Ranchers in the three states have been harmed by instances of brucellosis in cattle in recent years. The disease is carried by elk and bison in the Greater Yellowstone Area and can cause cows to miscarry. The federal government is now crafting a new brucellosis management policy. Ranchers have balked at vaccinating all heifers between the ages of 4 months to a year, arguing the $5 shot isn’t needed for young females raised for food.

Members of two of Montana’s largest livestock groups, the Montana Stockgrowers Association and Montana Farm Bureau Federation, have formalized policies officially opposing the vaccination of all sexually intact female calves because they think it’s unnecessary. The Farm Bureau supports vaccinating only breeding heifers and heifers imported to Montana for that reason.

Ranchers have also suggested waiting until the heifers are older and then vaccinating only those selected for breeding who could pass the disease onto their young. "This gives us more flexibility be extending the age, but you have longer periods without vaccination, too.”

If mandatory vaccinations took effect, there would have to be penalties for not complying, Zaluski said. Given the size of the state’s cattle herd, it would be impossible to move forward with the vaccinations without the support of cattle ranchers and those raising bison, which would also be subject to the law.