Horn flies are a major welfare and production challenge for cattle in North America. Integrated pest management balances effective control with resistance prevention.
Horn fly infestations cause significant chronic welfare harm through constant painful feeding bites, behavioral disruption preventing normal grazing and rest, and the physiological stress of hosting thousands of blood-feeding parasites. The welfare harm extends beyond the individual - heavily parasitized cattle show elevated cortisol, reduced time lying and ruminating, and weight loss that affects long-term condition. Resistance management is a welfare concern because overuse of insecticides drives resistance that ultimately leaves cattle unprotected. The integrated approach that rotates insecticide classes, uses biological controls, and monitors resistance patterns protects both welfare and long-term control effectiveness.