Continued analysis of the AHDB heifer cohort to evaluate the importance of early life management on the risk of Johne’s disease and support farm-level decisions

Key outcomes

To identify the most important early life risk factors for Johne’s disease and the costs and benefits of culling cows that test positive to enable informed decision making by dairy farmers on disease prevention and control.

1. To estimate the reduction in risk of infection that can be expected by implementing specific Johne’s disease control measures around the time of calving
2. To estimate the financial gains associated with implementing specific Johne’s disease control measures
3. Better understand potential interference between bTB and Johne’s disease test results
4. To inform and make recommendations to the industry via the Johne’s Action Group

Benefits

• Provide a more targeted approach to controlling the disease and could save a herd of 200 milking cows between £7,000 to £11,000 per year by reducing losses.
• Environmental benefits include reduced greenhouse gas emissions associated with more efficient production as well as the enhanced industry image via improved animal welfare.

Johne’s disease causes major financial losses to the British dairy industry through reduced health status and poor productivity. This often leads to premature culling of affected cattle. Johne’s disease cannot be treated, so its prevention is vital. A serious problem when studying Johne’s disease is that symptoms take a long time to develop. A further problem is that disease transmission is poorly understood. A previous study in the AHDB Research Partnership 1 looked at a group of 500 dairy calves for the first two years of their lives. These heifers were monitored for signs of Johne’s disease and the data was used to identify potential risk factors for disease transmission. The same group of heifers are now being monitored to evaluate these previously identified risk factors. Results from this project will provide a clear route for farmers to make the best decisions on Johne’s disease prevention.

Publications:

Meyer et al., 2018. A probabilistic approach to the interpretation of milk antibody results for diagnosis of Johne’s Disease in dairy cattle. Preventive Veterinary Medicine, 150, 30-37

Patterson et al., 2020. Mycobacterium avium paratuberculosis infection of calves – the impact of dam infection status. Preventive Veterinary Medicine.  In Press