Fly irritation is a significant and often underestimated welfare problem for horses in summer, causing persistent stress, wound risk from excessive tail-swishing and leg-stomping, and behavioral agitation.
Fly irritation represents one of the most overlooked welfare problems in horse management. The continuous low-level irritation of flies — biting, crawling, clustering around eyes and wounds — creates chronic behavioral stress that accumulates over months of summer exposure. Horses that cannot escape flies through shelter access or removal spend enormous energy in avoidance behavior. Sweet itch in susceptible horses causes suffering intense enough to drive horses through fences to escape biting midges. Fly protection through rugs, masks, stabling during peak biting times, and manure management directly reduces welfare costs that owners may not have quantified as significant.