An Alabama cow infected with bovine spongiform encephalopathy (BSE) or “mad cow disease” has been exhumed so investigators can more accurately determine its age, according to state officials. The BSE case was confirmed in mid-March.
Federal and state agriculture workers excavated the remains of the animal, which had been buried on the farm and did not enter the animal or human food chain, in accordance with USDA protocols. The carcass was that of a red crossbred beef type cow.
An examination of the cow's teeth confirmed that the animal was at least 10 years of age. Samples were taken of the animal and the remaining carcass was transported to one of the department's diagnostic labs for proper disposal. State and Federal staff are continuing the traceback to determine the herd of origin.
One calf has been identified by the owner as belonging to the red cow. The calf is approximately six weeks old and appeared to be a healthy animal. The calf was transported to a USDA lab where DNA from the calf will be compared to that of the red cow to confirm relation. If confirmed, this would be the first offspring of a BSE diagnosed cow in the United States. Officials have learned that in early 2005, the BSE-positive cow gave birth to another black bull calf. That animal is in the process of being traced.
“I was very concerned to find out that the samples which tested positive for BSE were from a cow in Alabama, but this is exactly the reason that we emphasis the importance of BSE surveillance,” says Alabama Agriculture & Industry Commissioner Ron Sparks. “The cow was tested as part of the enhanced BSE surveillance program that has been in place in Alabama.”
Even cows brought in from other states are tested for BSE before they would have a chance to be sold as food, says Sparks. “I cannot stress enough how important this testing is to protect consumers. Also, having the Premises ID program in place in Alabama means we are able to trace the origin of a diseased animal. The cattle producers of Alabama understand the need for these precautions as well, and we will continue to work together closely to protect consumers.”
The cow had been purchased by an Alabama producer and was examined and treated by a local veterinarian. After failing to respond to medication, the cow was humanely euthanized by the veterinarian and a routine sample was collected to test for BSE.
Following an inconclusive test result from a rapid BSE test, the samples were tested at the National Veterinary Services Laboratories in Ames, Iowa. The Western blot test produced a positive result. A third test, the immunohistochemistry test, is ongoing.
BSE is not a contagious disease that spreads animal to animal, or animal to human.
BSE spreads in cattle through feed containing meat and bone meal derived from BSE infected cattle. The United States banned the use of such protein supplements in cattle feed since 1997.
Sparks stresses that beef consumption in this country is safe and there are measures in place to see that they continue. For example, downer animals are not allowed to enter commerce for human consumption and there is a ban on feeding ruminant derived protein to cattle.
It is the policy of the Alabama Department of Agriculture & Industries and the USDA not to disclose the location of the farm where the animal was located, says Sparks.
“We consider that information to be private. USDA does not release that kind of information for BSE or for any other disease program. The producer and other producers around the country are helping us with our enhanced BSE surveillance program and protecting their privacy encourages them to do so.
“This producer did exactly what he should have under the system. We want that cooperation to continue and bringing unnecessary hardship and attention to them would not benefit the consumers or farmers. This program is working and there is no danger to the existing herd because this disease is not contagious,” says the commissioner.
USDA officials were working with those in Alabama to conduct an epidemiological investigation, says USDA Chief Veterinary Officer John Clifford. “We will be working to locate animals from this cow's birth cohort (animals born in the same herd within one year of the affected animal) and any offspring.”
“We will also work with Food and Drug Administration officials to determine any feed history that may be relevant to the investigation. Experience worldwide has shown us it is highly unusual to find BSE in more than one animal in a herd or in an affected animal's offspring. Nevertheless, all animals of interest will be tested for BSE,” says Clifford.
“The age of this animal would indicate that it would have been born prior to the implementation of the Food and Drug Administration's 1997 feed ban. Older animals are more likely to have been exposed to contaminated feed circulating before the FDA's 1997 ban on ruminant-to-ruminant feeding practices, which scientific research has indicated is the most likely route for BSE transmission,” he says.
Incidence is low
By any measure, the incidence of BSE in this country is extremely low, says Clifford. “Our enhanced surveillance program was designed as a one-time snapshot to provide information about the level of prevalence of BSE in the United States. We have conducted surveillance in the United States since 1990 and following the initial positive in December 2003, we developed an enhanced surveillance program.
“Since June 2004, all sectors of the cattle industry have cooperated in this program by submitting samples from more than 640,000 animals from the highest risk populations and more than 20,000 from clinically normal, older animals, as part of our enhanced BSE surveillance program. To date, including the animal in Alabama, only two of these highest risk animals have tested positive for the disease as part of the enhanced surveillance program,” he says.
The Alabama case is the third BSE case confirmed in the United States. The first was found in a Canadian-born cow in Washington state in December 2003, and then this past June in a Texas cow. The problem prompted some countries, including Japan, to temporarily cut off beef exports.
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