Fly Control and Cattle Welfare in Summer Grazing Systems

Biting and nuisance flies cause significant welfare impacts in grazing cattle throughout summer, impairing feeding behaviour, causing skin irritation, and spreading diseases including pinkeye and summer mastitis.

Key Facts

Horn flies can exceed 200-400 per animal, each feeding up to 40 times per day
Cattle irritated by flies spend significantly more time bunching, standing in water, and tail-switching
Face flies are primary vectors for the bacteria causing infectious bovine keratoconjunctivitis
Summer mastitis in dry cows is associated with head fly feeding on teat ends
Effective fly control can improve feed conversion efficiency and reduce disease burden

Welfare Considerations

Fly burden causes chronic welfare harm in cattle throughout the grazing season. High-density fly infestations prevent normal grazing behaviour, reduce time spent resting, and cause skin damage from biting flies. The subsequent welfare cascade from disease transmission, including painful eye infections and mastitis, amplifies suffering. Integrated fly control strategies combining pour-on insecticides, fly traps, ear tags, and good manure management offer substantial welfare and productivity benefits.

What You Can Do

Implement integrated fly management programmes combining multiple control strategies
Provide shade and access to water to allow cattle to seek relief from fly pressure
Monitor cattle regularly during summer for signs of fly-associated disease
Work with your vet and agronomist to design a fly control plan appropriate to your system