Performance Evaluation of Fan-Ventilated Swine Trailer with Air Filtration for Maintaining Satisfactory Transport Conditions.

In response to new and emerging challenges in animal transport, including more stringent biosecurity and public demand for enhanced animal welfare, an innovative prototype trailer with mechanical ventilation and air filtration systems was developed. The performance of the trailer in maintaining acceptable environmental conditions for the pigs during transport in both cold and warm weather was evaluated through a series of road tests. In these tests, the general welfare of the animals during transport was also assessed. Results showed that temperatures inside the animal compartment during cold ambient conditions were above 10 °C for more than 60 to 90% of the trip despite the frequent occurrence of cold temperatures (below 0 °C) at the inlet. On the other hand, the temperature in the animal compartment ranged from 16 to 19.4 °C most of the time during transport in warm weather. The average moisture levels in the animal compartment ranged from 4.15 to 6.3 g/kg dry air and 5.05 to 78.8 g/kg dry air during cold and warm transport conditions, respectively, which is comparable to the humidity ratios measured in conventional pig transport trailers. Carbon dioxide concentration inside the animal compartment ranged from 912 to 1192 ppm in cold conditions and from 1008 to 1414 ppm in warm weather, indicating good air quality in the trailer during transport. Furthermore, there was no significant change in the levels of blood cortisol and in the rectal and body temperatures of pigs measured at the start and end of each monitoring trip, indicating that the pigs showed reduced or minimal stress during transport. The study demonstrated that the trailer design with a mechanical ventilation system significantly improved the thermal comfort and environmental conditions for pigs, contributing to their welfare during transport.