Inadequate ventilation in livestock trailers during transport causes heat stress, respiratory disease, and death. Understanding ventilation requirements by species and season is critical for transport welfare.
Transport ventilation welfare failures cause acute suffering and death on a scale that is largely invisible to the public and under-regulated compared to other aspects of livestock transport. Heat stress in poorly ventilated trailers causes progressive suffering — distress, hyperthermia, respiratory failure — before death. Animals that survive severely heat-stressed journeys often arrive with compromised immunity, reduced productivity, and lasting welfare deficits. The technology to prevent most transport heat mortality exists and is affordable; the barrier is regulatory standards that do not mandate minimum ventilation performance, and an industry culture that accepts avoidable heat deaths as transport losses. Welfare-motivated transport policy must address ventilation specification alongside journey time and rest period requirements.