OTTAWA — Mad cow disease seems to be losing its shock value, judging from the muted response to Canada's fifth confirmed case, but scientific concerns about the risk to public health continue to be debated.

Beef and livestock prices barely budged when the Canadian Food Inspection Agency confirmed this weekend that a B.C. dairy cow had tested positive for bovine spongiform encephalopathy, as mad cow disease is scientifically known.

The six-year-old dairy cow didn't make front pages, unlike her predecessors with the same condition in recent years when confirmed cases caused livestock markets to crash, raised swift trade barriers and caused widespread public comment, if not panic, far beyond agricultural circles.

The federal watchdog issued a simple news release insisting there was no public health concern arising from the B.C. case: "No part of this animal entered the human food or animal feed systems."

New cases are bound to be detected due to more testing, agency spokesman George Luterbach said Monday.

"There's a better understanding of BSE than there was in 2003," he said in an interview.

"The enhanced surveillance gives much stronger confidence that there is not a big problem out there."

Luterbach did not dispute claims that eating beef from an infected cow could cause a brain-wasting condition in humans, variant Creutzfeldt-Jakob Disease. He acknowledged there is some animal-human transmission, but at a very low rate.

Given that possibility, some critics say Canada and the United States are to blame for failing to tighten feed restrictions sufficiently.

"This shows that feed restrictions in place in Canada, and similar restrictions in the United States, are simply not adequate to control the spread of this disease," said Michael Hansen, a scientist with U.S. Consumers Union.

Canada's 1997 feed ban included what some critics saw as major loopholes. Cattle remains could still be fed to pigs and chickens, and pigs and chickens could still be fed to cows. Cattle blood could still be fed to calves.

"We have a situation in Canada and the United States where calves are still being legally fed cattle fat contaminated with cattle protein and cattle blood products," says John Stauber, the author of a book about mad cow disease, Mad Cow USA.

Many scientists have called for a complete ban on the use of slaughterhouse waste for feed of food animals and some jurisdictions have taken this advice, including the European Union, Japan and other Asian nations.

Japan tentatively reported its first case of mad cow disease Monday, but it was unclear where the infected animal came from.

Ron Glaser, director of communications at the Alberta-based Beef Information Centre, a beef industry lobby, says the public is over its fear of human mad cow disease.

"Over the last two to three years that our industry's been dealing with BSE in Canada I think consumers and media to a certain degree have come to understand that this is a fairly easy disease to manage and consequently this hasn't continued to get the media attention that it once did," said Glaser.

He seemed unconcerned about lost markets.

"We're able to trade beef into the Japanese market right now. A number of other markets are still closed, such as Korea and Taiwan. We're trying to regain those markets."

But a report from Tokyo says Canadian beef exports to Japan are only a fraction of what they used to be - about 20 tonnes a week compared with 500 tonnes before May 2003.