18 May 2016
Johne’s disease solutions available
Help is at hand for dairy farmers facing a problem with Johne’s disease in their cattle.
LIC is reminding farmers of the options available from their herd improvement co-operative to help them manage the
disease, including diagnostic testing and a comprehensive Johne’s disease management guide developed by experts.
“We know Johne’s disease can be a stressful and frustrating challenge for many dairy farmers,” LIC GM Biological Systems
Geoff Corbett said. “We want to make sure farmers know there are tools available that can help them manage the disease
in their stock.”
While there is no cure for Johne’s disease in cattle, taking advantage of testing services available and implementing a
management plan can make all the difference to cow losses and the longer-term health of the herd, Corbett said.
“We have been having a lot of success in New Zealand with this approach. LIC has been screening more than 100,000
animals a year with our Johne’s disease diagnostic testing for a number of years. This supports farmers with a Johne’s
disease problem to identify and remove problem cows with advancing infection that are shedding the bacteria and before
they develop clinical disease.”
In the last few years a joint venture of organisations including LIC and DairyNZ, working together as the Johne’s
Disease Research Consortium (JDRC), has carried out a range of work to develop and share disease management tools for
farmers. The consortium has funded a significant longitudinal study conducted by the animal health laboratory at LIC, as
well as research into approaching Johne’s disease from a genomics standpoint.
Outcomes of this work have included the creation of the testing regime available to farmers now, which uses milk samples
from the herd testing process run by LIC.
“This testing has proved very popular with farmers, with the ease of being able to use the herd test milk sample. All
they have to do is schedule Johne’s disease testing for the same time as herd testing and the LIC diagnostics laboratory
does the rest. Vets follow up with results and help with ongoing management plans for the farmer,” Corbett said.
While clinical Johne’s disease mostly affects older animals, it is calves and young stock that are most susceptible to
infection. With other management interventions, regular testing and culling can effectively protect the replacement
heifers against Johne’s disease and also immediately reduce losses due to clinical Johne’s disease among the adult herd.
If farmers screen and cull in autumn before calving they can reduce to a minimum the number of cows dying with Johne’s
disease during and after calving. This is a big benefit to farmers. It removes cows that will become clinical - before
they become clinical - and protects the calves being born.
A Johne’s disease management guide was developed by the consortium for farmers, with the latest and best advice on
managing the disease. It is available from DairyNZ’s website and has also been distributed to many vets.
“Using the measures in the management guide in conjunction with testing will help farmers reduce the impact of Johne’s
disease in their herd and bring it under control,” Corbett said.
The management guide includes information on how to recognise the disease, what causes it, how it is transmitted, which
animals are most at risk and steps to take.
Advice in the Johne’s disease management guide includes the following:
• Develop a practical long-term Johne’s disease risk management plan with the help of your vet.
• Test the herd and cull high risk cows and heavy shedders before calving.
o This will reduce exposure of calves to Johne’s bacteria at birth.
o Note that the stress of calving and milking will often push cows with advanced infection “over the edge” to become
clinically sick and die.
o Johne’s testing herd-test milk samples is a simple and efficient option to screen the milking herd.
• Limit calves’ exposure to faecal matter, including keeping them out of effluent paddocks.
• Limit calves’ exposure to adult cows because adult cows pass on the disease (e.g. send your replacement heifers to a
rearing unit with no adult cows or other adult ruminants as soon as possible after weaning).
• Be vigilant when buying new stock to guard against introducing Johne’s disease to your herd.
"The tests are extremely useful in notifying high risk animals and ‘super shedders’ – these animals are high
transmitters,” Corbett said.
“The super shedders or cows with advanced Johne’s disease will excrete copious amounts of the bacteria into the
environment , if they are pregnant, then chances are their offspring will also be born with Johne’s disease, thus
continuing the cycle.
“Removing them reduces the transmission to other animals. The objective of the testing and management regime is to break
the transmission cycle and infection of young stock,” Corbett said.
“Successful management of Johne’s disease won’t be an overnight process, but vigilance with the management principles in
the management guide and appropriate testing will address the impacts of Johne’s disease in affected herds.”
ENDS