MODELING FEED-INTAKE IN GROUP-PENNED GROWING-FINISHING SWINE

A model of feed intake in group-penned swine was evaluated for six gro ups of four pigs each housed in three constant environmental condition s-one thermoneutral and two under different degrees of heat stress des igned to reduce voluntary feed intake by 13% and 26%. The model used a five state Markov chain to simulate meal initiation and duration amon g a pen of animals. Feed intake rate was assumed to be a realization o f a normally distributed random variable. The product of meal length a nd rate was used to simulate feed intake. Results of simulations were compared to measured results for the pigs during daylight hours over a three-week period when the animals were approximately 40 kg live weig ht. Simulated meal duration was found to correspond reasonably to meas ured data, but tended to overpredict the occurrence of shorter meals. Intake rate was found to be non-Gaussian, but did not influence the si mulation results to any great extent and this model was concluded to b e satisfactory. Simulation results for meal size were similar to those found in meal duration. Overall, the models provided an efficient mea ns to simulate feed intake in group-penned swine.