Livestock transport in hot weather causes acute heat stress that can be fatal; journey time restrictions, ventilation requirements, and temperature monitoring are critical welfare safeguards.
Heat stress during livestock transport is one of the most acute welfare emergencies in the food system. Pigs crowded in stationary vehicles in traffic in summer temperatures can reach fatal core body temperatures within minutes. The physiological stress of transport — movement, noise, unfamiliar social groups, inability to access feed and water — is compounded by thermal stress into a welfare emergency. The regulatory framework around transport temperature limits and journey time restrictions exists precisely because of this risk, but enforcement is patchy and deaths on arrival remain a significant welfare problem during summer months.