A new case of mad cow disease has been confirmed in a 13-year-old beef cow in Alberta -- the 11th such case since 2003, says the Canadian Food Inspection Agency.

"The animal's carcass is under CFIA control, and no part of it entered the human food or animal feed systems," it said Tuesday in a news release.

"The animal was born before the implementation of Canada's feed ban in 1997," it said.

"It's within the range of ages that we've seen before in Canada," CFIA spokesperson Marc Richard told CTV.ca about the latest discovery. "Definitely other cases have been in Alberta before ... so far, it totally fits the pattern of what we've seen in Canada."

The federal agency is attempting to identify the animal's herdmates and how it might have become infected, the CFIA said.

Richard said this latest case will not affect Canada's risk status with trading partners.

Mad cow disease is more formally known as bovine spongiform encephalopathy (BSE).

If beef from an infected animal is consumed by a human, that person is at risk of developing variant Creutzfeld-Jakob Disease. The fatal disease can linger in a person's body for years before they become symptomatic.

Richard said that people can only become infected if they eat part of the animal that's infected with the BSE prion. Those "specified risk materials" -- the brain and the spinal cord in older animals; part of the intestine in younger ones -- are removed from every cow at slaughter, he said.

Britain went through a mad cow crisis in the 1990s. In 1997, Canada imposed a ban on cattle feed made from rendered cattle or other ruminants. Such feed is suspected to be behind the British outbreak.

In May 2003, Canada's cattle industry was rocked when a cow from an Alberta ranch was confirmed to be infected with BSE.

Major trading partners like the United States, Mexico and Japan shut their borders to Canadian beef exports. The U.S. border would remain closed to live Canadian cattle sales for more than two years, costing Canadian producers billions of dollars in lost revenue. Starting in July 2005, the U.S. accepted cattle under the age of 30 months.

Richard said the best cuts of beef come from animals between 18 and 24 months old. Those animals are at relatively low risk of becoming infected with BSE.

The U.S. announced this fall it would move to allow older Canadian cattle to cross its borders.

In May 2007, the World Organization for Animal Health certified Canada as a "controlled risk" country, which is only slightly below "negligible" in terms of BSE risk.

The CFIA noted that an enhanced feed ban went into effect in July and should keep 99 per cent of potentially infective material out of the feed supply.

"The feed ban prohibits cattle-derived materials with potential to harbour BSE infectivity, such as the brain and spinal cord, from being used in all animal feeds, pet foods and fertilizers," it said.

"The CFIA expects to detect a small number of cases over the next 10 years as Canada progresses towards its goal of eliminating the disease from the national cattle herd," the agency said.