Temperature and Relative Humidity Inside Trailers During Finishing Pig Loading and Transport in Cold and Mild Weather

SIMPLE SUMMARY: The multi-site nature of the modern pork industry makes transport an essential part of swine production. It is well documented that transport induces stress in pigs. Bedding levels can have a significant effect on temperature and relative humidity inside the trailer. This study aims to determine the effects of bedding level on trailer temperature and humidity between average air temperatures of 4 °C and 18 °C. Relative humidity was greatest when higher levels of bedding were used during loading and transport in cold but not mild weather. ABSTRACT: The effect of bedding levels and trailer compartment on internal trailer temperature and relative humidity (RH) during loading and transport of finishing pigs was evaluated in cold and mild weather. Three levels of bedding were used in each experiment: 0.6 m(3), 1.2 m(3), and 2.4 m(3). In mild weather, internal temperatures were lower when 1.2 m(3) or 2.4 m(3) of bedding were used during loading and transport compared to 0.6 m(3) (P < 0.05). Internal trailer temperature increased in a quadratic fashion in the top front compartment when 1.2 m(3) was used (P < 0.05), and in a linear fashion in the top rear compartment when 2.4 m(3) were used in cold weather (P < 0.05). In mild weather, temperature increased linearly in the top front compartment with heavy bedding levels. Relative humidity increased in a linear fashion in the top front compartment with 0.6 m(3), bottom front with 1.2 m(3), and top front with 1.2 m(3) in cold weather (P < 0.05). In general, temperature and RH increased as bedding levels increased in both cold and mild temperatures. Excess bedding can absorb more moisture, resulting in transport loss and decreased animal welfare