Fly harassment causes significant welfare harm to cattle during summer months, with fly control programs reducing both welfare impacts and productivity losses from fly-related stress.
Fly harassment causes sustained discomfort and behavioral disruption for cattle during summer months. Cattle under heavy fly pressure spend significant time and energy engaged in fly-avoidance behaviors - bunching, head shaking, tail switching, and seeking shade - at the expense of normal grazing, rumination, and social behavior. Horn flies in large numbers cause measurable blood loss and continuous irritation. Face fly damage to the eye predisposes to painful IBK infections. The welfare case for fly control programs is strong, and the management benefits of reduced fly pressure - improved grazing behavior and feed intake - align with welfare improvement.