Modeling skin temperature to assess the effect of air velocity to mitigate heat stress among growing pigs

Abstract. It is generally accepted that increased air velocity can help to mitigate heat stress in livestock housing, however, it is not fully clear how much it helps and significant uncertainties exists when the air temperature approaches the animal body temperature. This study aims to develop a skin temperature model to generated data for determining the potential effect of air velocity to mitigate heat stress among growing pigs housed in warm environment. The model calculates the skin temperature as function of body temperature, air temperature and the resistances for heat transfer from the body to the skin and from the skin to the surroundings. The latter is modelled as the united resistance for convection, radiation and evaporation. The model considers that the thermal heat load affects the tissue resistance, the body temperature and the evaporation from the skin, which is managed by modeling the tissue resistance, the body temperature and evaporation from the skin as functions of the skin temperature. The results indicate that the combination of an air temperature of 24 °C and an air velocity 0.2 m/s results in the same skin temperature as the combinations of 27 °C and 0.6 m/s, and of 30 °C and 1.9 m/s.