OJD prevalence status disputed

Reports by Haidee VandenbergheCountryman

The first abattoir survey for Ovine Johne's Disease (OJD) since WA's status for the disease changed has found just one test to be positive.

This calls into question the validity of the State-wide medium risk prevalence.

When WA's OJD status was revised last year, from low to medium prevalence, many growers were unhappy, claiming they did not have the disease and the classification would exclude them from premium interstate markets.

With funding from Animal Health Australia, Esperance-based ASHEEP recently finished a survey for OJD of more than 20,000 sheep slaughtered at the Shark Lake Food Group's Esperance abattoir between September and December.

The sheep came from 118 producers and just one positive incidence of OJD was found.

According to farm consultant Bob Reed, who also heads up ASHEEP's subcommittee on OJD, the positive result came from trade sheep from another area.

ASHEEP believes the abattoir survey results prove Esperance should not be lumped in with a State-wide category two OJD prevalence, but there is some dispute over how the results were calculated.

Despite there being just one positive case in this round of testing, two historical positive cases from several years ago were also included when deriving the region's OJD prevalence.

Overall, between 2008 and 2012, that gives Esperance an estimated 3.3 per cent prevalence for OJD infection in flocks.

An area must have less than one per cent to qualify as a low prevalence area.

Mr Reed said discussions clarifying the way the statistics were calculated is ongoing.

"We were disappointed in a way with how the statistics were undertaken," he said. "We are aware that one has already destocked and gone through a two-year quarantine and should have been declared clean."

Much of the argument over the rezoning of WA's status centres on market restrictions to other States but Mr Reed said the issue was not just about trade barriers - the industry needed more information about the distribution of the disease to protect those who did not have it.

"We want to look forward, not backwards, but we don't believe there has been a proper definition of where the disease lies," he said.

"What we have established is that for farmers in Esperance breeding sheep, it seems they have a very high clearance of OJD and we believe we're in a unique position to protect that. If you know you're clean and you know the danger is bringing infected sheep onto your property, then you can take on-farm security."

Last year ASHEEP, along with WAFarmers, called for specific zones in WA to better reflect where the disease was established.

But it's an argument that holds no traction with the Department of Agriculture and Food, which claims restrictions on sheep movements into a protected area and costs of assurance testing would result in few producers agreeing to meet the eligibility criteria of a protected area.

Mr Reed concedes zones may be harder to manage but he said there was little consultation with agricultural districts and growers without OJD were being penalised.

Fellow ASHEEP member John Wallace, who runs 5000 ewes at Neridup, said he wanted options when it came to protecting his property from OJD.

He is calling for mandatory Animal Health Statements to alert buyers to a seller's OJD status and more abattoir testing so farmers can be certain of their disease status.

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