Vaccinating Sheep against Ovine Johnes Disease

Note Number: AG1133
Published: September 2006
Updated: September 2009

 

The vaccination of sheep provides a useful tool to assist in protecting flocks from the effects of ovine Johnes disease (OJD).

Why vaccinate?

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 Ô 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%.

All flock owners should aim to purchase sheep with a low risk of being infected with OJD. The Assurance Based Credit (ABC) Scheme provides credit points for sheep vaccinated against OJD. These points contribute towards the ABC score of a mob of sheep. Purchasing sheep with a higher score will decrease the chance of purchasing infected sheep. (Refer to Agriculture Note: Assurance Based Credit (ABC) Scheme and Sheep Health Statements).

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 veterinary consultant or Department of Primary Industries (DPI) animal health staff.

Flocks may be considered suspected to be infected if they neighbour an infected flock, sheep have been purchased from or sold to 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 or DPI animal health staff.

Most flocks in Victoria are classified as Nil Assurance. This means they are not known or suspected to be infected with OJD. Owners of Nil Assurance flocks should consider a number of factors prior to embarking on an OJD vaccination program. These include:

• 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 store sheep,
• whether store sheep are sold or moved interstate,
• 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, and
• 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 and are eligible for a credit point towards their ABC score. 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 and gain an increase in their ABC score, a SheepMAP veterinarian must certify they were vaccinated prior to exposure to the OJD 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.

Do I have to ear tag vaccinated sheep?

All sheep vaccinated against OJD must be identified with an approved National Livestock Identification System (Sheep) (NLIS - Sheep) V ear tag. The NLIS V ear tag has a capital V in a circle  on the opposite side of the ear tag to the Property Identification Code (PIC) and NLIS logo. Vaccinated sheep may previously have been identified by a three hole ear punch in one ear. This form of identification is no longer approved.

Is the vaccine safe to use?

Accidental self-injection with Gudair™ vaccine may result in side effects and a local 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. A list of businesses that stock Gudair™ can be found at  Pfizer Animal Health web site. 

Owners of flocks that are infected, or flocks that have undergone testing due to suspicion of infection, may be eligible for a vaccine subsidy and should contact DPI animal health staff to determine their eligibility for the subsidy.

For further information

Further information about OJD can be obtained from animal health staff at your nearest DPI office or on the DPI web site:

Acknowledgements

This Agriculture Note was developed by Dr Alison Lee, Biosecurity Victoria Animal Standards Branch Sept 2006.

It was reviewed by Dr David Champness, Biosecurity Victoria Animal Standards Branch Sept 2009.