Dr. George Luterbach, a CFIA official, said "Worldwide, the most common route of the BSE agent is believed to be orally, or through the consumption of contaminated feed. Although the CFIA cannot determine where the cow has been born, and therefore can not speak about the feed, the most common assumption is that the animal in question was exposed to the BSE agent before the feed ban was introduced or during the implementation of the feed ban in Canada."

Luterbach said animals are the most susceptible to the BSE agent during their first year of life, and because the cow in question was approximately eight to 10 years of age, it was likely exposed to the BSE agent through feed before the ban.

Epidemiological investigation
Upon discovery of the BSE infected cow, the CFIA immediately initiated an epidemiological investigation based on the most recent World Organization for Animal Health (OIE) recommended BSE guidelines. No part of the carcass entered the human food sup ply or animal feed chain, a separate CFIA release said.