Paratuberculosis (Johne’s Disease)

This post was written by

Eamon Guinevan MRCVS| Veterinary Surgeon at McLaughlin’s Veterinary Clinic

Calving season has already started. We need to be aware of Paratuberculosis Johne’s disease and the risk of spread at this time.

For those that dont know Johnes disease, it is a bacterial disease of cattle and other ruminants for which there is no cure. It is caused by the bacterium Mycobacterium avium subspecies paratuberculosis (MAP), hence the other name for the disease Paratuberculosis.

It is a disease of adult cattle resulting in:

• Reduced production: lower milk yields & lower feed conversion rate
• Weight loss
• Scour and emaciation followed by death

The most common time for an animal to get Johnes is during its first six months of life. Calves can be affected at birth when the mother has the disease. More often than not the calf gets Johnes by bacteria from contaminated sources. When a calf drinks or eats contaminated food or milk this is when they get Johnes. Even the smallest amount of dirt/dung on a cows udder when the calf is suckling can cause them to have the disease.

To minimise the spread of Johnes Disease an action plan should be put in place.

• Removing the calves from the calving pen as soon as possible when they are born is crucial in order to reduce the risk of infection. By carrying this out, the risk of calves attempting to suckle from a cow with a dirty udder is reduced.
• It is important to maintain hygiene levels within calving pens. Calving pens should be frequently and thoroughly cleaned.
• Disinfectants can be used to get rid of any unwanted bacteria.
• Sufficient fresh bedding should be put down between calvings to ensure that the pen floor is dry and clean.
• It is important to wash your hands and ensure that the feeders, tubes and buckets that come in contact with the cow’s first milk are carefully washed between each use.
• It’s best to feed colostrum and milk from cows that have tested negative for Johnes.
• Heifer calves should be fed with replacer after the first few feeds.
• New testing for Johnes disease: can be done on milk, blood or faeces.
• Any positive animals should be selected for culling and kept away from calves until such time as they leave the farm. By the time an infected animal tests positive it is likely that they will be shedding the bacteria in dung and milk.
• These animals should be prioritised for culling since while they remain in the herd they can spread the disease. Please speak to your vet on the above issue.