Establishing Trailer Ventilation (Boarding) Requirements for Finishing Pigs during Transport

SIMPLE SUMMARY: Transport is an inevitable process in the modern swine industry due to the multiple-site approach to raising pigs and transport can be a significant source of stress to the animals, which raises a welfare concern. Maintaining the environment inside the transport trailer is crucial for pig comfort. This study aims to determine the amount of ventilation, or varied side-wall boarding, required to keep pigs within their thermal comfort zone. Examination of 302 trailers transporting 48,143 pigs found that pig losses were highest when low boarding levels (open sides) were used in cold air temperatures (<5 °C). In mild air temperatures (5 to 26 °C), boarding levels had little impact on pig losses. ABSTRACT: Specifically, this study aimed to establish the effects on mortality and morbidity of boarding levels (amount of side-wall trailer ventilation) for finishing pigs in mild weather (8.80 ± 0.30 °C, 71.70% ± 1.12% humidity). Pigs from commercial finishing sites were transported in 302 pot-bellied trailers to commercial processing plants. Measures collected at the processing plant were rates of dead on arrival (DOA), non-ambulatory, non-injured (NANI), non-ambulatory, injured (NAI), and total dead and down (D&D). Boarding levels (% that side walls were closed off with inserted boards) were divided into 3 bins: low, medium, and high, and outside temperature was divided into 4 bins <5 °C, 5.10–10 °C, and 10.10–15 °C and >15 °C. Average rates of DOA, NANI, NAI, and D&D were approximately 0.30%, 0.12%, 0.04%, and 0.46%, respectively. The D&D was highest when boarding level was low with temperatures <5 °C (p < 0.05). However, variations in boarding level (medium and high boarding) in the temperature range of 5.10 °C to 23.30 °C did not affect pig losses.