The public should be prepared for more inconclusive BSE, or mad cow disease, reports because of expanded testing launched June 1 by the USDA.
David Smith and David Steffen, University of Nebraska veterinary scientists, say the larger sampling of animals in the USDA's expanded BSE surveillance testing will result in more inconclusive findings from initial rapid screening. As of Tuesday June 29, 8,585 cattle had been screened since June 1.
"Anytime you expand testing, you are bound to have more tests that are inconclusive," Smith says.
On June 25, USDA announced that an animal produced an inconclusive instead of negative result in initial screening for bovine spongiform encephalopathy, or BSE. Late on June 29, USDA announced a second inconclusive result from initial screening. In both instances, further tests are being conducted at USDA's National Veterinary Laboratory in Ames, Iowa.
Cattle futures prices fell sharply June 28 in response to the previous Friday's announcement, but rebounded somewhat on June 29.
Fed cattle prices dropped from $90 to $75 shortly after the nation's only confirmed case of BSE was detected in a dairy cow in Washington in late December, says Darrell Mark, a university livestock marketing specialist. Since then, prices have been rising steadily and are up 20% from early year lows.
"The industry was expecting approximately one inconclusive test per 10,000 samples, and after one month and slightly less than that number tested, having two inconclusive tests may indicate we'll see more of these than expected," Mark says. "This will increase market volatility and cause consumers to question the BSE surveillance program." But the surveillance program is working as it was designed to, he adds.
Smith says the public and the markets need to become accustomed to the testing process and the related announcements that will be forthcoming. After the December incident, the USDA was criticized for not disclosing the incident sooner.
Steffen adds, "If there is a false positive for every 1,000 tests, then the USDA could expect hundreds of false positive reports from the 200,000 tests to be conducted by next June. The public and the markets need to be prepared for that."
With the resulting drop in cattle futures prices, Mark says some people are asking why the USDA notified the public of the inconclusive results.
"Last time the USDA drew criticism for not announcing sooner," says Mark, who noted that full disclosure will benefit the beef industry if people understand the real issues behind the testing process.
"The press release from USDA about the (June 25) finding was very clear, but right away a few people started talking about it like it was a new confirmed case of BSE," he says.