Mad cow disease or bovine spongiform encephalopathy (BSE) is the condition in which there is extensive wasting of the brain among the cattle. It is very fatal.
The Canadian Food Inspection Agency (CFIA) started its investigation when the fourth cow was tested positive for this disease.
The cow was home-grown and six-years old. The results of the investigation were that there were no additional cases of mad cow disease found in Alberta.
Gary little, acting senior staff veterinarian for the CFIA led the extensive investigation. The team studied about 156 cohorts, cattle from the birth farm born 12 months before or after the infected cow.
Out of this number only 38 were located alive on various Alberta farms. All of them tested negative for BSE.
CFIA reports that the remaining 118 animals had either died or had been slaughtered. The agency was not aware of the exact number of cows that would have been slaughtered for human consumption.
He also said that the large number of cows would have been slaughtered because when they are about 20 to 22 months of age, they do not display abnormalities related to mad cow disease.
Those animals that were tracked down was not sent to US but remained in the western province of Alberta. This also spurred a feed investigation at the farm, retail and mill levels.
This showed that the cow was born after 1997, when the Canadian government banned cattle from eating feed containing protein from cows and other ruminants such as goats and sheep, following Britain's mad cow outbreak.
This has resulted in closing down the markets for Canadian beef and cattle world over. But now that the investigation has said that no new additional cases were reported the trade has gradually resumed with strict regulations. There was loss of about $7 billion.