Washington

The US Department of Agriculture (USDA) is facing growing pressure from Congress to overhaul its surveillance regime for mad cow disease.

A powerful congressional committee says that the agriculture secretary, Ann Veneman, gave the public wrong information about the first mad cow found in the United States in December. Veneman said at the time that the cow had been targeted for testing because it was a ‘downer’ — an animal that arrived at the slaughterhouse too sick to walk (see Nature 427, 5; 200410.1038/427005b).

But two employees at the slaughterhouse in Washington state where the animal was killed, and the hauler who took the cow there, have all told congressional investigators that the cow wasn't a downer at all. The revelation seems to undermine Veneman's assertion that the department's existing focus on testing obviously sick animals was vindicated by the cow's detection.

In an unusual bipartisan move, the top Republican and the senior Democrat on the House Committee on Government Reform wrote to Veneman on 18 February, urging her to resolve the issue.

According to the letter, the co-manager of the slaughterhouse faxed a USDA office on 6 January to state that the mad cow was not a downer. He said that the animal was healthy, and had been tested under a contract whereby the USDA paid the slaughterhouse $10 per cow for test samples.

The revelations could force the agriculture department to change its current plan to test just 40,000 cows for mad cow disease this year. “If the new information is accurate, USDA's surveillance programme may need to be significantly expanded,” wrote congressmen Tom Davis (Republican, Virginia) and Henry Waxman (Democrat, California) in their letter. “The new information also raises questions about USDA's credibility.”

Earlier this month, an international review team chaired by Ulrich Kihm, Switzerland's chief veterinary officer, recommended that the USDA expand its programme to test all cows over 30 months old as well as some younger, healthy animals (see Nature 427, 575; 200410.1038/427575a). In their letter, the congressmen agreed: “We believe USDA should either follow the recommendations of these independent experts and expand mad cow testing substantially or provide a compelling reason for not doing so,” they wrote.

And while the agriculture department seemed reluctant to accept that advice at first, its position appears to be becoming more flexible. “Everything is in flux right now,” says Jim Rogers, a spokesman for the USDA's Animal and Plant Health Inspection Service. “Last I heard we were on target for testing 40,000 animals a year, but that could change, for sure.”

Rogers says that the agriculture department is also trying to figure out how to find and test downed animals, now that they are excluded from the food supply and will no longer be tested at slaughterhouses. He added that the department's inspector general would investigate the allegations that the first mad cow was not actually a downer.