A vaccine against OJD called Gudair® is registered for use in sheep in Australia. This vaccine is a valuable management tool to help control the spread of the disease but is not a “silver bullet” . The vaccine does not prevent infection entirely, however it does significantly reduce the number of sheep that die from OJD and in most flocks, decreases the amount of bacteria passed in the dung. This reduces environmental contamination and provides less opportunity for disease transmission.
It is important to remember that vaccination is not 100 per cent effective. Some vaccinated sheep may develop ‘subclinical’ OJD infection and shed bacteria in their dung without showing obvious signs of illness. Some vaccinated sheep will eventually develop severe ‘clinical’ OJD and may shed very large quantities of bacteria on the pasture before they die. Any sheep showing signs of wasting should be immediately culled to reduce pasture contamination.
Effective prevention and control of OJD requires a multi-pronged approach of vaccination, abattoir monitoring/testing, purchasing and selling sheep with high assurance declared on the national Sheep Health Statement.
Using the Vaccine
The Gudair® vaccine can be administered to sheep from four weeks of age. It is an inactivated (killed) vaccine so there is no risk that vaccination will introduce OJD into uninfected flocks. A single 1mL dose is given, most commonly at lamb marking. It is recommended that lambs are vaccinated before 16 weeks of age. Booster doses are not required.
Injection site reactions are common with Gudair® and it is important to administer the dose under the skin high on the neck behind the ear. Animals should be adequately restrained during vaccination. Young lambs should be vaccinated in a lamb marking cradle. Weaners, hoggets and adult sheep should be packed tight in a race and have their heads held high to ensure the vaccine is delivered at the correct site. Vaccinated sheep must be identified with a NLIS (sheep) tag that contains the property identification code or number and the letter ‘V’.
More information is available on the fact sheet titled ‘OJD Vaccination – What you should know’ (PDF 482 kb)
Precautions When Vaccinating Against OJD
Producers and veterinarians should be aware that accidental self-injection with the OJD vaccine, Gudair® can cause a severe and persistent reaction. Vaccinators should be trained in correct vaccination technique and safe handling of vaccinating equipment. For further information contact your animal health advisor or Zoetis on 1800 ZOETIS – 1800 963 847.
More information on the safe use of the Gudair vaccine is available on the fact sheet titled ‘Gudair Vaccine – User Safety Information’ (PDF 144 kb)