BISON: CONTROL - JOHNE'S INFORMATION CENTER

Caveat: most information on M. paratuberculosis infection and Johne’s disease has been obtained through studies on domestic species (for example cattle, sheep, goats). While it is believed that this information likely is applicable to bison as well, there may be some facets that differ for which we do not yet have a good understanding. Please bear this in mind as you use this web-site.

	It takes patience and consistent management to control Johne's disease once it is established in a bison herd. The good news is that it can be done and management changes recommended for John'e disease control will also help control many other infectious diseases

There are many factors affecting the design of a
Johne’s disease surveillance and control program:

the reason the bison are being raised,
the husbandry patterns and breeding plans,
the estimated prevalence of Johne's disease,
the importance of Johne's disease control relative to other husbandry/health issues
the number/frequency of new introductions from other herds
the resources (labor, budget, etc.) available
the rate at which M. paratuberculosis infection control is needed, and
whether the goal is to control vs. eradicate the infection.

Photo of bison herd Since an effective program must closely reflect the resources and requirements of each individual facility, the following is meant to provide a general framework only. An element in common for any surveillance effort however is to look beyond individual animals to groups of animals sharing exposure and control factors, such as different range areas or enclosures. Johne’s disease should be considered a herd, not an individual animal, health problem.

If M. paratuberculosis infection has been confirmed previously, it is likely that other bison are infected as well but may be asymptomatic. The next step should be to decide how aggressive the manager needs/wants to be to address these other potential cases and prevent the spread of the infection. To do so, s/he needs to assess whether and when (at what age) other bison were exposed to the infected animal(s) and if there were other cases in the recent past that in retrospect fit a M. paratuberculosis infection disease profile but may not have been assessed for the infection. If the goal is to control or eradicate the infection, it will be necessary to identify and test these animals. Test-positive animals need to be culled or segregated from other animals.

Since a single round of testing may not identify all infected animals due to infrequent shedding of the organism, the manager should begin longer term surveillance to include, if feasible:

1.		Assessment and recording of body condition to include palpation of ribs/spine whenever handled.
2.		Annual testing of bison exposed to manure from the confirmed case.
3.		More frequent testing for offspring of the confirmed case(s) and animals exhibiting weight loss or diarrhea. These animals should be segregated until a diagnosis explaining these clinical signs is reached.

It is important to block the spread of the infection by preventing calves from being exposed to potentially contaminated manure. Ways to help accomplish this include:

1.		Prevent manure from contaminating feeders and waterers; minimize areas of standing water.
2.		Clean with a phenolic based disinfectant since M. paratuberculosis is believed to be resistant to many disinfectants such as chlorine bleach, etc.
3.		Perform complete necropsies, including culture and microscopic examination of the ileum and mesenteric lymph nodes, on all bison dying on site, no matter what the immediate cause of death.

While not directly pertinent to bison in some aspects, see the web pages under Dairy-Control for a broader description of this topic.