Horse Fly Strike and Insect Welfare Management

Flies and other biting insects cause significant welfare harms to horses, making effective insect management an important component of equine care during warmer months.

Key Facts

Horses can be bitten hundreds of times daily by insects in unmanaged environments
Face flies feed on horse eye and nasal secretions causing irritation and potential disease transmission
Bot flies lay eggs on horse legs which are ingested during grooming causing intestinal parasitism
Stable flies bite legs causing horses to stamp and kick in pain
Fly bonnets, masks, rugs, and repellents reduce insect impact when used correctly
Insect vector management reduces risk of equine infectious anemia and other vector-borne diseases

Welfare Considerations

Horses plagued by insects experience constant irritation and pain from biting flies that prevents them from resting comfortably and causes behavioral changes including stamping, tail swishing, head shaking, and seeking shade. The cumulative stress of heavy insect pressure over an entire summer season significantly impacts horse welfare. Eye infections from face fly irritation and intestinal damage from bot larvae represent health impacts beyond the immediate discomfort. Effective fly management is a welfare responsibility that many horse owners underestimate.

What You Can Do

Provide fly protection including masks, bonnets, and leg wraps during high insect season
Use appropriate insect repellents and reapply as directed for continued protection
Implement environmental management including manure removal to reduce fly breeding sites
Treat horses for bot fly larvae with ivermectin in autumn after first frost
Provide shelter or shade where horses can escape from heavy insect pressure