Cattle Fly Control and Welfare in Pastoral Systems

Fly burden is a significant but underappreciated welfare problem in cattle, causing chronic irritation, reduced productivity, and disease transmission across pastoral systems worldwide.

Key Facts

Horn flies can each bite a cow up to 400 times per day, causing measurable blood loss
Fly-stressed cattle spend 20 to 30 percent less time grazing, reducing body condition
Face flies transmit pinkeye (infectious bovine keratoconjunctivitis), a painful eye infection
Stable flies cluster on legs and cause cattle to stamp, bunch, and lose weight
Insecticide resistance in fly populations is increasing due to over-reliance on chemical control
Physical barriers like sticky traps and walk-through traps can reduce chemical use
Proper manure management significantly reduces fly breeding habitat on farms

Welfare Considerations

Fly burden causes sustained, low-grade suffering that is easy to overlook because it is not dramatic. A heavily fly-burdened cow is in near-constant irritation — stamping, switching her tail, and unable to rest or graze normally. Over a summer season, this chronic stress reduces weight gain and milk production substantially. Eye infections transmitted by face flies cause intense pain, photophobia, and if untreated, permanent blindness. The welfare cost is compounded by the cumulative nature of fly stress across the grazing season. Integrated fly management that combines hygiene, biological control, and targeted pesticide use is more effective and reduces chemical impacts on beneficial insects.

What You Can Do

Support grazing operations that use integrated pest management for fly control
Advocate for research into biological control methods for agricultural fly species
Support farm welfare audits that include assessment of ectoparasite burden
Encourage producers to prioritize manure management to reduce fly breeding habitat
Ask beef and dairy supply chains about fly management protocols on farms they source from