Adult cattle are less prone to a new infection compared to young stock, which are highly susceptible. Calves that ingest high doses of Johne’s bacteria are more likely to develop Johne’s disease earlier in life.
Johne’s bacteria can survive for several months in the environment under damp, dark and cool conditions, and therefore can survive in effluent, water and on pasture.
It is important to remember that Johne’s bacteria in the environment comes from infected animals. Johne’s bacteria survives long periods in faeces and effluent.
Wind drift during effluent spraying may spread Johne’s bacteria to nearby paddocks and can represent a significant risk to calves.
Any pastures irrigated with effluent should never be used for young stock. Once Johne’s bacteria is on pasture, it is difficult to eliminate, therefore focus should be on reducing the risk.
Johne’s Disease risk management primarily revolves around protecting calves from infection by Johne’s bacteria. It may be impossible to prevent all contact with faeces and other sources of Johne’s bacteria, so it is important to limit exposure.
For more information or on managing Johne’s contact your local Franklin Vets Clinic.
Dr Jordan McGimpsey – Farm Vet at Franklin Vets Taupiri