial testing load, McNally said.

The department expects some rapid tests to indicate BSE, although that does not necessarily mean the animal has the disease, said Dr. Ron DeHaven, administrator of the department's Animal and Plant Health Inspection Service.