The use of iterative linear programming in practical applications of animal diet formulation

This paper considers two nonlinear optimisation problems arising in animal feed formulation, and shows how they can be formulated as an iterative sequence of linear programming problems. The first is concerned with the problem of meeting the nutrient requirements of the dairy cow in the case when nutrient requirements are taken to be a function of the diet fed. The second problem is concerned with formulating batches of animal feed when raw material nutrient content is variable, and it is necessary to meet nutrient requirements with a given probability. It is shown how these problems can be solved using the Ultramix feed formulation and modelling system. Ultramix is species independent system consisting of several integrated modules which include a modeller and an optimiser. Iteration is achieved by linking nutrient specifications to values obtained from the modeller, and by defining suitable stopping rules.