Measurements of Thermal Microenvironment in a Swine Transport Trailer

Transportation has been recognized as an important aspect that affects meat quality and profit in pork production. The objective of this study was to measure the microenvironment surrounding the animals in the transport trailer through seasonal testing. Fourteen tests were performed over three seasons (hot, mild and cold) to determine seasonal trends in the microenvironment of the animals during transport, with exposure to temperature extremes. A total of 156 market-weight pigs were loaded onto a straight, dual-deck semi-trailer for each trip. Results showed that the average compartment temperatures were often higher than external temperature before traveling, but generally cooled down to be consistent with external temperature during transport, because of relative air velocity. Average compartment air velocity was highly correlated to truck travel speed. Skin surface temperatures of pigs were highest while waiting at the farm after loading and decreased during transport. Carbon dioxide levels were higher in compartments towards the front of the trailer, indicating that ventilating air entered the rear of the trailer and exited out the front. The data collected in this study is important to evaluate the animal microenvironment during transport. These data can also be used to help develop a simulation model to improve trailer designs, reduce animal stress level and reduce economic loss from transport losses and optimize the practice of animal loading and transporting.