WASHINGTON — The U.S. Department of Agriculture, responding to a critical report, defended its testing program for mad cow disease Tuesday, saying the surveillance plan that went into effect June 1 targets "precisely the population of animals we should be testing."
The draft report, prepared by the USDA's Office of Inspector General and released by Rep. Henry A. Waxman (D-Los Angeles), charges that the program has failed to test hundreds of cattle with symptoms indicating a central nervous system disorder -- a possible sign of bovine spongiform encephalopathy, or BSE, the scientific name for mad cow disease.
The report also said that the department had not cooperated with inspectors, had provided little documentation about the types of cows tested, and had failed to take into account that apparently healthy cattle could harbor BSE.
But Dr. Ron DeHaven, administrator of USDA's Animal and Plant Health Inspection Service, said in a conference call with reporters Tuesday that "if we want to find the disease, we should be biasing our testing toward this [high-risk] population."
He said that many of the inspector general's concerns reflected "a snapshot in time" of the surveillance program in March and that those problems had been addressed in the program that began last month.
The report, and the department's response, came on the eve of joint hearings today by the House Agriculture Committee and the House Government Reform Committee, where Waxman is the highest-ranking Democrat.
Agriculture Secretary Ann M. Veneman is expected to testify about the department's handling of the mad cow scare, which began when she announced Dec. 23 that a cow in Washington state had tested positive for BSE.
The announcement devastated U.S. exports, particularly to Japan, the top beef importer. A ban on U.S. beef and live cattle products continues in Japan, which has demanded that America test for mad cow disease all 35 million animals it slaughters annually.
BSE, a fatal brain-rotting disease, is believed to be caused by unusual proteins, called prions, that tend to concentrate in brain and nerve tissue. Only tests conducted after a cow's death can determine if the animal had BSE.
U.S. officials have maintained that U.S. cattle are free from BSE -- the infected cow identified had been imported from Canada -- and that a random sampling of cows, focusing on those that died before reaching the slaughterhouse, is statistically reliable in ferreting out the disease.
"Whenever you design a sampling program, you have to make certain assumptions," said Keith Collins, the USDA's chief economist. The department in this case assumed that BSE cases would probably be found in the high-risk population.
"The Office of Inspector General said we ought to look at that, and we are going to look at alternative approaches," Collins said. "This is not a settled issue."
DeHaven said he was "quite encouraged by the results of sampling" in June. Of the 11,000 animals tested, he said, about 70% were from the at-risk population that died before slaughter. The sampled cows came from a variety of collection points, from slaughterhouses to stockyards to rendering plants.
"A draft report is just that, a snapshot in time," he said. "We've recognized a lot of the shortcomings of the previous plan. The new plan reflects those changes."
He said the field staff had been instructed: "When in doubt, take a sample."