The WormBoss worm control program for sheep in the non-seasonal rainfall region has five components that are effective when used in combination. Their effectiveness is reduced when not used in an integrated way.
Open the complete program (PDF)
A summary of the components is below (see further chapters in the PDF for details).
1. Use grazing management to create low worm-risk paddocks
- Prepare low worm-risk paddocks for lambing and weaning by preventing contamination with worm larvae in the 2 to 5 months before they are needed. (For the number of months required for your location, refer to the table on page 5 of the PDF and also at Grazing management). In this time, spell paddocks, graze with sheep up to 21 days after the protection period (when it is killing worms) of an effective drench1, or graze with cattle.
- Use ‘Smart grazing’ to prepare winter weaner paddocks.
2. Breed and feed for worm-resistant sheep
- Use rams with better than average worm egg count (WEC ASBVs2) and, if applicable to your area, less dag (DAG ASBVs); choose the more negative values for both.
- Maintain good nutrition to enhance the sheep’s immunity to worms.
3. WormTest at recommended times
- From March till October, WormTest 4–6 weeks after significant rain that has follow-up rain, including the autumn break.
- Young sheep in May/June before the more severe winter weather arrives.
- Pre-lambing (also include a larval culture to identify the worm types present).
- A week prior to other management activities (such as crutching, joining, shearing and weaning).
- WormTest at 6–8 week intervals after a short-acting drench was given. If using a persistent drench (including capsules and injections) then see ‘Effective use of long-acting drenches’.
- And at other non-routine times as described in the Drench Decision Guide for this region.
4. Drench3 at recommended times
- The ‘first summer drench’. All sheep receive this when pastures are haying off in late spring. In very dry or drought years do a WormTest beforehand, as even this drench may be unnecessary and may cause increased selection for drench resistance.
- Lambs at weaning. This may coincide with the ‘first summer drench’. Autumn-drop lambs may also need an additional drench 4-8 weeks after weaning.
- Drench all introduced sheep with a combination of no less than 4 unrelated drench groups with at least one of these being the newest drench actives: monepantel or derquantel4.
- Drench sheep showing obvious signs of worm-related illness.
- At other times, use the Drench Decision Guide to make drenching decisions.
5. Manage drench resistance
- Conduct DrenchTests every 2–3 years. Use DrenchCheck-‐Day 14 between DrenchTests.
- Avoid unnecessary drenching.
- Use effective drenches and multi-active4 combinations where possible.
- Use short-acting treatments. Reserve long-acting products for specific purposes or high worm-risk times.
- Rotate among all effective drench groups4 for each mob (and each paddock where possible).
- Calibrate your drench guns, dose to the heaviest sheep and follow label instructions.
1This drench must be tested and shown to be highly effective on your property
2ASBVs=Australian Sheep Breeding Values.
3Drench refers to anthelmintics regardless of route of administration
4Drench groups are the chemical family to which an ‘active’ belongs. An ‘active’ is the chemical in a drench responsible for killing worms. Some drenches contain more than one active and are called ‘multi‐active’ or ‘combination’ drenches. See Appendix: Drench groups and actives.
This is an up-to-date, integrated regional worm control program for sheep in the non-seasonal rainfall region of New South Wales. It builds upon earlier programs (including from the NSW Department of Primary Industries) and accumulated knowledge, as well as new information from the Integrated Parasite Management in Sheep project, funded by Australian Wool Innovation.
The program aims to improve the profitability and welfare of your sheep through
- fewer deaths and illness from worms
- fewer drenches, particularly long-acting drenches
- improved productivity
- prolonged life of drenches