A trial testing different drench resistance test methods is currently under way. Funded by AWI and conducted by Dawbuts, the free trial is now calling for woolgrowers to get involved.
Australian sheep producers spend an estimated A$93 million per year on sheep drenches. However most of the time, they don’t know if the drench is working. One of the reasons why farmers do not drench test is because the traditional test is based on low-sensitivity counts that require a mob average of 300 epg before it can begin. This may be hard to achieve, especially if the sheep are being managed for low worm burdens. The second problem is that leaving sheep until they have higher worm burdens exposes them to the risk of sickness and low production.
Veterinary parasitologist Dr. Janina McKay-Demeler of Dawbuts is comparing the performance of four different drench resistance test methods. She has set up the trial to clearly show the strengths and weaknesses of the various approaches to drench testing.
“We have trialled the Mini-FLOTAC for drench testing in sheep in Europe and the results are impressive, but it is a different story in Australia with big mob sizes, high levels of some worms such as barber’s pole worm and more advanced drench resistance,” Dr McKay-Demeler said.
“This trial covers all of Australia and by this time next year we will be able to analyse how each of the methods performs under real-world conditions. The objective is better worm control for Australian sheep producers and that can only improve both welfare and productivity.”
To achieve this, sheep producers across Australia are encouraged to collect dung samples from a mob of wormy sheep on the day of drenching, then again 14 days after the drench. The samples are sent to the lab and subjected to a four-way analysis:
* Traditional worm egg count - with an un-drenched control group for comparison.
* Traditional worm egg count, but the ‘before’ samples are used instead of an un-drenched control group.
* Mini-FLOTAC worm egg count (higher sensitivity) with an un-drenched control comparison group.
* Mini-FLOTAC, using the ‘before’ samples as control group.
For Monaro fine wool producer Nancy Spoljaric, knowing the resistance status of worms in her sheep has provided peace of mind.
“The Monaro is tending towards more dominant summer rainfall, which is facilitating the population growth of barber’s pole worm so we find that this worm is becoming an increasing problem in the area. Many of our farmers are seeing anaemia and poor performance in weaners and ewes over the late summer especially when effective worm control has not been achieved in the spring,” explained Nancy.
“When sheep are treated for barber’s pole worm we need a high efficacy (>95% worm kill) otherwise the prolific egg laying capacity of this worm results in long term pasture contamination, especially because hatched larvae can survive on the paddock for many months. Knowing the efficacy of the combination drenches means we can select and use drenches with increased confidence that they will do the job.”
Nancy was one of 15 farmers in the Monaro that participated in AWI’s research project to trial different methods of drench resistance testing. The aim is to derive a new method based on recently-developed technologies for counting and analysis. The result should be a drench resistance test that is simple and cheap to conduct but provides diagnostic answers that are robust and reliable.