The nation’s fourth confirmed case of bovine spongiform encephalopathy (BSE) infected a 10-year, 7-month-old dairy cow on a dairy farm in California’s Tulare County.
USDA said the animal “was humanely euthanized after it developed lameness and became recumbent.” In other words, the dairy cow was demonstrating “downer” cow behavior often associated with BSE.
“It is important to reiterate that this animal was never presented for slaughter for human consumption, did not enter food supply channels, and at no time presented any risk to human health,” USDA said in a news release Thursday.
USDA also acknowledged some timeline changes surrounding discovery of the BSE-infected dairy cow.
Most significantly, the department said there was a four-day span between the bovine brain sample arriving at the National Veterinary Services Laboratories (NVSL) in Iowa on April 20 and USDA’s Animal and Plant Health Inspection Service (APHIS) announcing the BSE positive test on April 24.
The infected cow was killed and its carcass picked up on or about April 18 by Baker Commodities, a Los Angeles-based company that owns and operates a rendering transfer station at Hanford in neighboring Kings County, CA.
Test results on a initial brain tissue sample sent to the University of California, Davis were inconclusive on April 19, and the sample was delivered to the Iowa lab the next day.
USDA has not said exactly when NVSL knew the California dairy cow was positive for BSE, but some traders blame mad cow rumors for roiling the cattle markets early in the week before the formal announcement settled things down.
The diseased carcass, along with all other dead cows that arrived with it on the same truck, are being held in cold storage by Baker. The diseased cow, according to USDA, never came anywhere close to being used for human or pet food.
A USDA-led epidemiological investigation is continuing with a focus on Tulare County’s dairy herds. The diseased cow’s calves and other cows born around the same time are coming in for attention.
On the same day it promised to make the findings of its investigation public in a
“in a timely and transparent manner,” USDA also gave the new media a bit of a lecture. Courtney Rowe, USDA’s press secretary, in a rare memo to news organizations, said there have been “an unfortunate amount of misleading articles” on the BSE incident.
“The fact is, a stringent feed ban, the removal of all central nervous tissues during slaughter, and our BSE surveillance tests all work in concert to protect Americans and our food,” Rowe said. “And they do work—very well.”
“Yet, some have chosen to focus on the number of tests–a number which is 10 times greater than what is required under international standards–rather than the real story: That the United States has one of the most successful and effective BSE-prevention programs in the world, helping to ensure the safety of our food for millions of consumers every day, ” Rowe added.
John Clifford, USDA’s chief veterinary officer, has spent much of his week explaining the “interlocking” defenses the U.S. has erected against mad cow disease, including the way it risk-based testing program.
“We take samples from approximately 40,000 animals each year, focusing on groups where the disease is more likely to be found. The targeted population for ongoing surveillance includes cattle exhibiting signs of central nervous disorders or signs associated with BSE, non-ambulatory animals, and dead cattle,” Clifford said. “The samples come from locations like farms, veterinary diagnostic laboratories, public health laboratories, slaughter facilities, veterinary clinics, and livestock markets.”
Thus, the sample taken from a cow that had to be put down after showing “downer” symptoms and was then picked up by a rendering company was exactly what the program targets.
Milk does not transmit BSE, according to scientific research reviewed by the World Health Organization (WHO).
“Our investigation is ongoing,” Clifford said. “But here are a few things we do know for a fact. It is perfectly safe to eat beef and drink milk without concern for BSE.”© Food Safety News