Benefits of Johne's disease whole herd testing
Johne's disease is common on New Zealand dairy farms. It costs the industry between $40 million and $90 million every year in lost milk production and poor calving rates.
Our Johne's disease whole herd test identifies high-risk cows so you can make culling and other management decisions to minimise the spread of the disease. Regular testing combined with good management practices can:
- increase your herd’s productivity
- boost calving rates
- reduce the number of animals dying painfully from the disease.
About Johne's disease
Johne's disease is a chronic gut infection caused by the bacterium Mycobacterium avium paratuberculosis (MAP). Animals are infected in the first few months of life.
Johne's disease may lead to:
- lower milk production
- difficulty reproducing
- rapid weight loss
Infected animals stay healthy for several years and many never show the clinical symptoms of the disease — rapid weight loss and diarrhoea. Animals with clinical Johne's disease eventually die.
But even infected animals without clinical symptoms can produce less milk and have problems with reproduction. They can also spread the infection.
Some animals become what are known as super-shedders. Super-shedders pose the biggest risk to your herd. They show no clinical signs of the disease but excrete huge amounts of MAP in their faeces, making them extremely infectious. Super-shedders are likely to go on to develop clinical symptoms.
How Johne's disease whole herd testing works
Our whole herd test uses milk samples from a routine herd test to detect the antibody that shows an animal has been exposed to the disease-causing bacterium, MAP.
Whole herd testing for Johne's disease can identify super-shedders that are excreting large amounts of bacteria and putting your herd at risk.
When to test
You can test at any time of the year but we would recommend focusing on the 2nd or 3rd Herd test (November-March). Although you can test at the 1st or 4th herd test, please note false positives may occur if:
- Cows have recently calved (within 7 days of herd test)
- SCC is >1 million
- Low milk volumes - avoid testing too close to dry off or when part of the herd has dried off.
Most tend to test for Johne’s disease on the 3rd herd test (around February/March) to maximise the benefits and identify as many high-risk cows as possible so they can be culled before dry-off and calving.
The more regularly you test the more affected animals you will detect due to the slow, progressive nature of Johne’s disease. While it is not possible to detect early stage disease, testing annually will allow you to identify and cull animals that pose the greatest risk to your herd.
Test annually for best results
The more regularly you test the more affected animals you detect. Whole herd testing can’t detect animals in the early stages of Johne's disease with great accuracy, but annual testing allows you to detect and cull them in subsequent years as they start to pose a greater risk to your herd.
Getting the results
We send the results to your vet, who will work with you to develop a management plan to deal with high-risk animals and help stop the disease from spreading.
Blood testing for individual animals
We also offer a blood test to identify individual animals with Johne’s disease. You can use blood tests to confirm you have a problem with Johne's disease before going ahead with whole herd testing.
Your vet can take blood samples from animals showing symptoms of Johne's disease, or from a selection of animals to find out how widespread the problem is.
We need a 10ml blood sample from each animal being tested. We prefer purple top blood tubes, but will accept red top tubes.
Send the blood samples to our laboratory, together with a completed Animal Health Sample Submission form.
Tick Johne's disease ELISA to indicate the test you want.
Johne's disease testing prices