In a muddle about worming drugs? Fear not as our expert vet Kirstie Pickles provides some helpful advice.
“When it comes to worming your horse, picking the right treatment depends on your ability to pick the right drug, not the right brand or wormer name,” says XL Equine vet Kirstie Pickles.
To make these clear Kirstie explains the three classes of worming drug along with a few nuggets of info to help differentiate them:
In horses this drug’s called fenbendazole and there’s now widespread resistance to it. In fact 75% of cyathostomins (e.g. that’s small red worms) are resistant to it. Resistance to this drug is worse in the south of the country where race yards and studs have over wormed on a large scale, for a long time. In rural Scotland, resistance is less of a problem.
TREATS: Encysted small redworm larvae, large and small redworm and large roundworm
Rolls right off the tongue this one doesn’t it? Thankfully the equine version of this drug is pyrantel and the good news is that in the UK, resistance to it isn’t too bad. In the US however, a bizarre move saw this drug introduced in a daily in-feed wormer leading to complete resistance. This would be like us taking a little penicillin every day to ensure we never got an infection – a surefire way to ensure resistance and a very bad move.
TREATS: Adult redworm, large roundworm and a double dose will treat tapeworm.
In horses these include ivermectin and moxidectin. These tackle encysted worms (a job that was once shared with fenbendazole but resistance to that drug means it’s no longer useful for this).
TREATS: Redworm and roundworm (Ivermectin), encysted redworm larvae and roundworm (Moxidectin).
This drug tackles active tapeworms in horses.
TREATS: Tapeworms only.