In the study farm, the entry and exit of animals into a paddock are determined by visual asessments of forage abundance. Animals are let into the paddock when forage abundance is high, and removed when it is low. These levels are arrived at by trial and error. The upper level is fixed in order to avoid pasture over maturity (which affects palatability), and to cope with the overall demand for forage in the farm. The lower level is fixed based on the growth response of the pasture after a grazing period: if the 'recovery time' is too long, the lower level must be increased.