Toronto Canada on Thursday confirmed its second case of mad cow disease in as many weeks - and seventh since 2003.
Shipments of cattle to the United States were halted in 2003 after the first reported cases of mad cow in Canada. Trade in cows younger than 30 months resumed last July.
The latest case was of a 50-month-old dairy cow from a farm in western Alberta, and the U.S. Department of Agriculture said it would send an inspector to aid in the investigation into the death.
Last week, Canadian officials said another Albertan cow died of bovine spongiform encephalopathy, an extremely rare disease that can be fatal in humans.
The carcass of the animal was incinerated and did not enter the human or animal feed system, Canadian Food Inspection Agency officials said in Ottawa.
The cow, part of a herd of 300 head of cattle on an Edmonton-area farm, was among 170 other cows that will now be tested for the disease. Those animals were born within a year of the diseased cow and are either on the same farm or have been sold to other farms.