A CBC report last week said that documents obtained through Access to Information show that the Canadian Food Inspection Agency had discovered cattle at a number of farms were eating feed intended only for pigs and chickens.
That feed may have contained the rendered remains of the diseased cow.
Oganisations such as the Ranchers-Cattlemen Action Legal Fund (R-CALF USA), which represent the interests of the US beef industry, have urged the USDA to take decisive action.
"These recent reports of BSE problems within Canada's BSE-firewalls would be harmful to the US cattle industry if USDA does not adequately maintain our import standards," said R-CALF USA president Leo McDonnell.
"This issue within Canada will make it very difficult for USDA to provide scientific support for the further liberalisation of US import standards."
BSE is understandably a sensitive issue. Following the discovery of the BSE-infected cow - a disease that has been linked with the fatal human neurological condition variant Creutzfeld-Jacob Disease (vCJD) - Canadian beef was immediately barred access to all of its major export markets.
Earlier this year, a Wall Street Journal Online/Harris Interactive Health-Care Poll in the US showed that one in every five American adults - 21 per cent - said that fear of mad cow disease would change their eating habits, while 78 per cent of these people said that they would eat less beef.
Some 16 per cent indicated that they would stop eating beef altogether.
And in the UK, domestic sales of beef products declined immediately by 40 per cent following reports of a possible link between BSE and new variant CJD in 1996, with export markets completely lost. This is why R-CALF is so anxious to distance its industry from any possible BSE taint.
R-CALF is also angry because it believes that the USDA's Animal and Plant Health Inspection Service (APHIS) has known of this problem for more than a year. R-CALF USA cited an APHIS report dated 3 October 2003 as the source of this information.
"It has not adequately addressed this problem, especially in light of its own efforts to liberalise US import standards when dealing with countries like Canada where BSE has been found," said McDonnell.
R-CALF claims that the risk associated with importing Canadian beef was recognised by US district judge Richard Cebull, who granted the organisation a preliminary injunction against USDA in May.
This blocked APHIS from allowing additional Canadian beef products (other than boneless beef) from being imported into the United States.
"Since there are no requirements that imports of Canadian beef products be labelled to indicate the country of origin, once those products cross the border they become virtually impossible to recover or segregate if additional cases of BSE are discovered in the Canadian herd," Cebull wrote in his ruling.
R-CALF promises to fight to ensure that the US beef industry can guarantee that its products are free of any possible BSE contamination. But some experts argue that the accepted theory of a prion as an infectious agent that leads to BSE is erroneous, and argue that the cause of BSE may be something else, such as the use of neurological toxins found in some insecticides.
They believe that the accepted version of events is based on a theory that is far from proven and should be widely disputed.
"I agree with the decision to stop feeding animal by-products to ruminants," Canadian farmer Ken Conrad told FoodProductionDaily.com earlier this year.
"However I do not believe that Mad Cow Disease, BSE or vCJD result due to the consumption of a mutated prion protein, or that it is transmitted from animal to animal."
Conrad contends that there is mounting evidence to suggest that the mutated prion is more than likely a pathologic product. In other words, it has resulted due to some form of outside environmental and/or biomedical interference.