The tests results are in and the news is not good for Alberta beef farmers–the U.S. mad cow was in fact a Canadian.

DNA tests prove that the Holstein dairy cow from a Washington state farm that tested positive for bovine spongiform encephalopathy (BSE), or mad-cow disease, was part of a herd brought into the U.S. from an Alberta farm.

The tests were performed on the infected cow, one of its offspring and semen samples from the bull that sired it.

U.S. Agriculture Department chief veterinarian Ron DeHaven told a media briefing that there was "a high degree of certainty" that the infected cow came from Alberta.

The news comes as a fresh blow for a Canadian beef industry still trying to shrug off the stigma of the mad cow case discovered in Alberta in May. Bans remain in affect in a number of countries, including the two largest foreign markets for Canadian beef-–the U.S. and Mexico.

So far the bans have cost the Canadian beef industry an estimated $1.9 billion in lost revenue.

However, Dr. Brian Evans of the Canadian Food Inspection Agency emphasized that, after May's discovery, there was always the possibility that additional cases of mad cow among Canada's herds would be found. He said the latest findings do not change the situation in any significant way.

"We have always accepted the reality that a small number of additional cases could not be ruled out over the next 18-moth period," he was quoted by the Globe and Mail. "From that standpoint this is not a shocking discovery. It certainly does provide some disappointment to the industry who will psychologically bare that aspect."

Both officials said mad cow remains a North American problem, not just Canada's. A joint effort will continue to locate other animals from the same herd as the infected Holstein and track the sources of feed that may have led to the infections.

Meanwhile, Canadian Agriculture Minister Bob Speller emphasized that Canadian, and North American, beef remains among the safest in the world.