Vaccinating sheep against Ovine Johne's disease
Note Number: AG1133
Published: September 2006
Updated: December 2010
The vaccination of sheep provides a useful tool to assist in protecting flocks from the effects of ovine Johne's disease (OJD).
Sheep owners may choose to vaccinate their flock to: assist to control OJD if the flock is infected, assist in preventing the introduction of OJD into an unaffected flock, and/or provide extra assurance to purchasers of sheep, including rams that they are low risk of being infected.
Trials conducted under the national OJD program have produced data on the effectiveness of the Gudair™ OJD vaccine, the only OJD vaccine currently available for use in sheep in Australia.
Trial results indicate that Gudair™ vaccine can reduce the number of deaths due to OJD by 90%, and reduce the amount of OJD-causing bacteria excreted in sheep manure by 90%.
Who should vaccinate?
Vaccination is recommended for most infected flocks and any flock at risk of infection. Owners of infected flocks should discuss the strategic use of vaccine with their veterinarian.
Flocks may be at high risk of infection if they neighbour an infected flock, sheep have been purchased from an infected flock, or infected sheep have been detected during abattoir monitoring.
Owners of these flocks are also encouraged to discuss their individual situation with their veterinary consultant.
Other factors owners of flocks should consider prior to commencing an OJD vaccination program are:
- the type of sheep enterprise they run (eg wool, meat, stud)
- how often sheep are introduced into the flock, and the number of different source flocks sheep are purchased from
- whether they sell non-slaughter sheep
- whether OJD has been detected in their district
- the condition of boundary fencing
- local topography and drainage onto their property
- the cost of the vaccine
- safety issues associated with vaccine use.
SheepMAP flocks are those that have tested with negative results and have management in place to assist in preventing the introduction of OJD into their flock.
Many of these flocks are also choosing to vaccinate in order to provide extra assurance that OJD is not present in their flock.
How do I vaccinate my sheep?
It is recommended that sheep are vaccinated as lambs, between 4 to 16 weeks of age. All lambs vaccinated between 4–16 weeks of age are considered 'Approved Vaccinates'. Sheep only require one vaccination for their lifetime.
Sheep over 16 weeks of age can also be vaccinated. However, for them to considered 'Approved Vaccinates' a SheepMAP veterinarian must certify they were likely to have been vaccinated prior to exposure to the OJD-causing bacteria.
The only recommended site for vaccination with Gudair™ vaccine is under the skin (not in the muscle), high on the neck, behind the ear. Gudair™ vaccine may cause a lump at the site of vaccination in some animals. Vaccination at this site reduces the risk of this lump downgrading the value of the carcass at slaughter.
Is the vaccine safe to use?
Accidental self-injection with Gudair™ vaccine may result in side effects and a severe inflammatory reaction in some people. To reduce the risk of accidental self-injection, sheep should be suitably restrained. The product leaflet should be read carefully before use.
Where can I obtain vaccine?
Gudair™ vaccine can be obtained from veterinarians and rural merchandisers who have been approved to sell the vaccine.
For further information
This Agriculture Note was developed by Dr Alison Lee, Biosecurity Victoria, Sept 2006.
It was reviewed by Dr Alison Lee, Biosecurity Victoria, in July 2011.