Modeling the Physiological Growth of Swine Part III: Heat Production and Interaction With Environment

Part 3 of this series presents the development and validation of the relationships used in the NCPIG computer model to simulate heat production and interaction with the thermal environment of growing swine. The model was developed to simulate transient, diurnal energy flows for growing pigs considering metabolic heat production, sensible and radiant heat gains and losses, latent heat losses and heat storage within the animal body. The relationships used in the model are described and the results of comparisons between predicted heat production and observed data for individually housed pigs are presented. The predicted and observed data were for crossbred gilts ranging in weight from 30-100 kg and for three levels of environmental temperature: lower critical temperature (LCT), LCT+58 C, and LCT-58 C. The simulated heat production values for the LCT experiment were within the observed mean minus one standard deviation while those for the LCT+5 and LCT-5 treatments were approximately one standard deviation above and below their respective means.