ANÁLISIS Y SIMULACIÓN DE POLÍTICAS DE REEMPLAZO EN GRANJAS DE EXPLOTACIÓN PORCINA

This research project proposes a simulation model based on discrete-event simulation (DES) developed with ARENATM. This model represents the operation of a large sow farm. The main objective of this research is to identify a good-enough replacement policy that guarantees the best economic outcome of the farm under analysis over time. The main decision variable is the maximum number of cycles allowed for the sows? lifespan in the herd. Main income comes from the sales of piglets and less from culled sows, while the costs considered are those by feeding the animals, acquisition of gilts and operating costs incurred in the farm. The complexity of herd management, stochastic nature and interdependence between several factors in this system, make DES as an adequate methodology. The system was modeled through three stages according to physiological states of sows, and the sow?s migration between them is modeled through transition probabilities dependent on the reproductive cycle considered (i.e. number of parity). Input data was borrowed from literature and official statistics of Spanish sow farms. Output data was evaluated through of averaged daily profit. The result showed that considering eight reproductive cycles is the best alternative in the farm management.