Brucellosis may only affect a small area of the country, but it can have a big impact. Similarly, changes to the rules surrounding it can have a big impact.
On Oct. 11, the Montana Department of Livestock (MDOL) announced changes to the brucellosis vaccination rules, as well as an expansion of the Designated Surveillance Area (DSA) for the disease.
Prior to the announcement, the DSA covered Gallatin, Madison, Park, and Beaverhead counties. All sexually-intact female cattle or bison over the age of 12 months residing in or entering the counties for seasonal grazing were to be vaccinated for brucellosis as calves.
The new rule, ARM 32.3.433, has expanded the DSA to six additional counties; Big Horn, Broadwater, Carbon, Jefferson, Stillwater, and Sweet Grass. The MDOL noted that the DSA has expanded three times since 2009.
“Each expansion was made in response to findings of brucellosis in elk, which required the inclusion of additional cattle and domestic bison in the surveillance program,” the MDOL wrote in its official announcement of the rule.
“Undetected disease spread outside of Montana’s DSA could jeopardize Montana’s federal brucellosis Class Free status, and in 2008, a loss of brucellosis Class Free status was estimated to have cost Montana’s producers up to $11.5 million annually.”
The new rule additionally removes both the focus on calfhood vaccination and the Dec. 1 cutoff date for completing vaccinations.
“This gives producers more options for the management of replacement heifers and allows animals to be vaccinated as adults,” wrote MDOL.
Impacts to producers
Jay Bodner, executive vice president of the Montana Stockgrowers Association (MSGA), told WLJ there will be some noticeable impacts to area ranchers.
“This expansion will include an additional 10,000 head of cattle that will be required to do additional testing. There will be an additional cost to the state that is approximated at $150,000. Livestock producers in this new expansion area will have to factor in these new testing requirements as far as timing and veterinarian availability as their animals move in or out of this area.”
MSGA Manager of Communication, Kori Anderson, told WLJ that many Montana producers already vaccinate as a precautionary measure, particularly since the DSA has expanded over the years.
“Certainly, our concern is, ‘Will the DSA keep expanding?’” said Anderson. “Will we keep seeing this pushed out further and further?”
Bodner echoed this concern, but voiced appreciation for the efforts of the MCOL.
“In our view, this measured approach to a DSA expansion, based on the scientific criteria, will protect our brucellosis Class Free status. This approach shows how the state of Montana is making science-based decisions.”
He added that, “The DSA will only expand based on potential risk of infection by brucellosis-positive elk populations. As the elk population continues to expand, there is potential for this DSA boundary to expand.”
There have been ongoing efforts and conflicts over the management of brucellosis in wildlife populations. Until relatively recently, brucellosis infections in domestic cattle and bison in the Greater Yellowstone Area were largely blamed on contact with infected wild bison.
A 2017 report from the National Academies of Sciences found that infected wild elk were the primary culprits for cattle infections in the area. The report made several recommendations regarding managing the disease in elk, including reducing the population and phasing out or closing elk feed grounds.
Past efforts focused on bison have included removal of animals that stray into certain areas and keeping a cap on the population. These past efforts and the suggestion of similar efforts with the elk have been criticized by environmental groups and anti-grazing wildlife groups, which generally argue the onus should be on livestock to control the disease.
Research restrictions
In speaking with WLJ, Anderson voiced a hope for increased research into tackling brucellosis. However, the infectious agent that causes brucellosis, Brucella abortus, is on the federal Select Agent Program list. This list is made up of various viral and bacterial agents that pose extreme danger to human and/or animal life and could be used as bioterrorism agents. Foot-and-mouth disease, Ebola, anthrax, and African swine fever are all examples of listed agents.
“That greatly restricts who can have access to it,” Anderson pointed out of Brucella abortus. She added that land-grant universities were the most likely entities to conduct more research on eradicating brucellosis, given its relatively small area affected by it.
“Those land-grant universities can’t get their hands on it,” she continued. “We are really pushing to get it delisted.”
“Through our work, there has been a general recognition that brucellosis research doesn’t raise to the level of a bioterrorism agent,” Bodner said of the listing issue, but added, “It is an extremely slow process to get this removed.” — Kerry Halladay, WLJ editor
