Fly Control in Livestock: Welfare & Management

Flies and Livestock Welfare

Fly nuisance is one of the most significant but often underappreciated welfare challenges in livestock farming. Multiple fly species cause direct harm through biting, blood-sucking, wound colonisation, and disease transmission, as well as indirect harm through stress, reduced grazing, and energy expenditure in fly avoidance.

Key Fly Species and Their Welfare Impacts

• Stable fly (Stomoxys calcitrans): Blood-sucking fly causing significant pain at bite sites; cattle lose significant body weight when heavily attacked.
• Horn fly (Haematobia irritans): Persistent blood-sucker causing cattle to bunch, reduce grazing time, and lose condition.
• Face fly (Musca autumnalis): Feeds on secretions around eyes; causes eye inflammation and transmits Moraxella bovis (pinkeye).
• Blowfly (Lucilia sericata): Causes sheep strike — maggot infestation of live sheep causing severe pain, tissue destruction, and death if untreated.
• Warble fly (Hypoderma spp.): Eradicated from the UK but a serious welfare concern elsewhere; larvae migrate through cattle causing pain.

Behavioural Signs of Fly Distress

• Bunching, stamping, tail-switching, and head-shaking
• Reduced grazing and feed intake
• Seeking shade or water to escape flies
• Self-trauma from rubbing against surfaces

Integrated Fly Management

• Insecticides: Pour-on, spray, and ear tag formulations; rotation of actives to delay resistance.
• Biological control: Parasitic wasps (Spalangia spp.) that attack fly pupae in manure.
• Environmental management: Rapid manure removal, proper slurry storage, and clean bedding to disrupt fly breeding.
• Physical barriers: Fly screens, shelter design, and timing of turnout to avoid peak fly activity.
• Blowfly prevention: Preventive treatment before the fly season, daggying (crutching) sheep, and post-shearing treatment.

Key Takeaways

Fly control is a core component of livestock welfare management. Integrated approaches combining insecticide use, environmental management, and biological control provide the most effective and sustainable welfare protection against fly-related suffering.