The source of bovine tuberculosis in a southern Alberta cow herd may be an enduring mystery.
The disease did not affect trade, but for those involved with the loss of 11,500 cattle, the impact was devastating, said a Canadian Food Inspection Agency official.
“How did it get here? All of us would like to know that answer,” Rick James-Davies said at the Alberta Beef Producers annual meeting, which was held in Calgary Dec. 4-6.
The CFIA ran a meticulous investigation, and there is no evidence of it spreading. It appeared to be in an isolated pocket.
Canada maintained its international status as TB free but will continue doing surveillance, mostly through slaughterhouses where the symptoms of the disease are visible in the carcasses of infected animals.
“It is important to remember it doesn’t mean there is zero TB in Canada,” James-Davies said.
“We have a program so we can claim our livestock is TB free, but because of the nature of TB, you can be a TB free country and from time to time have cases of TB.”
Testing of all commingled animals was conducted, but only six positives were ultimately found on one ranch in southeastern Alberta.
About 11,500 animals were ordered destroyed with more than $39 million in compensation paid to producers.
Many are restocking their operations, and the new animals must be tested to ensure they are disease free. They will be tested again next year to ensure no infection is left on the farm.
Another phase of the investigation involved tracing animals that left the infected operations over the last five years. This took investigators to 79 farms, and no positives were found.
Final tests should be done by Christmas.
More than 1,250 wild elk were tested during the 2016-17 hunting season, and no positive cases were found. However, Alberta Environment has a three year plan to actively survey wildlife. Samples from elk hunted in southeastern Alberta will be tested regardless of whether there are signs of disease at the time.
Traceability was a challenge during this investigation. Canadian Cattle Identification Agency ear tags were checked, as were farm tags, brands, brand inspection records, shipping manifests and auction market records.