WormBoss worm control program

NSW non-seasonal rainfall

Program summary

The WormBoss worm control program for 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.

A summary of the components is below (click on the headings below for more information):

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. (Click here for the number of months required for your location). 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 dagginess (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, 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 if barber’s pole worm have been a problem in the past year).
  • Prior to other management activities (such as crutching, joining, shearing and weaning).
  • At 6–8 week intervals after a drench was given.
  • And at other non-routine times as described in the Drench Decision Guide.

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 8 weeks after weaning.
  • Drench all introduced sheep with a combination of no less than 4 unrelated drench actives with at least one of these being the newest drench actives: monepantel (Zolvix®) or derquantel (with abamectin—Startect®)4.
  • 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-Day10s between DrenchTests.
  • Avoid unnecessary drenching.
  • Use effective drenches and multi-active4 combinations where possible (those shown to be highly effective on your property).
  • In general, use short-acting treatments and restrict the use of long-acting products only for specific purposes or high worm-risk times
  • 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 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


Deborah Maxwell (Sheep CRC) and Stephen Love (NSW DPI), with contributions from Dan Salmon (Riverina LHPA), Jim McDonald (Tablelands LHPA), Bill Johnson (Tablelands LHPA), Tony Morton (Hume LHPA) and Belinda Edmonstone (Lachlan LHPA).

The Sheep CRC acknowledges the major contribution to this publication from the NSW DPI program, ‘DrenchPlan’, which was developed as a cooperative venture involving:

  • NSW Department of Primary Industries—veterinarians, parasitologists and livestock officers.
  • Livestock Health and Pest Authorities, NSW (formerly Rural Lands/Pastures Protection Boards)—District Veterinarians
  • CSIRO Division of Animal Health—research scientists

With assistance also from the private sector including primary producers, pharmaceutical companies and consultants.

June 2012

Each regional ‘WormBoss worm control program’ has been developed from local research results and experience proven to be relevant and successful for most farms in the region. Sheep CRC acknowledge that this is not the only method of worm control in the region and more refined programs can be developed in consultation with your worm management advisor/veterinarian using information and knowledge specific to your property and sheep.

Future events cannot reliably be predicted accurately. Sheep CRC makes no statement, representations or warranties about the accuracy or completeness of, and you should not rely on any information relating to the ‘WormBoss worm control program’ (‘Information’). The Sheep CRC disclaims all responsibility for the Information and all liability (including without limitation liability and negligence) for all expenses, costs, losses and damages you may incur as a result of the Information being inaccurate or incomplete in any way for any reason.

No part of this publication is to be reproduced without the permission of Sheep CRC Ltd.

© Sheep CRC Ltd 2012 (ABN: 12 125 726 847)