This strategy describes when to use strategic drenches and how to decide when tactical/therapeutic drenches are needed.
For those who like to see all the information and simply read through it in order. Each heading is a link to a page of information—the dot point provides a summary of the page.
Tip: Keep this page open and open the links in new tabs.
NSW Non-Seasonal Rainfall: When to test and when to drench
The times for routine worm testing and drenching in this region. Not all testing or drenching is routine; other times to do these are recommended by the Drench Decision Guide, according to details you provide about your mob of sheep.
NSW Non-Seasonal Rainfall: Drench Decision Guide
This tool recommends whether a mob should be drenched, the length of protection warranted and when to worm test again. It is your day-to-day tool on drenching decisions that should be used in conjunction with the annual program of routine testing and drenching times.
The DDG tool steers you through a series of questions about your sheep; choose the answer that applies to your mob (or make up your own scenario).
For those who prefer a problem based approach to learning, answer the following questions.
Each of the questions below links further down the page to the answers.
You can also click on each question below to go to WormBoss pages with related information.
1. What is the purpose of a strategic drench?
Strategic drench: a drench given at a critical time to sheep that are susceptible to worm infection (e.g. weaners and pre-lambing ewes) and also given at times to reduce worm larval contamination of a pasture grazed by the drenched sheep over the following weeks or months. The sheep themselves may have had a low worm egg count at the time of this pre-emptive treatment.
In this region there are 2 times when sheep should be drenched in most years without a prior WormTest. These are:
All sheep receive this when pastures are haying off in late spring/early summer). In dry or drought years do a WormTest beforehand as a drench may be unnecessary and could cause increased selection for drench resistance. In the eastern Riverina, this could be delayed until immediately post-harvest and be based on a WormTest.
This may coincide with the ‘first summer drench’. Weaned lambs are highly susceptible to worms, especially from the stress of weaning. There may also be high worm-risk in wet seasons.
Drenching will help weaners to achieve the growth rates needed for survival. Autumn-drop lambs may also need an additional drench 8 weeks after weaning. For spring-drop lambs, additional drenching after weaning should be done on the basis of WormTest results.
3. The online Drench Decision Guide (DDG) for NSW Non-Seasonal Rainfall assists you to decide whether a mob of sheep should be drenched now and when to test again. Open the DDG and answer the questions it offers based on the scenario (from below) that you are using. Try at least three of the following scenarios.
Links to the learning topics for NSW Non-Seasonal Rainfall