Simulating rotational grazing management

Dairy systems predominantly based on rotational grazing are notoriously har d to manage. In order to ensure profitability, this type of production requ ires quite good organisation, planning, and operating capability on the par t of the farmer. A simulation-based decision support system, called SEPATOU , has been developed for this purpose. At the core of the decision support approach lies an explicit and rigorous modelling of the management strategy that underlies a dairy farmer's decision-making behaviour (real or hypothe tical). The SEPATOU system is a discrete-event simulator that reproduces th e day-to-day dynamics of the farmer's decision process and the response of the controlled biophysical system for which models of grass growth, animal consumption, and milk production are used. SEPATOU provides the means to ev aluate and compare tentative strategies by simulating their application thr oughout the production season under different hypothetical weather conditio ns. The relative worth of a strategy can be assessed by analysing the effec ts on the biophysical system and their variability across the representativ e range of possible conditions that is considered. The activities to be man aged concern the type and amount of conserved feed, where to fertilise and how much, the choice of fields to harvest, and most importantly, which fiel d to graze next. Typically, SEPATOU is designed to be used by extension ser vices and farming system scientists. It is implemented in C++ and is curren tly undergoing a validation process with the intended users. (C) 2001 Elsev ier Science Ltd. All lights reserved.