The word coming from New Zealand is that farmers are getting out of sheep due to anthelmintic resistance (AR).
This is what Tom Coll, a Teagasc advisor, told farmers at a farm walk in Co. Sligo at the beginning of the month.
“What we are hearing coming from New Zealand is that farmers had to get out of sheep due to AR,” he told attendees.
“That’s the reality of it when it comes to a stage that no products are working on farms,” he continued.
“After only three years of use in New Zealand, Zolvix [orange drench] had broken down – which shows you how quickly resistance can build up.
“The rest of the more common drenches used had broken after a longer period of time.”
Farm walk
The farm walk, held on the farm of Francis Gonley and family as part of the Teagasc Better Farm Sheep Programme, saw a lot of interest in AR among farmers.
Discussions were held around slowing the build-up of it on farms and the best way to deal with the issue once it arises, as once a product doesn’t work there’s no coming back from it.
At Teagasc Athenry, it was said at the farm walk, AR is at a stage where the three main wormer products on the market are not working.
On his farm, Francis’ strategy with worms is to treat lambs early in the season with a white drench to deal with Nematodirus.
Then, later in the season, a faecal egg count reduction test is carried out to determine what wormer is best to use on lambs based off the result of the test.
Once a wormer is given, a test is carried out again from a sample of lambs in the groups to see if the dose is working, typically seven days later after administered, which it is.
Resistance is determined when a dose doesn’t kill at least 95% of worms.