Transport stress affects billions of farmed animals annually. Understanding the physiology of transport stress helps identify the most effective prevention and mitigation strategies.
Transport stress in farmed animals is a multifactorial welfare problem involving the combined effects of noise, motion, novel environments, unfamiliar conspecifics, temperature extremes, food and water deprivation, and handling by unfamiliar humans. The physiological stress response triggered by transport suppresses immune function for days, increasing disease risk during and after transport. Animals with transport stress have elevated cortisol, impaired thermoregulation, and altered muscle glycogen that affects meat quality. The most welfare-effective interventions address the highest-stress elements: mixing unfamiliar animals, loading and unloading, extreme temperatures, and excessively long journey durations. Short, well-managed journeys in good vehicles with trained handlers minimize the welfare cost of transport that is genuinely necessary.