Brucellosis and Montana Cattle Ranchers

While brucellosis in cattle herds seemed eradicated in 2001, the disease is back in herds of elk and putting Montana cattle ranchers on high alert. A study conducted by the Montana Fish, Wildlife, and Parks Department from January 30 – February 3, 2015 found high numbers of elk with the disease. Researchers discovered one herd where 50% of the elk were infected with the disease. Brucellosis causes pregnant wildlife and cattle to abort their young – a major concern for cattle ranchers. It is common for the cattle and elk to interact and transmission can occur through ingestion or through any mucous membranes, wounds, etc.

Solutions to this problem are not easy. One simple solution is to move the cattle herds to lower elevations where the elk would not roam. However, most ranchers cannot move their cattle far enough away due to the frequent co-mingling among species. Another option, one already used in 2014 by the Montana Fish and Wildlife Commission, is exterminating diseased elk, sometimes whole herds. There are obvious objections to this plan, but it does prevent the spread of the disease. One of the more viable options is vaccinating cow calves. Vaccination of cattle has occurred since 1941 when the Strain 19 vaccine was used, but today a more effective RB51 vaccine is given to young cattle. So far, vaccinating calves is a proven means of brucellosis disease control and even though vaccination can be costly, it is ultimately cheaper than the loss ranchers would suffer having to slaughter affected cows.

The next step for Montana ranchers is finding a way to keep the elk from their cattle, which is easier said than done. A controversial plan to fence out, haze or kill infected elk to prevent disease transmission was approved in 2014 by the Montana Fish and Wildlife Commission for Paradise Valley and will be reviewed in 2016. The plan appears to be working with reports of no positive tests in elk over the past year and little loss to elk herds.

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