The usefulness and efficacy of linear programming models as farm management tools

This study evaluated the usefulness and efficacy of linear programming (LP) models, and the Grazing Systems Ltd (GSL) model in particular. The GSL model was selected because it is the only LP model available for use in the farm business environment in New Zealand. Two approaches were used to evaluate the usefulness and efficacy of LP models and the GSL model as farm management tools. •The first approach involved case studies with two farm consultants experienced in the use of farm management models who worked with dairy farmer clients using the GSL model. The case studies resulted in an evaluation of both LP and the GSL model. •The second approach was an expert evaluation of the GSL model conducted by members of a research panel with LP experience who evaluated the GSL model against a set of LP modelling criteria they developed. The study concluded that LP can provide information to assist with improving farming systems, but the LP model has to be carefully constructed and interpreted so that model users will have confidence in the answers it provides. Users who are familiar with the concepts of marginal analysis will find that LP can provide valuable information to help with improving farm systems. However, consultants and panel members made a number of suggestions that would help to improve the “commerciality” of the model, such as an improved manual and formal training, better input and output functionality and better model availability. Potential users expect to be able to easily find information on the model from a range of sources, yet little information is available. If the GSL model is to be more widely used and accepted as another tool in the farm management kitbag, it would be helpful to improve its accessibility, data input and in particular, data output.DairyNZ, Ministry for Primary Industrie