The first case was identified in late September 2016. The USDA informed the Canadian Food Inspection Agency (CFIA) that a Canadian cow had been diagnosed with bovine TB when it was slaughtered at a facility in Minnesota.
Only six cattle have tested positive for the disease through Jan. 11, according to a report from the CFIA, but officials on both sides of the border remain vigilant.
Although the outbreak in Canada provokes heightened awareness on the U.S. side of the border, measures have long been in place to prevent animals with TB from spreading disease.
TB is a contagious, chronic bacterial disease, which commonly involves the lungs and may spread to other organs, according to USDA’s Animal Plant Health Inspection Service.
Both Montana and North Dakota, which share the border with Alberta and Saskatchewan, already have standing requirements for TB testing on Canadian cattle entering the country. According to Susan Keller, North Dakota state veterinarian, every animal over 60 days old, with the exception of cow-calf pairs, in which only the dam is tested, must be tested for TB within 30 days prior to entry to the U.S.
“We feel that between Canada’s response and the fact that there are only six positives from the investigation, our standing requirements are sufficient to protect the state,” says Marty Zaluski, Montana state veterinarian.
Zaluski says that while producers may be nervous about contracting TB in their herds, there is not much they can do at this point past running a whole herd test. “We’re being vigilant; we’re focusing on safety and reviewing a bit about what TB is and how it is transmitted and how we test for it,” Zaluski says. “Overall, we want to make sure that we keep animals that are positive out of Montana, because to the best of our knowledge, there is no TB in the state at this point.”
Keller says that the USDA provides monthly updates on situations like the TB outbreak in Canada. The CFIA also provides information on their progress. “If it looks like they don’t have their arms around the situation at some point in time, then we may change,” Keller says. “USDA Veterinary Services is monitoring the situation, and if they feel like they need to ask for more testing, that would be conveyed to all the states.”
Canada’s method of dealing with outbreaks is more aggressive than the U.S. Zaluski says that Canada is quicker to depopulate, or slaughter, infected herds than U.S. procedure dictates.
According to Zaluski, the TB testing process can be a bit complicated. “It is initially a skin test, which can take a week to two weeks on those animals that respond,” he says. “If an animal continues to test positive on that test, it is taken to slaughter and a tissue sample is taken, and it’s another two weeks before those results come back to confirm the diagnosis.”
Keller says that producers in her state seem to be satisfied with the measures they already have in place. “I think they’ve been very comfortable with the fact that the Board of Animal Health here has always had a TB test requirement from Canada,” she says. “I think that sometimes there are many people, especially in Canada, that live on our border that think it’s too much testing. At a time like this, it gives us some measure of comfort to know that we have always had this TB test requirement in place.”
According to Zaluski, TB is readily transmitted from animal to animal in a close-proximity setting. TB is a respiratory disease that can spread fairly easily through a herd. “On a herd basis, you can get a reasonably decent spread either from direct nose-to-nose contact or contamination of feed by one positive animal that is followed by another animal coming right next to it or right after it and consuming some of that same feed,” he says.
He also says that, while outbreaks that initiate quarantining thousands of cattle are out of the ordinary, finding an animal with TB isn’t a terribly rare experience. Zaluski says the first animal found in September at the slaughter facility was one of perhaps 10 cases identified in the last fiscal year.
Keller says she is grateful that Canada’s officials are throwing a big net and testing so many animals. “I know that they have many places, and I think it seems alarming on one hand that they have all of these herds that were quarantined and tested, but on the flip side, they’re doing that out of caution, just as we would want them to,” she says. “We want them to maybe test more herds than are needed because that way they are not letting something slip through the cracks, so trace ins, trace outs, neighbors, they are making every effort to test everything that might be at risk. We respect and we commend that, and if they find more cases and they need to broaden anything and we feel we need to do more, we will.”
Investigations of this scale can take several months, so while officials and producers on both sides of the border should stay vigilant, there seems to be no immediate danger to U.S. herds. 
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Carrie Veselka
- Staff Writer
- Progressive Cattleman
- Email Carrie Veselka
PHOTO: Tuberculosis can easily be spread through close proximity like nose-to-nose contact or sharing the same feed space at a feedbunk. Staff photo.
