Fly Control and Cattle Welfare
Flies cause significant welfare problems in cattle through direct harassment, disease transmission, and production losses. The welfare impact of fly burden is often underestimated — cattle under severe fly pressure show continuous distress behaviour, reduced grazing time, and measurable production losses. Effective fly control is a genuine welfare intervention.
Welfare Impact of Fly Infestation
The main fly species affecting cattle in Britain include face flies (Musca autumnalis), stable flies (Stomoxys calcitrans), horn flies, and warble flies (now largely eradicated from Britain). Face flies cluster around the eyes and muzzle, causing eye irritation, tear-staining, and transmitting New Forest Eye (Infectious Bovine Keratoconjunctivitis). Stable flies bite the legs and abdomen, causing painful bites and blood loss.
Under high fly pressure, cattle spend substantial time in avoidance behaviour — bunching, head-tossing, stamping, tail-switching, and seeking shade or wind. This behavioural disruption reduces grazing time by 30-40% in heavily infested animals, directly impairing nutrition. The cumulative welfare cost of daily fly harassment throughout summer is substantial.
Control Strategies
Pour-on insecticides: Synthetic pyrethroids applied along the backline provide systemic and contact fly control for 4-8 weeks. Effective for both face flies and stable flies. Resistance developing in some stable fly populations requires rotation of active ingredients.
Ear tags: Pyrethroid-impregnated ear tags provide long-season fly control through slow release. Most effective when applied at turnout; removed at housing to reduce resistance development.
Fly traps and sticky traps: Useful for monitoring fly populations and reducing stable fly pressure in and around buildings. Environmental management — removing manure rapidly, ensuring proper silage and slurry storage — reduces breeding sites.
Natural control: Dung beetles parasitize fly larvae in cattle manure — avoiding systemic insecticides where possible preserves dung beetle populations that provide natural fly control.
Housing and Shade
Providing shade structures or sheltered areas gives cattle relief from fly pressure during peak fly activity. Flies are less active in shade and moving air — fans in housed areas reduce stable fly activity. Summer housing (keeping cattle in during peak fly hours of warm afternoons) reduces cumulative fly exposure at the cost of other welfare considerations around behaviour restriction.