How to best control Johne’s Disease in Cattle

March 27, 2020

Johnes Disease is affecting the production of Herds all around Ireland

We bring you another great article to ensure you help keep your Herd Healthy. Our consultant Vet looks at the impact of John’s Disease and how farmers can notice its effect on cattle. At Terra NutriTech, our aim is to always ensure your cattle get the exact nutrients and minerals they need. If you have any queries around your cattle health, please consult your Vet for professional advice.

What is Johne’s Disease and why should I be focused on looking out for it?

Johnes disease is a chronic disease affecting herds causing a range of symptoms and having a massive impact on production and performance of cattle.

It is caused by a bacteria called MAP (mycobacterium avium subspecies paratuberculosis). This bacteria will be ingested by young animals, typically calves and can lie dormant for years. We typically don’t see the symptoms of the disease before two years of age with symptoms not showing at an early age. This is an important consideration at the buying and selling stages of cattle trade.

What are the symptoms to look for?

We must remember Johne’s Disease is a chronic disease meaning that it progresses slowly even after calves being infected or ingesting the bacteria. Some older infected animals will show no symptoms but will still be shedding continuing the cycle on the farm. Typical symptoms include scouring, reduction of feed efficiency and weight loss. This drastically affects the absorption of nutrients due to the intestinal swelling caused by the bacteria.

Spreading across the Farm

An animal that is deemed positive for Johne’s will typically spread the bacteria in three ways:

  1. In faeces – in huge numbers which is the biggest risk
  2. In colostrum – to young calves and also in milk
  3. They may infect their unborn calf in the womb also

The young animals will typically ingest the bacteria in faeces or maybe colostrum. It will then go to the intestine where it will almost go into hibernation. In this state it also isn’t picked up by the immune system making testing impossible. It begins to reactivate in animals as they get older (usually in animals >2 years old). This continues the cycle with some showing symptoms as the disease progresses and also beginning shedding. It can have a massive impact on profit and performance.

What’s the best way to test cattle?

There are two critical elements to control, testing with a subsequent culling policy and controlling the spread on the farm (reducing the risk).

There are two main ways to test for Johne’s in milk or by blood sampling. With both these tests, we are checking for antibodies to the disease. This means that animals under two years of age are not tested as they may have been exposed but will be showing no evidence of the disease.

We also can use faecal testing to isolate the bacteria itself to confirm blood or milk test results.

Effectively Controlling the Risk

If we know the main spread is particularly by faeces, then milk and possibly in the womb to calves. We must work hard to reduce the risk of spread. Firstly with testing, we can identify the positive cows and take very specific risk management with them around calving.

When we have Johnes in our herds all these risks still need to be minimised for all stock.

For dairy calves, this is by snatch calving and avoiding things like pooling colostrum.

In the VIDEO, Tommy the Vet outlines why we need to get serious about Johne’s Disease and its spread. Focus heavily on regular yearly tests (60 days must be left for testing after TB testing) and culling policies. Then work hard on reducing the spread within the herd.