Whole farm planning for a large scale sheep and beef cattle farm : a case study : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Farm Management at Massey University, New Zealand
The use of pasture by grazing animals is the basis of New Zealand pastoral agriculture. Therefore, a major part of the management of pastoral-based farms concerns decisions about the allocation of feed to livestock. The aims of this study were first, to develop a linear programming (LP) model for the case study farm. Secondly, to use this model to determine optimal farm plans and associated information. Thirdly, to evaluate the technique as to its suitability as an aid to farm planning. The LP model developed in this study was built to investigate alternative means of increasing farm profitability for Limestone Downs, a large sheep and beef cattle property situated on Raglan County. The model allows pasture to be used by grazing animals in 12 periods throughout the year, subject to maximum and minimum constraints on pasture cover which have the effect of limiting the amount of feed that can be transferred from one period to the next. Supplementary feed activities within the model include hay and nitrogen. The animal production activities considered by the model were: (1) a breeding sheep system producing meat and wool; (2) a beef cattle system comprising breeding and finishing stock; and (3) a bull beef system. The model was used to optimise farm surplus ($/farm). The results demonstrated that farm profitability could be substancially increased in direct proportion to the rate at which bull beef substitutes for, firstly sheep, and secondly breeding and finishing cattle. However, to attain higher profits, current management constraints, in particular the maximum number of Friesian bulls and/or the minimum number of breeding ewes on the property will have to be overcome. Investigation of these issues as well as the effect of climatic variability on the various plans derived are clearly identified as areas requiring further study and consideration.