AANWENDING VAN SIMULASIES OM DIE EFFEK VAN REeNV AL ONVOORSPELBAARHEID IN DIE BEPLANNING VAN VEEBOERDERYPRAKTYKE UIT TE SKAKEL

This study evaluates a biological and financial method of planning developed in Australia and carried out with the aid of the RANGEPACK Herd-Econ program. It has been used in research to assist the cattle-farmer with strategic planning. The unfamiliarity of climatic variables/or planning purposes, made the study of historical rainfall from 1952 to 1991, imperative. On the grounds of Tyson's many years of research, a presupposition of 18 year cycles in the summer rainfall regions, were made. Rainfall until 2031 has been predicted for the Villiers District. Thirty rainfall simulations have been made and the data has been converted to kilograms natural pasture (dry material/DM) by the PUTU 11 simulation model, developed at the Glen Agricultural Development Institute. The pasture available for the specific period will determine the size of the herd. The current cash surplus after 36 years, normal distribution, is between R -1 500 000 and R 1 500 000. Three scenarios have been made on one below average simulation outcome. In the first scenario twenty 9110 month old calves were kept and the rest were sold. In the second scenario twenty 9/10-year-old calves were kept and the rest were sold and the older cows were sold during hard times and in the third scenario more than twenty heifers were kept until after the second calf. 5 year-old cows in calf were sold at a premium and during hard times /ewer of the old cows were sold. The result doubles the current cash surplus, emphasizes the advantage of the model, is time-saving, stimulates creative thinking and creates effective management.