Online learning: Qld/NSW Summer Rainfall / Slopes and Plains—Deciding when to drench and what drench to use
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.
Qld/NSW Summer Rainfall / Slopes and Plains: 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.
Qld/NSW Summer Rainfall / Slopes and Plains: 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).
Question and answer
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.
- What is the purpose of a strategic drench?
- Which classes of sheep receive a routine (strategic) drench, and when?
- The online Drench Decision Guide (DDG) for Qld/NSW Summer Rainfall / Slopes and Plains 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.
- Weaners in May that received a combo drench into a prepared winter weaner paddock about a month ago, less than 5% are scouring, an egg count shows 80 epg.
- Weaners in late January that were drenched with Monepantel at weaning in early December. There are no signs of scouring and they look healthy.
- Ewes in November. No drench was required before lambing. About 15% are scouring.
- Ewes received a first summer BZ/LEV/ML drench in early December, it is now mid January. Summer has been unusually wet. Sheep are not scouring but a couple of ewes were found dead in the paddock and others are lagging during mustering.
- Late-lambing ewes in good condition just prior to being moved to their lambing paddock. A worm egg count shows 350 epg.
- Lambs just about to be weaned, they look well-grown with no obvious signs of worms.
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.
2. Which classes of sheep receive a routine (strategic) drench, and when?
- If the grass is green and actively growing in these months:
All sheep should be given an effective drench for barber’s pole worm, scour worms and nodule worm. However, if a WormTest (recommended before drenching) is greater than 500 epg, and seasonal conditions are good, your sheep may need extra protection against barber’s pole worm, such as a mid-length or long-acting drench (if effective on your property).
If a persistent product is used, the sheep can be kept on the same pasture or moved elsewhere according to your management needs. If a short-acting drench is used, move sheep to low worm-risk pastures with good feed. WormTest in 4–6 weeks after a short-acting treatment. If mid-length or long-acting treatments are used, follow the recommendations for mid-length and long-acting treatments.
- If the grass is brown or not actively growing in these months:
Young sheep (less than 18 months old) will need an effective short-acting drench against barber’s pole worm, scour worms and nodule worm. WormTest in 4–6 weeks after the drench.
At weaning: This may coincide with the October/November drench, if not, always drench at weaning.
3. The online Drench Decision Guide (DDG) for Qld/NSW Summer Rainfall / Slopes and Plains 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.
- Ewes in mid-pregnancy are in Condition Score 3 with 500 kg/ha of green herbage mass; their last drench was a short-acting combination. A WormTest shows an average count of 900 epg with 85% barber’s pole worm.
- Weaners injected with long acting moxidectin in mid-February (after a short acting drench at late December weaning). It is now late-March and the weaners look good.
- Ewes just prior to lamb marking, they were drenched with a short-acting combo into a low worm-risk lambing paddock, they have no signs of worms. A WormTest just conducted shows greater than 60% barber’s pole worm for an average count of 400 epg.
- Ewes early September, just shorn and will soon go into their lambing paddock 3 weeks before lambing starts. The paddock has not been prepared as low worm-risk.
- Ewes late August, just shorn and about to go into lambing paddock in 2 weeks for start of lambing. The paddock has been prepared as low worm risk.
- Lambs before weaning in a moderately good year, drenched at marking with a short-acting drench. The weaning paddock has not been prepared as low worm risk.
Links to the learning topics for Qld/NSW Summer Rainfall / Slopes and Plains
- Grazing management
- Breeding for worm resistance
- Worm testing
- Drenching (you are currently on this page)
- Drench resistance management
- Sheep worms