Simulation models can be considered as learning tools, according to the idea of "flight simulator", where users would benefit by experimenting with possible realities, even more if they are built with the potential stakeholders in a participatory way. The IPA (Agricultural Planning Institute) developed a model to represent an extensive breeder cattle farm on a representative basaltic soil: the MEGanE (Model of an Extensive Stock Breeding Farm). The results of the simulation, both for forage production and zootechnics, show great consistency with national research information. Also, the MEGanE was able to reproduce a known drought crisis, with results consistent with a possible reality. The MEGanE has been designed to exchange concepts, with variables easily understood by potential users.