The U.S. Agriculture Department may need up to two weeks to determine if a suspect older animal was infected with mad cow disease, the department's chief veterinarian told Reuters on Saturday.

John Clifford, the USDA's top veterinarian, said tests will be carried out at the USDA laboratory in Ames, Iowa, and at an internationally known facility in Weybridge, England, to determine if the animal is infected.

Demonstrators dump calf feed that they say includes cow blood and slaughterhouse waste into a bin beside a sculpture of a cow at the St. Paul campus of the University of Minnesota, Thursday, June 9, 2005. Protesters disapprove of the U.S.' mad cow screening program and its regulations regarding the makeup of cattle feed. U.S. Agriculture Secretary Mike Johanns said during a a round-table discussion on the University of Minnesota's St. Paul campus, that his office believes the North American beef supply is safe and that full cattle trade with Canada should be restored. (AP Photo/Jim Mone)

The USDA reported late on Friday that an animal tested positive for the brain-wasting disease, reigniting fears that foreign countries would shun U.S. beef again.

The government said the suspect animal, first tested in November, did not enter the human food or livestock feed supply because it was unable to walk when delivered for slaughter.

The only confirmed U.S. case of bovine spongiform encephalopathy (BSE), or mad cow disease, was found in December 2003 in a Washington state dairy cow. The discovery halted billions of dollars worth of American beef exports.

Clifford said USDA scientists were drawing up a detailed testing plan for the suspect animal. A decision on exactly how many tests, and what types, was expected by late next week, he said.

"We want to make sure that everybody agrees on the tests that should be done," Clifford said in an interview.

A key first step, he said, is for the USDA to conduct additional analyzes on the animal's remaining brain sample to ensure that enough tissue was still available for testing in England. Only 12.5 grams (0.4 ounces) of the animal's brain remained, he said.

Several tests ranging in sophistication can determine mad cow disease, and some require a larger amount of brain tissue.

The USDA was mulling whether to wait and make only one announcement when all the tests were complete, a process that could take up to two weeks, Clifford said.

Clifford declined to say where the animal was slaughtered or give details about its sex or breed. "We are not ready to divulge that information," he said.

FOOD SAFETY CONCERNS

The senior Democrat on the House Appropriations subcommittee on agriculture, Rep. Rosa DeLauro of Connecticut, urged the USDA to implement stronger safeguards to protect consumers and cattle from mad cow disease.

"The possibility of a second case of mad cow in America raises concerns over the integrity of our cattle," she said in a statement.

USDA spokesman Ed Loyd said department scientists were already at work.

"We are running it through again to ensure the results," Loyd said. "We want to also ensure we send samples to Weybridge that are adequate enough for them to conduct appropriate testing that allows for a valid result."

Washington has informed all of its agricultural attaches with U.S. embassies around the world about the suspect animal.

"Certainly an important part of what we do over the next few days will be to keep all of our trading partners informed of our progress," Loyd said.

Agriculture Secretary Mike Johanns, who announced the possible mad cow disease on Friday evening, said the incident should not impact U.S. beef trade. Since becoming chief of the USDA earlier this year, Johanns has repeatedly said that his top priority is to restore American beef export trade.

USDA officials have been pressing for resumed purchases of American beef by Japan and South Korea, which suspended purchases in December 2003.

Before its ban, Japan was the No. 1 beef market for the United States, buying $1.4 billion annually. South Korea was its third-largest market.

The Japanese government agreed in principle in October to resume beef imports from American cattle aged 20 months or younger, but insisted shipments would not resume until its independent commission declared U.S. beef was safe to eat.

Current negotiations with South Korea center on beef from animals under 30 months.

The USDA said the suspect animal's brain tested positive for BSE in a rapid, preliminary test in November. When immediately retested with more sophisticated technology, it was found free of the disease.

But the USDA's inspector general asked scientists on Wednesday to retest the animal using a third kind of technology known as the "Western blot" test. The animal tested positive late on Friday.

The Western blot test was requested by a consumer group in February, which said it was the most definitive test available.

© 2005 Reuters) Ltd.

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