The important sheep drench, Startect®, may be in short supply from late 2026 and Wormwise Programme Manager Ginny Dodunski is advising farmers to plan ahead and consider system changes to reduce their reliance on drenches.
Sheep farmers battling resistance to the older classes of drench are concerned that they may face another season like the post-covid one, where both Startect ® and fellow ‘novel’ drench Zolvix® were unavailable, and managing resistant worms in lambs in autumn and winter became problematic.
The background
Producer of Startect, global animal health company, Zoetis, has been advised by the manufacturer of the unique active ingredient, Derquantel, that it will no longer manufacture the drench active. Zoetis is now looking for a new manufacturer for the unique active ingredient in this product. Resultingly, Startect will most likely be unavailable in 2027, although New Zealand’s 2026 supply is secure and Zoetis advises it will actively manage supply to ensure customers are treated fairly.
What can B+LNZ and affected farmers do in the meantime?
There is little that a levy body like B+LNZ can do to influence the business decisions of a multinational such as Zoetis. I’m sure the Kiwi and Aussie Zoetis livestock teams are losing sleep at the moment trying to get some other means of manufacturing Startect into play.
In a best-case scenario, farmers may have to do 12 months without Startect, from sometime towards the end of this year. This has a similar feeling to the withdrawal of long-acting pre-lamb capsules from the New Zealand market in 2023, and our advice is also of a similar nature to what was given back then:
This advance warning gives plenty of planning time to set up fatter ewes that don’t need drenching and wean heavier lambs, as well as setting up lamb feed options that require less drench inputs.
This may sound trite to farmers still using a lot of drench, but equally we know there are others out there who have substantially reduced their drench inputs.
Not through ‘BAU but with less drench’, but through policy and strategy that sets up a system where lambs spend less of the year contaminating permanent pasture with resistant worms.
There’s a heap of new information in the updated Wormwise Handbook (PDF, 9.45MB).
However, this new resource is very clear that we can’t provide recipes for drench use. Having a thorough monitoring plan to understand what drenches are working and when, on individual farms is key. The new GIN PCR worm species test is already proving really helpful for rapid-turnaround testing for farmers to know which worm species are on board before they drench.
Farms that are relying completely on Startect® and Zolvix® to control resistant Trichostrongylus are going to come under pressure and will need to figure out how they can have as few lambs on permanent pasture through the time that these are a threat on their property.