Is Eradication Of OJD Viable?

February 4, 2000 The Rural News

A national ovine Johne's disease (OJD) research trial, now underway, should answer some

key questions about the feasibility of eradicating OJD from infected properties.

The project will investigate whether removing infected flocks from a property and allowing for the environmental decontamination of pastures will eradicate OJD.

New South Wales OJD co-ordinator Ian Links said the trial would also determine whether this type of strategy is an economically viable option for individual sheep enterprises.

The research project is to be conducted over six years as part of the National Ovine Johne's Disease Control and Evaluation Program (NOJDP).

While NSW Agriculture is the lead research body, scientists and livestock specialists from around the country will lend their expertise. Dr Links said up to 50 infected properties from NSW, Victoria and South Australia will participate in the trial, implementing a property disease eradication plan and destocking all infected sheep.

"The properties will remain unstocked for 15 months, including two consecutive summers, the period thought adequate for full decontamination of the OJD bacteria on current knowledge," said Dr Links. "Two consecutive summers is possibly a conservative estimate and concurrent research is investigating whether one full summer may be adequate for decontamination purposes.

At the end of the 15-month period, each property will be restocked with "clean" sheep which should be sourced from Market Assurance Program (MAP) flocks or flocks that have been tested to MAP equivalence.

Monitoring for an signs of OJD in the new sheep will continue for a minimum of three years.

"We have selected properties from a wide geographical area to cover a range of different environments, sheep breeds and enterprises." said NSW Agriculture OJD research co-ordinator, Dr David Hall.

"Our aim is to test the destocking and decontamination strategy under normal commercial operating conditions so that, if successful, the results can be extended to the sheep industry."

Dr Hall said the properties would be able to pursue alternative business options during the 15 month unstocked period, for example, increased cropping, cattle grazing, raising lambs for slaughter or running "clean" sheep for slaughter within 12 months.

Economies will also make a full assessment of the economies of property disease eradication plans." Dr Hall said. State sheep industry funds are being used to provide additional financial assistance to NSW producers participating in the trial. The combined assistance package will help cover the cost of drawing up property disease eradication plans. destocking and restocking, and additional work and tests associated with participating in the trial.