The Canadian Food Inspection Agency has confirmed a case of mad cow disease in an older dairy animal in Alberta, the 16th case detected since 2003.

The agency says the cow with bovine spongiform encephalopathy, or BSE, was 6½ years old. It says no part of the animal's carcass entered the human food or animal feed chains.

The animal's birth farm has been identified and an investigation is underway.

"The age and location of the infected animal are consistent with previous cases detected in Canada," said the CFIA, which has blamed infected feed for most of the earlier cases of the disease.

The case is not expected to affect exports of Canadian cattle or beef.

Mad cow disease is believed to be spread when cattle eat protein rendered from the brains and spines of infected cattle or sheep. Canada banned that practice in 1997.

The CFIA tightened feed rules further in 2007, and said this should help eliminate the disease nationally within a decade, although it cautioned it still expected to discover the occasional new case.