Not sure how to stay on top of Johnes? Follow this testing framework!
Johne's disease (JD) presents a unique challenge for producers and veterinarians as the virus has a long incubation period, therefore clinical signs and shedding are typically only seen in adult cows. Calves and young stock are particularly susceptible to infection however, the presence of the disease is hard to detect in it’s early stage as the bacteria can remain ‘hidden’ in the gut with little or only intermittent shedding. The aim of Johne's disease management is to identify and remove animals likely to be shedding.
Here we provide a suggested Johne's screening protocol for vets to implement and work through with farmers.
Spring calving herds. The aim here is to identify and cull high-risk animals before calving.
Based on clinical disease, herd prevalence, management practices (to minimise MAP transfer to young stock) and aims for testing. If the aim is to lower prevalence in the herd then the indication would be to cull. If the aim is to decide which cows to cull, depending on other factors (animal value, productivity etc) the decision may be reasonably made to cull other animals first.