This was the view of experts at the 30th National Equine Forum on 3 March, who discussed the “collective responsibility” to tackle the issue. There is evidence of resistance to all four classes of worming drug available for use on horses, and no new types or drugs expected in the near future.
“This is a significant threat to our industry and uncontrolled, will lead to critical health and welfare issues,” said Claire Stratford, head of the efficacy team and anthelmintic policy lead at the Veterinary Medicines Directorate (VMD). “Responsible use of [these drugs] is essential to maintain them.”
Dr Stratford said the issue is a global one, and horses can transmit resistant parasites “between yards, countries and continents”. Although there has been no recent research in this country, it is thought that “most horses in the UK have probably got resistant parasites”.
“It’s not a cause for panic but it is a real threat to all our horses, and it needs urgent collective attention,” she said.
Dr Stratford’s VMD colleague Alison Pyatt said resistance is also a global issue in livestock, and that in the UK, a “pan-industry” approach had been very successful. With that in mind, the VMD convened a group of experts from across the equine sector.
Dr Pyatt said one positive was reports that awareness, and use of diagnostics such as faecal worm egg counts, had increased over the past 10 years, and pasture management had improved.
“But we found we’ve got a critical problem still,” she said. “That tells us we’re not doing enough.”
Dr Pyatt said a major problem is the fragmented sector. There is a challenge in the many different ways horses are kept, and a need for standardisation in egg counts. Communication is a key issue, as is engaging those owners who are still routinely worming.
British Equine Veterinary Association president elect David Rendle, a specialist in equine internal medicine, said it was encouraging to hear of this progress.
“But I fear the wider industry isn’t quite on the same page and doesn’t appreciate the urgency of the situation,” he said. “We know traditional worming strategies mean 80% of doses are completely unnecessary, and multiple surveys show that although use of diagnostics is improving, as few as 10% of people are using them appropriately.”
Mr Rendle said in the past year in the UK, 1.13m doses of wormer were given, and 120,000 faecal egg counts carried out, so about 11 doses for each count, which is “definitely the wrong way round”.
But he said recent research indicated that education on the subject does not work, as the desired behaviour, a diagnostic testing-based plan and only worming when necessary, is seen as more expensive and more complicated, with no perceived benefit to the owner.
He believes a change in rules is needed, so owners can only buy wormers as part of a proved annual plan based on testing, and only if a horse is shown to need them.
“The writing is on the wall for more death and disease, and pastures that can’t be grazed by horses,” he said. “That will have a radical effect on our industry, and it will be in years, not decades.
“We have to shape up how we sell these products; we have to change.”
Claire Shand, managing director of Westgate Labs, which carries out parasite diagnostics, said using faecal counts can reduce wormer use by about 80%.
“There’s absolutely no place any more for routine worming,” she said. “The humble egg count is the cornerstone of testing; they’re cheap, simple and we try to make them as easy for owners to use as we can. And we use them to maintain the efficacy of the womers we do need to give.”
Ms Shand added that appropriate dosing is also key, for horses who do need to be wormed, as not giving enough for a horse’s weight also contributes to resistance.
“All horses need good parasite control, and it’s future generations we need to do this for, and so we can keep grazing horses on our fields into the future,” she said. “My question is: what will you do when the wormers stop working?”
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