Modelling in support of decision-making for South African extensive beef farmers

In this study it is shown that it is possible to build a decision support system for the use of South African extensive beef farmers. Initially models for the key variables which affect extensive beef farmers are developed. These key variables include rainfall, beef, veal and weaner prices and the condition of the veld. This last key variable is monitored using the voluntary lick intake of the cattle and is modelled in terms of rainfall and stocking intensity. Particular attention is paid to the interrelationships between the key variables and to the distribution of modelling errors. The next stage of the study concerns the use of these models as a decision-support tool for extensive beef farmers. It is shown that Monte Carlo simulations and dynamic programming analyses can use these models to suggest how gross margins can be increased. At the same time these methods can be used to monitor the effect of management decisions on mean lick intake and, hence, the effect of these decisions on the condition of the veld. In particular the decisions of "what stocking intensity", "what cattle system", "when to sell" and "when to make a change" are addressed.