A whole-farm model of a dairy farm was optimised to assist the strategic decision making given the uncertain environment. Decisions under consideration included the stocking rate, the calving pattern (defined by calving and dry-off dates) and the use of supplementary feed. These individual decisions are considered as the choice of a farm system in this paper. The farmer’s decision making problem is simplified by assuming a perfect labour market, and so the farmer will be primarily concerned with the return on equity. Farm systems are compared with stochastic dominance or the Sharpe ratio, depending on whether there is a perfect capital market and returns are normally distributed.