Ovine Johnes disease has caused significant sheep losses in the past but is being detected in less animals inspected as part of the National Sheep Health Monitoring Project.
This trend comes out of the data collected from the 1-1.5million mutton sheep inspected every year as part of the monitoring project.
It indicates the level of OJD infection in Australian sheep flocks has declined.
But Animal Health Australia’s biosecurity manager Rob Barwell said while the big picture may look promising, there was always work to do in managing this disease.
‘‘The data we have gathered over the past 10 years has shown us that infection levels in inspected sheep lines have demonstrated a downward trend in all states,’’ Dr Barwell said.
‘‘However, there are some regions that have not shown the same level of decline, which means we need to get the message out there to all sheep producers to improve their management practices to manage the disease on-farm or avoid it coming onto their farms.
‘‘At this stage, we are attributing the reduction in infection levels to a strong take up of the OJD vaccine (Gudair), which is one, but certainly not the only, tool to help manage the disease.
‘‘Producers do need to keep using the vaccine, even when they’re not seeing cases on-farm; it can re-emerge if stopped.
‘‘It is important to remember that OJD usually enters a flock through the introduction of infected sheep or stray animals.
‘‘Sheep droppings and contaminated run-off can also spread the infection between farms once it has seeded into an area, and the risk of spreading infection via natural waterways and floodplains is also present.’’
Dr Barwell provided five key biosecurity tips for sheep producers to help avoid OJD in their sheep:
■Know your own flock’s disease status.
■When buying sheep make sure you ask for and use the information on a Sheep Health Statement.
■Develop a biosecurity plan to minimise risks.
■Ensure that your boundary fences are secure and in good order to help prevent neighbours’ sheep straying onto your property.
■Continue to monitor for the disease on-farm and through abattoir monitoring.