Most herds or flocks of animals are NOT infected with M. paratuberculosis. Learn how to keep your animals free of this infection.		"An ounce of prevention is worth a pound of cure". Disease prevention is always more cost-effective than control and treatment. This is even more true for Johne's disease since it is not treatable. Specific details of infection prevention practices are found under each specific animal species topic.

Prevention is the most cost-effective way to manage Johne's disease. It is far less expensive to block introducing Johne's disease into a herd/flock than it is to control or eradicate the infection once it creeps in and invisibly starts to spread. Risk management is the foundation of any good animal care program and the risk of becoming infected by bringing in infected animals is manageable. Smart buyers of animals will apply the concepts of risk management and require diagnostic test results for the source herds or flocks to limit their risk as much as possible. If sellers refuse to allow their herds or flocks to be tested before you purchase their animals, there is a good likelihood their herd or flock may be infected. Find another source of animals from whom to buy if possible or at least test the individual animals you are contemplating for purchase.

For dairy enterprises (in the US, the domestic agriculture industry believed to have the greatest prevalence of the infection), owners must assume that they are buying M. paratuberculosis-infected animals on a regular basis if they do not purchase from test-negative herds. The buyers must then be sure to have animal husbandry systems in place to try to control the further transmission of the infection.

Other routes by which Johne's disease may be introduced to herds/flocks exist, but they are of much lower risk (although data is limited quantifying these risks). These other routes include use of semen or embryos from animals of unknown Johne's status, spreading manure from potentially infected farms on land the herd owner uses for grazing or forage production, use of colostrum or milk from dairy herds of unknown status for hand-rearing orphaned neonates, or animal access to run-off water from adjacent farms. These routes are theoretically important, but the risk of acquiring the infection from them is likely much lower than through the purchase of animals.

The key to success is to know the infection status of source herds for animals you want to buy. You are better off buying a test-negative animal from a dairy herd with a low test prevalence than buying an animal from a herd that cannot provide any information about their Johne's disease history. For animal industries, self-regulation to encourage marketing of animals from test-negative herds or flocks is the best way to manage this emerging disease problem.