Stephen Love, State Coordinator - Internal Parasites, NSW DPI, Armidale
There are two ways you can get drench-resistant worms: breed your own and/or buy someone else's.
Here is advice on quarantine treatments from the revised material developed for the new WormBoss (to be launched soon):
1. Quarantine drench all sheep new to the property.
2. Quarantine the sheep after treatment.
3. After quarantine, release the sheep onto a paddock that is likely to be contaminated with worm larvae due to grazing by other sheep. This will dilute (lower the proportion of) resistant worms surviving treatment with worm larvae already on your property.
4. WormTest the imported sheep 10–14 days after drenching for added confidence that treatment was successful.
5. Get expert advice on up-to-date recommendations for quarantine treatments. These will evolve as the drench resistance picture changes.
Monepantel and Derquantel each represent new drench groups. In Australia, monepantel was released in September 2010 as Zolvix®. Derquantel is not yet released in Australia.