One in three British horse owners are worming incorrectly, the results of a major survey suggest.
The findings from the latest National Equine Health Survey show some confusion over the correct worming product to use to treat encysted small redworms, indicating that some owners may be putting their horses at risk.
It is recommended that all horses in Britain should be wormed for encysted small redworms during November/December, even if they have a negative faecal worm egg count.
Nonetheless, this year’s survey showed that 29 percent of people who thought they had treated for this parasite had used products not indicated to treat for them.
Small redworms are the most common worms found in British horses and, in their encysted stage, are potentially fatal. The problem is that they do not show up in faecal worm egg counts and they may not cause any obvious symptoms. Owners often do not know their horse has got them.
There are only two active ingredients licensed to treat encysted small redworms: a single dose of moxidectin or a five-day course of fenbendazole. However, resistance to fenbendazole is now widespread in Britain, so a resistance test is recommended before using it.
The survey showed that 64 percent of those who specified how they treated for encysted small redworm had correctly used moxidectin either as solo therapy or in combination with praziquantel (compared with 71% in 2014).
Seven percent were found to have used fenbendazole, compared with 10 percent in 2014.
However, of the remainder, 22.5 percent had used ivermectin (18 percent in 2014), and 6.3 percent had used products licensed for tapeworm treatment.
The national equine veterinary manager for animal health company Zoetis in Britain, Wendy Talbot, said encysted small redworms were potentially the most harmful parasites to affect horses in Britain.
“Yet the survey results show consistent confusion over the correct product to use to minimise risk.
“It is imperative for owners to discuss their worm control plan with their vet or suitably qualified person and use the right product at the right time to safeguard their horses’ health.”
Tips for year-round worm control in adult horses in Britain:
- Strategic treatments for all horses: Encysted small redworm – November/December (can be combined with a treatment for bots).
- Targeted treatments: Every two-three months throughout the grazing season carry out faecal worm egg counts and then treat for strongyles as required.
- Once or twice a year: Administer a tapeworm treatment or consult your vet about testing.