This paper argues in favour of a simulation approach relying on an explicit and rigorous modelling of the management strategy that underlies the farmer's decision-making behaviour. A strategy is defined as a roadmap of intended technical tasks over a management period. It is tied to an overall objective and specifies what to do depending on the situations encountered. An essential feature is its flexibility, enabling it to cope with stochastic fluctuations of the environment. In order to evaluate the worth of a strategy, the advocated approach relies on a simulation tool with which the effects of applying the strategy are evaluated under different hypothetical weather conditions. The example of a rotational grazing dairy production system is used to illustrate the modelling and simulation of a management strategy covering a production season. SEPATOU, the simulator built for this application domain, is designed to be used by extension services and farming system scientists. It provides a framework for virtual experimentation that can help to enhance decision-making capabilities of primary producers and find new or more profitable management strategies.