The United States Department for Agriculture (USDA) said that this DNA evidence was based on a comparison of DNA from the brain of the positive cow with the DNA from semen of her sire and was confirmed by both US and Canadian animal health laboratories.
Additional DNA testing continues, involving the heifer calf on the index farm which was born from this positive cow. Breeding records on that calf confirm that the animal was born from the cow bearing the tag number found at slaughter and found in the records on the farm in Alberta.
This new DNA information, coupled with the documentation that the USDA has obtained from its colleagues in Canada, the owner of the dairy farm in Mabton, Washington, and from import records, further increases the USDA's confidence in the accuracy of this traceback.
Other elements of the investigation continue on both sides of the border and may provide additional information. This includes the cattle feed investigation in Canada as well as the additional DNA testing.
Canada's Chief Veterinary Officer, Dr Brian Evans, said that 17 young stock from the BSE-infected animal's birth herd also arrived in the United States as part of a later shipment. USDA and Canadian officials are currently working to confirm if any or all of these 17 animals-all heifers-did in fact enter the United States.
The USDA has also stated that the safeguards now put in place are enough to ensure the safety of America's meat supply. The Institute of Food Technologists, a non-profit scientific society specialising in food science, has also gone on record as saying that it is confident that surveillance systems within the US food supply chain are sufficiently rigorous.
IFT president Ann Hollingsworth has pulled out all the stops in her attempts to convince the world of this fact. "Finding a case of BSE in the United States does not mean the system is broken," she claimed. "It means our system for detection and response works."
IFT says that it supports the policies USDA has designed to further protect against BSE including banning of all downer cattle from the human food chain, prohibiting air-injection stunning during slaughter, and strengthening the regulation of specified risk materials.
"The USDA's immediate ban from the human food chain animals that cannot walk should help restore confidence that America's beef is safe," said Hollingsworth. "The same can be expected of the confinement and testing of cattle at risk of having nervous-system disease.
"There is no scientific basis for testing vast amounts of slaughtered cattle, nor are there laboratory resources for such a system, nor the means to store safely for extended periods all the beef that ultimately is safe."
The IFT also applauded the effectiveness of the US Food and Drug Administration's BSE-prevention measures, including its investigation of all organisations involved in processing the animal and its coordinated effort with state and other officials to halt the distribution of all meat and bone meal from the infected cow.
The United States is the 24th country to diagnose a case of bovine spongiform encephalopathy within its borders.