How inadequate ventilation and extreme temperatures in livestock trailers cause heat stress, and the management practices and design standards that protect animal welfare during transport.
Heat stress during livestock transport causes suffering that ranges from discomfort through physiological compromise to death. Pigs are particularly vulnerable — unable to sweat, highly susceptible to hyperthermia, and transported in vehicles that can trap heat rapidly in warm conditions. Transport mortality from heat stress is preventable through appropriate vehicle design, journey scheduling during cooler periods, and active cooling systems. Regulatory requirements exist in the EU but are not consistently enforced. The welfare improvement available through better vehicle design and scheduling is substantial and demonstrably achievable without prohibitive cost.