The optimum profitable combination of venison, velveting stags and breeding hinds

Abstract

The objective of this study was to develop a simple and flexible linear programming model to optimise pastoral deer production systems. It is the author's aim to use the model as a tool for professional farm consultancy in order to improve the effectiveness of deer farm development and management decisions in any region of New Zealand.The model was implemented using the linear programming package Beeline, within the spreadsheet package Lotus 1-2-3. The objective of the model was to maximise gross profit through the optimum use of available resources subject to specified constraints. The model can also be used in association with objectives other than profit maximisation. For example, a farmer's objective may be to minimise the labour requirement while sustaining a certain level of farm income. A hypothetical farm (200 ha), based on Winchmore irrigated pasture growth rate data, was incorporated into the model to test the outcome. The major constraint encountered on designing the model was the size of the linear programming package within which it operated. For this reason the model was simplified to 240 constraints and 170 variables. Analyses of the results showed that the optimised solution was highly sensitive to changes in both prices and annual pasture growth rates. Changing the annual pasture growth rates highlighted both the possible change in profit and the change in optimum profitable combination of deer production systems on one farm as the pasture growth rate varies from year to year. A number of suggestions were proposed for improving the model before it would be suitable for farm management or consultancy use. It was concluded that a larger linear programming package was needed before these suggestions could be fully implemented.