The number of cattle tested for mad cow disease has fallen almost 90 percent since 2005, according to U.S. Agriculture Department statistics, a drop that consumer groups say endangers America’s food supply.
U.S. Agriculture Secretary Tom Vilsack yesterday said that animal testing is adequate, a day after his department confirmed the nation’s first known case of mad cow disease in six years, a dead dairy animal on its way to a rendering plant in central California.
About 40,000 cattle were tested in the year ended Sept. 30, down from 399,575 in 2005, according to USDA data. The drop-off followed a surge in testing conducted to establish the prevalence of the disease as the agency was trying to understand the risk and create a long-term monitoring system, John Clifford, the USDA’s chief veterinarian, said in an interview.
He said testing is only one component of the agency’s strategy to combat mad cow disease, which includes limiting the consumption of certain parts of cattle and restricting the content of their feed. Chris Waldrop, director of the Food Policy Institute of the Consumer Federation of America, a Washington-based safety advocacy group, said the testing decline means the U.S. is relying too much on other safeguards, which aren’t foolproof.
Need for Firewalls
“If you’re not going to test as much, your firewalls better be perfect, and there are loopholes in the firewalls,” Waldrop said. “After going so long without having a case in the U.S., and now we have one, it warrants another look at the surveillance program and ramping it up, at least temporarily, to see if there is something new going on.”
USDA investigations typically include tests of animals that were in the same herd as the diseased cow, as well as feed the animal may have consumed, Clifford said. Even when an animal tests positive for a form of BSE not connected to feed, as in this case, the investigative procedures are the same, he said. Any offsrping of the infected animal are also checked.
The USDA has not yet publicly identified the farm where the animal came from, or if the cow had any calves. Clifford would not comment on the current investigation.
The new case won’t spur more tests, as one case of the disease, known as bovine spongiform encephalopathy, in six years doesn’t necessarily indicate increased BSE prevalence, Clifford said.
The 2004 surge in testing was “an effort to collect as many samples as we could over 12 to 18 months to determine prevalence in the U.S.,” Clifford said. “After that, we went to a regular surveillance level that far exceeds international standards.”
The surveillance tests focus on older cattle and animals that may be exhibiting symptoms of the brain-wasting disease, he said.
About 40,000 animals are sampled each year, less than 0.1 percent of the U.S. cattle herd, according to USDA records.
Testing has fluctuated in recent months, from 2,434 samples in April 2012, down from 4,855 in March and 5,417 in February, according to the USDA.
Analysis of the 2004 to 2006 data concluded the prevalence of BSE in the U.S. is less than 1 case per million adult cattle, according to the agency. As of Jan. 1, the country’s herd of cattle and calves totaled 90.8 million animals, according to the USDA.
More testing isn’t necessary now that the USDA has a handle on the extent of the disease, said Eric Mittenthal, a spokesman with the American Meat Institute, a trade group based in Washington that includes Tyson Foods Inc. and Cargill Inc. among its members.
“Some critics have argued that every animal needs to be tested,” Mittenthal said in an e-mail. “That’s like saying that kindergarteners should be tested for Alzheimer’s,” he said. “USDA appropriately focuses its surveillance on older animals and animals that are displaying clinical signs of the disease,” he said.
Still, random tests aren’t enough to ensure that diseased cows don’t taint the food supply, Michael Hansen, a staff scientist at the nonprofit Consumers Union of Yonkers, New York, said yesterday.
U.S. testing “is very consistent with international standards and we want to make sure we abide by those international standards,” the USDA’s Vilsack said.
Jim Cullor, a professor of infectious disease in the School of Veterinary Medicine at the University of California at Davis, said the discovery of the latest case shows the U.S. surveillance system is effective.
In addition to the monitoring tests, the USDA protects the food supply by prohibiting parts from other cows and related animals to be used in cattle feed. Scientists say the disease is spread by cattle eating rations that contain tissue from infected animals. Since the first case in 2003, the agency has also required slaughterhouses to remove and dispose of certain “risk materials,” such as spinal cord and nerve tissue, to keep it from human consumption.
No Food Threat
Officials said the infected animal found recently at a Baker Commodities Inc. facility in Hanford, California, never entered the human food chain, and that the disease isn’t spread through milk. Tests indicate the animal had atypical BSE, a form not normally associated with infected feed.
A nationwide animal identification program that can track animals to their source is also necessary to ensure that threats are quickly handled, U.S. Representative Rosa DeLauro, a Connecticut Democrat, said in a statement.
“We were lucky to identify this case,” DeLauro said, “but we must invest in a strong national identification system that has the potential to improve animal traceability and ensure the health of our domestic livestock.”
Vilsack yesterday said a new rule on animal identification should be released “very, very soon.”
A nationwide animal identification system that would let officials track sick livestock back to their farms of origin -- and help identify other infected animals -- has been promised by the Department of Agriculture since 2003, after the first U.S. BSE case surfaced, in a cow born in Canada.
A voluntary animal ID plan was abandoned in 2010 after some ranchers refused to participate, citing cost and concerns that the proposed registry would give competitors proprietary information.
The rule Vilsack referred to, which the USDA proposed in August, would require registration and tagging of livestock moved between states, with guidelines tailored to different species. It would be put in place gradually, applying first to older animals in the U.S. cattle herd.