Brucellosis Zone Could Expand Beyond Yellowstone

Bison calf being processed at the Stephens Creek Facility YNP
Bison calf being processed at the Stephens Creek Facility YNP

The state of Montana is considering expanding the area around Yellowstone where livestock must be vaccinated and tested for the livestock disease brucellosis after several elk tested positive for the disease in the Ruby Mountains.

Montana animal disease zone could expandAP

What this may mean for wildlife in the area is still uncertain.  Threat of Brucellosis infection has been used by Livestock interests in the state of Montana to justify a brutal campaign to keep Yellowstone bison inside Yellowstone National Park and off of other public land habitat where bison would otherwise compete with public land livestock for forage.  No documented transmission of Brucellosis from bison to cattle has ever taken place in the wild.

Recent occurrences of the disease in livestock in southwest Montana have been verified with evidence suggesting the most likely source being elk.




  1. Ralph Maughan Avatar

    It’s always elk when it comes to cattle acquiring brucellosis, except for those cases when it is other cattle.

    It has never been bison. Not even once.

  2. Ann Avatar

    Ignoring the facts don’t make them go away. NEVER have Bison transmitted BACK to cattle. unless humans stuffed the disease in every orifice. And humans are supposed to be the smarter species?

  3. ProWolf in WY Avatar
    ProWolf in WY

    People seem to be in denial it is always elk that are carrying brucellosis.

  4. Immer Treue Avatar
    Immer Treue

    Just a question out of pure curiosity, but have elk in N Yellowstone herd or Lolo elk been checked for brucellosis?

    1. Ralph Maughan Avatar
      Ralph Maughan

      The Northern Yellowstone herd is infected with brucellosis. It is the likely source of almost all cattle brucellosis infections in Montana. The Jackson Hole elk herd and herds to its immediate south are very highly infected and the reason why both Wyoming and Idaho have lost their official brucellosis free status several times in the last decade. I have never herd of the Lolo elk having brucellosis or any cattle cases in the area.

    2. Mark Gamblin (IDFG) Avatar
      Mark Gamblin (IDFG)

      Immer –
      Can’t say with certainty, but there is no reason to check for brucellosis in the Lolo elk herd. No or very little cattle production in the Lolo Zone.

  5. Immer Treue Avatar
    Immer Treue

    Ralph and Mark,

    Thank you for the reply. Needless to say, one answered question always leads to another question. I am very aware of the N Yellowstone elk population fluctuations over the decades, and also am aware of the Lolo elk population slide over the past couple decades with the very low calf to cow ratio in Lolo. Wolves and bears do have an impact on calf survival.

    So this leads to the next question. Does brucellosis have any impact on the elk population, or is it just that they carry the antibodies for it, and are largely unaffected by the effects of brucellosis?

  6. Nota Avatar

    Rammell making threats in Idaho Falls.

  7. Ann Avatar

    A rather interesting fact. With Texas next to Mexico, and the brucellosis problems down there. Why in the WORLD would Texas drop Mandatory Brucellosis testing? hmmmmmmm is it because the facade is showing? the fact that it really is NOT about disease.


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Brian Ertz