The best way to avoid introducing this disease into your herd is to be certain that ruminants brought onto your property are not infected with the causative bacteria. Many states have Johne's control/prevention programs; participation in these programs is voluntary. These programs help identify the disease status of individual animals and help owners work toward a disease-free herd status. Ask your prospective seller if he/she participates in such a control program; do not hesitate to ask for proof.
Pre-purchase screening of animals may be of some benefit. However, it is important to understand the limitation of the tests for Johne's. Involve your veterinarian in any discussion of laboratory testing and test results.
