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Animal Health

Test finds Idaho cow positive for brucellosis

Written by Christy Hemken
    “It’s too early to say if there will be an impact on Wyoming,” says Wyoming State Veterinarian Jim Logan in response to news that a beef cow in Idaho has tested positive for brucellosis.
    He notes that there could be, should the animal be linked to a Wyoming herd. “But I don’t expect that to happen because of Wyoming’s surveillance and testing requirements,” he explains. “When cattle leave our surveillance area they have to be tested, no matter where they’re going.”
    The brucellosis-positive cow was found as one of a 600-cow herd recently assembled in the Rigby, Idaho area near the state’s eastern border. Idaho State Veterinarian Bill Barton says the cattle came from a variety of sources, including private sales and livestock markets.
    Logan says, theoretically, if an animal had come from Wyoming’s area and been purchased into the herd, it would have been tested, with negative results, otherwise he would have known about it.
    The Idaho herd has been quarantined and is being tested while epidemiologists determine the source of the infection. Barton expects testing to wrap up in the first week of December.
    According to Barton, no calves or bred cows have been sold from the herd, and no cattle have been sold other than to slaughter.
    The positive brucellosis test came during the last week of the open comment period for the proposed “Concept Paper” regarding a new direction for how APHIS handles brucellosis in the U.S. The comment period closed Dec. 5.
    “It’s coincidental they found the case just before the deadline for comments,” says Logan. “But this is an opportunity to test the concept of how APHIS will handle cases found in the Greater Yellowstone Area.”
    “I would hope that Idaho won’t lose their free status and this will be something confined to one herd and just a single animal,” notes Logan.
    Idaho was granted brucellosis-free status in 2007 after losing the status in 2006, when the disease was found in a cattle herd in Swan Valley near the Wyoming border.
    Logan says the key point in this newest positive case is that it’s not an unexpected event. “To find brucellosis in cattle in Idaho, Wyoming or Montana occasionally is pretty much to be expected,” he says. “Regardless of how good producers do with mitigation and prevention efforts, the risk is still there and occasionally there will be cases that show up.”
    Logan says all three states have a surveillance system and brucellosis rules in place, and when transmission occurs it’s a good demonstration of their success when the system picks up the cases in a timely fashion before they have the opportunity to spread to other herds.
    “It’s to the credit of all three states that we’re finding these cases quickly,” he says.
    Christy Hemken is managing editor of the Wyoming Livestock Roundup and can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..