Modelling the Relationships Between Farmers' Objectives and the Decisions Related to the Stocking Rate in Beef Production Systems of Central Brazil

In Central Brazil, the sustainability of beef cattle systems is under threat. More than half the 50 million ha of sown pastures are suffering from degradation. Overgrazing is one of the main causes, and therefore choice of the stocking rate is a crucial decision taken by the farmers. Hypotheses to explain the overgrazing paradox have been explored by a model where 'cattle ownership' and ‘economic returns' were optimized individually and then simultaneously, using Multi-period Linear Programming and Compromise Programming techniques. Different scenarios based on farmers' attitudes towards overgrazing, pasture costs and capital availability were analysed. In some cases, benefits from holding more cattle can compensate for the increasing costs of maintaining pastures - an observation that undermines the hypothesis that farmers practise overgrazing because they are unaware or uncaring about overgrazing costs. An appropriate approach to the problem of pasture degradation requires information on the economy of a wide range of pasture recovery and maintenance methods, accepting that some level of overgrazing could be rational.