Current methods of formulating animal rations lead to excess nutrient excretion which can potentially lead to excess manure nutrients and an increase in economic costs. These methods do not recognize the impact of diminishing returns. The objective is to simultaneously optimize feed ration composition and replacement. The results, when compared against results from a survey of feed companies, indicate that using a profit maximization rather than live weight growth maximization criterion targets nutrients to an animal's actual needs and, hence, fewer nutrients are excreted and higher returns for producers are obtained.
