WormBoss worm control program

Qld/NSW Summer rainfall/tablelands and slopes

Program summary

The WormBoss worm control program for the summer rainfall/tablelands and slopes region has five components that are most effective when used in combination.

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 spring lambing paddocks by preventing contamination with worm larvae in the 6 months prior to lambing
    • March and April: spell paddocks, graze with cattle or graze with sheep for up to 21 days after the protection period (when it is killing worms) of an effective drench1.
    • May–August: no grazing restrictions apply when maximum daytime temperatures are consistently below 18°C, if they are not then use the same strategy as for March and April.
  • Prepare summer weaning paddocks by preventing contamination with worm larvae in the 3 months prior to weaning:
    • Spell paddocks, graze with cattle or graze with sheep for up to 21 days after the protection period (when it is killing worms) of an effective drench1.

2. Breed and feed for worm-resistant sheep

  • Use rams with better than average worm egg count (WEC ASBVs2); choose the more negative values.
  • Maintain good nutrition to enhance the sheep’s immunity to worms.

3. WormTest at recommended times

  • WormTest before these routine opportunities to drench:
    • Pre-shearing.
    • Pre-lambing marking (ewes).
    • Pre-weaning (ewes).
  • Weaning to shearing: WormTest at 4–6 week (summer) or 6–8 week (winter) intervals after a short-acting drench. If using a persistent drench then see ‘Effective use of long-acting drenches’.
  • And at other non-routine times as described in the Drench Decision Guide.

4. Drench3  or use Barbervax® at recommended times

  • If using Barbervax, follow the prescribed program (see ‘When to WormTest and when to drench or use Barbervax®’)
  • Drench breeding ewes pre-lambing (as they temporarily lose their immunity).
  • Drench lambs at 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 individual sheep showing obvious signs of worm-related illness and WormTest the mob.
  • 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.
  • In general, use short-acting treatments with 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.
  • Use of Barbervax® vaccination should slow the rate of development of drench resistance.

1This drench must be tested and shown to be highly effective on your property
2 ASBVs=Australian Sheep Breeding Values.
3 Drench refers to anthelmintics regardless of route of administration
4 Drench 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 summer rainfall/tablelands and slopes region of New South Wales and southern Queensland. It builds upon earlier programs (including from the state departments of primary industries: NSW DPI and Qld DAFF) and accumulated knowledge, as well as new information from the Integrated Parasite Management in Sheep project, funded by Australian Wool Innovation and the Sheep CRC.

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), Lewis Kahn (UNE), Stephen Love (NSW DPI), Maxine Lyndal-­Murphy (Qld DAFF), Steve Walkden-­Brown (UNE)

Sheep CRC wish to acknowledge the major contribution to this publication from the NSW DPI program: WormKill and the Qld DAFF program: Wormbuster, as well as research from the CSIRO McMaster Laboratory and The University of New England.

September 2015

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. ParaBoss and the University of New England 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. ParaBoss and the University of New England make 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’). ParaBoss and the University of New England 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 ParaBoss.

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

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