BEVA expands wormer-resistance guidance for horse owners and vets

The British Equine Veterinary Association (BEVA) has expanded its ProtectMEtoo toolkit with new guidance on monitoring and managing resistance to anthelmintics, the drugs used to control worms in horses. Developed by BEVA's Anthelmintic Working Group, the guidance sets out how vets and owners can use a Faecal Egg Count Reduction Test (FECRT) to check whether a wormer is still working effectively within a group of horses, and how to interpret the results.

Resistance to all three of the main anthelmintic drug classes has now been reported in UK horses, a problem driven in large part by routine, calendar-based worming of every animal regardless of need. BEVA's guidance encourages a shift towards diagnostic-led, targeted treatment instead, with faecal egg counts and FECRTs used to decide which horses actually need worming and to catch reduced drug efficacy early, before resistance becomes established and difficult to reverse.

For breeders and yard managers, the toolkit's advice goes beyond testing: it also covers pasture and stable hygiene, such as regular removal of droppings and appropriate grazing management, and stresses the importance of preserving "refugia" — a portion of the worm population left unexposed to treatment — to slow further resistance developing. The guidance is aimed at supporting sustainable, evidence-based parasite control that protects both individual horse welfare and the long-term usefulness of the anthelmintics still available.