Benefits of Johne's disease effluent testing
Johne's disease is common on New Zealand dairy farms. It costs the industry between $40 million to $90 million every year in lost milk production and poor calving rates.
Animal Health’s Johne's disease effluent test has been developed to offer a tool to identify if the bacteria responsible for Johne’s disease is present in the farm's effluent system. This test will give you an indication as to whether you have Johne’s bacteria present on farm.
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 clinical symptoms of the disease — rapid weight loss and diarrhoea. Animals with clinical Johne's disease eventually die.
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 effluent testing works
The test is comprised of four effluent samples taken from different areas of the effluent system. A PCR test is completed on all four samples and a detected or not detected result will be provided. This test is a tool to indicate that animals on farm may have Johne's disease and should be used as part of an overall Johne's disease management plan.
Getting the results
A test report will be emailed with 2 possible categories:
- Johne's bacteria Detected
- Johne's bacteria Not Detected
If Johne's bacteria is detected it is recommended that individual animal Johne's disease testing is completed using herd test milk samples. The individual Johne's disease test identifies between 80 -90% of animals in advanced sub-clinical stages of infection. These animals are often shedding high numbers of Johne's bacteria and are the biggest risk of transmission.
The collection of four solid effluent samples, representative of the current herd, from multiple locations of the effluent system is preferable. Locations may include the sand trap, sump, weeping wall or separator. Please refer to the submission form for further details on sampling. Johne's bacteria can survive within the environment for over 12 months and LIC advise to sample from locations that have been cleared out since the previous season.
Johnes’s disease effluent submission form
A negative effluent test is not a confirmation that a herd is free of Johne’s disease. To mitigate the risk of a false negative, appropriate samples must be collected which are representative of the whole herd at the time of sampling.
Animals go through fluctuations in shedding, so it is possible to miss infected animals if they are not shedding at the time of sampling. Repeated effluent testing is advised.
Johne’s bacteria could be present in effluent from infected animals no longer present in the herd. This is why it is important the samples taken are representative of the herd at the time of sampling.
During the early stages of infection, the effluent analysis may detect bacteria from animals who are shedding but who are not yet showing a measurable antibody response using the LIC Herd Test Johne’s disease product. Should this occur, continued monitoring of the herd, further effluent testing, and future whole herd testing is advised.
Speak to your vet to ensure you have a Johne's management plan in place.