Anthelmintic resistance in equine parasites is a growing welfare threat, and targeted selective treatment programmes are essential to maintain effective parasite control.
Equine parasitic disease causes significant welfare harm: larval cyathostominosis in spring causes acute diarrhoea, protein loss, and sometimes death as encysted larvae emerge simultaneously from the gut wall. Colic from migrating Strongylus vulgaris larvae causes severe abdominal pain requiring emergency veterinary intervention. As anthelmintic resistance limits effective treatment options, horses face escalating risks of inadequately controlled parasitic disease. Targeted selective treatment programmes that treat individual horses based on faecal egg counts rather than treating all horses routinely reduce drug use, slow resistance development, and maintain effective treatment options for genuinely high-shedding horses at welfare risk. Regular monitoring through faecal egg counts is an essential welfare practice.