Cattle Johne's Disease and Herd Welfare Management

Johne's disease, caused by Mycobacterium avium subsp. paratuberculosis, is a chronic, progressive wasting disease of ruminants for which there is no treatment. Herd health programmes focus on limiting transmission to calves and culling affected animals before clinical signs develop.

Key Facts

Johne's disease is endemic in dairy herds globally, with herd prevalence exceeding 50 per cent in some regions
Infected cattle shed MAP in faeces for years before showing clinical signs, maintaining a hidden reservoir within the herd
Clinical signs — profuse watery diarrhoea and progressive weight loss despite normal appetite — typically appear in cattle three to five years of age
No treatment is available; affected animals deteriorate progressively until death or welfare euthanasia becomes necessary
Calves are most susceptible in the first 30 days of life — preventing calf exposure to adult faeces is the cornerstone of control

Welfare Considerations

Cattle in the clinical stage of Johne's disease experience severe protein-losing enteropathy causing progressive weakness, dependent oedema, and profound weight loss while remaining alert and continuing to eat — a distressing dissociation between appetite and the body's inability to absorb nutrients. End-stage animals are unable to rise and require prompt euthanasia to prevent prolonged suffering. Welfare-centred herd programmes identify infected individuals through annual ELISA testing and cull positive animals before clinical disease develops, eliminating the most severe suffering while reducing herd-level transmission. Strict calf hygiene protocols protect the next generation.

What You Can Do

Implement annual ELISA testing of all adult cattle to identify subclinical MAP shedders before clinical disease develops
Apply strict colostrum hygiene protocols — use colostrum only from ELISA-negative dams and feed promptly from individual cows
Separate calving pens from adult cow areas and clean and disinfect between uses to minimise environmental MAP contamination
Cull ELISA-positive animals promptly rather than carrying them to clinical disease to prevent welfare harm and transmission
Work with your vet and animal health adviser to develop a written Johne's disease control plan appropriate to your herd prevalence level