Canada Can't Locate Birth Farm of 6th Mad Cow Case

WINNIPEG, Manitoba — The Canadian Food Inspection Agency said Tuesday it could not confirm the birth farm of Canada 's sixth mad cow case since 2003 due to a lack of information on the animal's history.

The mature cross-bred beef cow was "at least 16 years old" when it died on a Manitoba farm earlier this summer, the federal food safety agency said in a release as it wrapped up its investigation.

The brain wasting disease, also known as bovine spongiform encephalopathy or BSE, is believed to be transmitted through contaminated feed. The affected animal was born well before the 1997 feed ban on cattle feed containing protein from rendered cattle and other ruminants.

Since cattle are most likely to contract the disease in their first year of life, the CFIA said the cow was most likely exposed to the BSE agent in 1989 or 1990 when the inclusion of meat and bone meal in cattle feed was both accepted and legal.

The cow, which was confirmed to have BSE on July 4, was purchased by its owner in 1992. No part of the animal's carcass entered the human food or animal feed supply, the agency said.

Investigators traced the location of the 21 herdmates that had been purchased with the affected animal. Only one was still alive and tested negative for BSE, the agency said.

The CFIA confirmed a 50-month-old dairy cow from the Prairie province of Alberta tested positive for mad cow disease later in July, making it the country's seventh case since 2003. This prompted the United States government to halt its proposal to allow imports of older Canadian cattle until the investigation was complete.

That animal was born after the 1997 feed ban and died on the farm on which it was born.

The U.S. Department of Agriculture has been observing the Canadian investigation, which is nearly complete. A report on the findings is expected to be finalized within days, the CFIA said.

Canada announced in June that it aims to eliminate mad cow disease within the next 10 years by banning high-risk tissue from all livestock feed, pet food and fertilizers.