18. Diet Problems

This study concerns feed composition and planning and is mainly focused in reducing feeding costs. We also estimate the excretion of nutrients that can be harmful to the environment when applied in excess but without trying to reduce them. The diets are formulated to satisfy or exceed the animal’s requirements, so their growth will not be affected. Under these conditions, we can apply linear programming models. The resulting models are variations on the classical linear programming models. We study three types of feeding: traditional feeding, fixed energy density feeding with phases, and variable energy density feeding with phases. We will develop models corresponding to each feeding type. In a first time, the models established are linear mathematical problem. Introducing premixes for practical reasons, the models using variable or unknown premixes become bilinear. We will apply the developed models more specifically in the pigs growing context. This study shows that the feeding costs can be substantially reduced using variable energy density model with daily phases and variable premixes.