Johne’s Disease: How to Prevent Introduction into Your Herd

One of the major challenges in managing JD is its slow and silent progression. Infected animals often show no signs until they have had three or more calves, by which time the infection may already be well established in the herd.

1. Purchasing Infected Animals
   JD-positive animals may appear healthy and can even test negative, but they may still shed large quantities of MAP bacteria in their faeces, contaminating the environment and posing a major risk, especially to younger animals.
2. Importing Contaminated Colostrum
   Colostrum can carry MAP if harvested in unsanitary conditions or sourced from infected cows.
3. Bringing in Slurry or Manure
   Importing manure (excluding pig or poultry manure) from a MAP-positive farm risks contaminating your pasture, especially endangering young stock.
4. Off-Farm Animal Movements
   Animals that leave your farm, such as to shows, marts, or contract rearing units, can pick up JD by grazing on contaminated land or coming into contact with infected faeces.
5. Visitors and Workers
   People can unknowingly carry MAP-contaminated material on boots, clothes, or equipment between farms, particularly endangering calves and young stock.
6. Contaminated Vehicles and Equipment
   Machinery, trailers, and other farm vehicles can spread infected faeces if not properly cleaned before entering your farm.

1. Limit Animal Purchases and Source from Low-Risk Herds
   Buy from closed herds or those with a history of negative Whole Herd Tests (WHT). Participants in the Irish Johne’s Control Programme (IJCP) can provide a Herd Summary Report showing compliance and testing history.
2. Avoid External Colostrum
   Never bring in colostrum from outside your herd unless it comes from a trusted, high-assurance source.
3. Avoid Importing Slurry or Manure
   If necessary, ensure it is not applied to land grazed by young stock. Contractors should clean vehicles and machinery before accessing your farm.
4. Manage Off-Farm Grazing Carefully
   Avoid land recently spread with slurry and assess biosecurity at rearing units before sending calves or heifers.
5. Control Farm Access for Workers and Visitors
   Restrict access to high-risk areas, especially those housing young stock. Provide clean overalls and boots and install cleaning and disinfection stations. Use signs to highlight biosecurity rules.
6. Sanitise Vehicles and Machinery Before Entry
   Ensure external and internal surfaces are clean, particularly high-risk equipment like livestock trailers and slurry spreaders.

Restrict Visitor Access and Establish Entry Controls
Limit entry points and use gates, signage, disinfection points, and footbaths to manage movement and protect vulnerable stock.