Assurance Based Credit (ABC) Scheme for OJD

The Assurance Based Credit (ABC) Scheme for OJD was introduced in July 2004. The ABC Scheme is used when trading sheep in Australia. Sheep to be moved or sold will be covered by a National Sheep Health Statement that will include the ABC score - the higher the score the more assurance you will have to protect your ovine Johne's disease status.  The National Sheep Health Statement will assist producers clearly identify the animal health status of sheep offered for sale.

What is the ABC Scheme?

The Assurance Based Credit (ABC) Scheme is a nationally agreed method of assessing the risk that sheep have OJD.

It builds on knowledge and hard-gained experience from the National Ovine Johne's Disease Program (NOJDP) to help sheep producers reduce the risk of their flocks becoming infected. It also provides a pathway for owners of infected flocks to improve their trading position by gaining trading credits through the use of a range of management tools.

On-farm management, through vaccination and grazing strategies will lower the risk of OJD spreading in sheep flocks should the infection be present or be inadvertently introduced. The combination of on-farm management and risk based trading is the best strategy identified by industry to minimise the impact of OJD.

Spelling out your ABC

All sheep sellers are able to declare their sheep's ABC score in writing on the National Sheep Health Statement.

Sheep buyers should make sure they obtain this information for any consignments they are interested in buying and learn what the ABC information on it means for them. Buyers themselves can then determine the risk those sheep present to their own flock, by relating the score of the sheep offered for sale to their own flock score, and determining whether they want to take that risk.

ABC is like 123.

Well it's more like 0 to 10...and there's some adding up involved.

Under the ABC Scheme, a sheep producer can claim credit points for his or her sheep under four categories. These are:

CATEGORY A. Area and flock of Origin - The known Johne's disease status of the flock or area in which the flock is located.

CATEGORY B. OJD testing history, including flock tests for the SheepMAP, as well as Abattoir 200 and Abattoir 700 testing

CATEGORY C. Vaccination history

CATEGORY D. Risk Assessment of consignment sheep

The numbers of credits assigned under each category is based on scientific risk assessment.

A consignment of sheep can have up to 10 credits in total. Each additional credit represents an approximate four-fold decrease in the risk that the sheep are infected. So sheep in a consignment with a score of 4 are about 64 times less likely to be infected than in a similar consignment of sheep with a score of 1 (that is, the difference of 3 credits means a difference in risk of 4 x 4 x 4 = 64).

So, by buying sheep with a high ABC score you can greatly reduce the risk that you will buy in OJD.

Keep these points in mind

• OJD can cost producers money in deaths and lost production as well as interfering with marketing restocker sheep.
• Use the ABC Scheme to take steps to reduce the risk that your sheep become infected or infect other people's flocks and to improve your trading options.
• Check the ABC status of any sheep you're interested in buying and ask to see the National Sheep Health Statement before you agree to buy. If you're confident in the declaration, buy sheep with a high ABC score.

By purchasing sheep with a high score you are protecting your sheep from ovine Johne's disease, your flock's status and your own ABC score. You are also protecting your neighbours.

OJD management when purchasing sheep is as simple as ABC. Just follow these three steps

Ask for a National Sheep Health Statement and only consider buying the sheep if you're happy with it.

Buy sheep with a higher score than your own flock's score.

Check the vaccination and testing history, OJD and MAP status of flocks. Complacency will keep OJD spreading and costing.

The higher the score the lower the risk.

Introducing lower score sheep

The principle of flock-based assurance and the ABC is that a producer should only introduce sheep with the same or, preferably, a higher ABC score than the highest score sheep in their flock. The more a producer has to lose if their flock becomes infected, the higher the ABC score sheep they should buy.

Introducing lower score sheep may affect the risk associated with a flock depending on the type and number of sheep introduced. So producers who have introduced lower score sheep to their flock in the previous two years have to note this on the Animal Health Statement. This is to alert buyers to seek additional information if they are interested in buying the sheep.

Terminal Lambs

Young sheep are unlikely to spread OJD and so lambs that meet the criteria for Terminal Lambs may be traded without restriction as long as they are slaughtered before cutting any adult teeth.

Terminal Lambs are:

• young crossbred wether and ewe lambs,
• identified by an approved NLIS (Sheep) Terminal Lamb eartag, and
• that will be slaughtered before cutting any adult teeth.

If Terminal Lambs are kept in the flock after cutting their first adult teeth, the flock will be at risk of infection and therefore its score under the ABC Trading Scheme would be affected.

Terminal Lamb Fact Sheet (49 KB)

Page Updated: 9 July 2010