Paratuberculosis, commonly known as Johnes disease, is a chronic progressive bacterial enteritis of cattle causing severe wasting, diarrhoea, and premature death, representing a significant welfare and economic burden.
Key Facts
Johnes disease is caused by Mycobacterium avium subspecies paratuberculosis (MAP)
Most cattle are infected as calves through faecal contamination of milk or colostrum
Clinical signs typically emerge at 4-6 years of age after a long subclinical phase
Profuse watery diarrhoea and progressive weight loss are the hallmarks of clinical disease
There is no effective treatment; control depends on testing, culling, and hygiene measures
Welfare Considerations
Clinically affected cattle with Johnes disease suffer prolonged and severe welfare impacts: the chronic protein-losing enteropathy causes weakness, weight loss to skeletal appearance, and profuse diarrhoea. Animals in advanced disease stages are in poor body condition and likely experience significant discomfort. The long subclinical incubation period means welfare harm is difficult to detect early. Herd health plans focusing on reducing calf exposure and early culling of test-positive animals can reduce the burden of suffering.
What You Can Do
Enrol in national Johnes disease accreditation or risk reduction programmes
Implement clean colostrum management to reduce calf exposure to MAP
Test regularly and promptly act on positive results to prevent disease progression
Support research into diagnostic tools and vaccines for Johnes disease control