Jan 9, 2004 (CIDRAP News) The US Department of Agriculture (USDA) said today it will euthanize about 129 cattle in Washington state because of a risk that some of them were raised in Canada with the cow that was recently found to have bovine spongiform encephalopathy (BSE).
The cattle now are part of the 4,000-head "index herd" at Mabton, Wash., where the BSE-infected cow lived before it was shipped to a slaughterhouse, said Dr. Ron DeHaven, USDA's chief veterinary officer, at a briefing today.
DeHaven said investigators have been studying birth records on the cattle at Mabton and have narrowed the number of animals that might have been part of the infected cow's birth herd to 258. Of those 258, it appears that about 110 were previously removed from the Mabton herd, and USDA is trying to trace them. Of the remaining 148 cattle, 129 are still on the farm and are the ones now targeted for removal, he said. No records have been found on another 19 cattle, and investigators are trying to identify them.
The infected cow was one of 81 cattle from a herd in Alberta that were sold into Washington in September 2001, according to DeHaven. At least nine of those animals, and possibly more, are among the 129 cattle the USDA plans to remove, he indicated. Cows raised with the infected animal might have had the same feed source, raising the possibility that they could have BSE.
The 129 cattle will be the second group euthanized in the investigation and containment effort triggered by the discovery of the BSE-infected cow last month. A herd of 449 bull calves that included a calf born to the infected cow were euthanized in Wilbur, Wash., Jan 7, according to a report in the Yakima (Wash.) Herald-Republic. USDA officials said earlier this week that the whole herd had to be sacrificed as a precaution because the calf couldn't be identified.
The cattle from the Mabton herd will be euthanized at the same facility where the bull calves were sacrificed, DeHaven said. None of the animals will be used for food or animal feed, he added. The carcasses will be tested for BSE, and those that test negative will be dumped in a landfill. If any of them test positive, "We would seek one of the recognized means of disposing of carcasses, such as digestion in a chemical digestion tank or incineration," DeHaven said.
The bull calves that were destroyed Jan 7 were put in the Roosevelt Regional Landfill in Klickitat County, Wash., according to the Herald-Republic report.
DeHaven said the infected cow's birth herd in Alberta included a total of 112 head, all of which were sold in September 2001. Those that were not shipped to Washington went to various locations in Canada, and 17 of them might have been exported to the United States later, he said. "We have no hard evidence that any or all of those 17 came to the United States, nor can we rule that out," he said.
In other comments, DeHaven said the USDA is ready to accept applications for licensing of rapid BSE screening tests, which will be needed as the agency steps up its BSE surveillance. The agency has been using immunohistochemical staining, considered the "gold standard" test for BSE, but it can take up to 2 weeks from sample collection until test results are available, he said.
Officials previously expressed hope that rapid tests used in some countries could yield results in 36 to 48 hours. USDA has already been reviewing data on some of them, DeHaven said. The licensing process will include review of company data, inspection of test production facilities, and USDA testing of the test kits, he explained. He estimated it could take anywhere from a few weeks to a year to license such tests.
DeHaven said a Japanese team was in Washington, DC, today, meeting with federal agency officials to gather information about the BSE response. The team will go to Washington state to collect more information next week. A similar fact-finding team from Mexico will be in the nation's capital next week, DeHaven said. Japan and Mexico are among many US trading partners that have stopped importing US beef because of the BSE case.
In response to a question, DeHaven said milk from countries where BSE exists poses no risk to humans or animals. The international standard used by the World Organization for Animal Health (OIE) lists milk as one of the commodities that countries can export regardless of their BSE classification, he said. "There's no scientific basis for imposing a restriction on milk," he said.
Yesterday the USDA issued detailed rules to implement four of the new anti-BSE precautions announced Dec 30. The rules will take effect Jan 12, when they will be published in the Federal Register, the agency said. The rules:
- Specify that the USDA test carcasses for BSE and that inspectors not clear them for processing into food until they are found to be BSE-free.
- Ban the use of high-risk tissues, or "specified risk materials," from the human food supply; these include the skull, brain, trigeminal ganglia, eyes, vertebral column, spinal cord, and dorsal root ganglia of cattle 30 months or older, and the small intestine of all cattle.
- Exclude the dorsal root ganglia of all cattle and the skull and vertebral column of cattle older than 30 months from advanced meat recovery (AMR) systems, which separate muscle tissue from bone under high pressure.
- Ban air-injection stunning of cattle before slaughter, because of the risk that brain tissue can be driven into other tissues.
The USDA will accept comments for 90 days on the rules concerning specified risk materials, AMR systems, and air-injection stunning. (See the news release link below for the address and docket numbers for the rules.)
USDA Web site with link to recorded Webcast of Jan 9 news briefing
Food Safety and Inspection Service news release on rules implementing new BSE precautions