"The need for animal production decision-making tools is essential to ensuring sustainable animal protein production. Of the decision-making tools available, there is a lack of consideration for year-after-year consequences of and the interaction between animal production, manure storage, manure land application, and crop nutrient uptake. A model was created to address this gap using a grow-finish swine system with respect to nitrogen and phosphorus losses. Empirical formulas and published information of nutrient retention or losses were used in the development of a management decision driven model. Observed results from a previous study at Michigan State University were compared to calculated results to assess the validity of model outputs. Calculated outputs for total manure excretion, nitrogen excretion, and nitrogen loss from the system were within the error found in the observed data. The model was tested further by modifying the baseline scenario to test model sensitivity. Changes in manure storage and dietary phosphorus concentrations had a greater impact on management longevity than manure application method and field location. The results of the model assessment indicate high variability in outputs, but this may reflect high variability in animal production observation, indicating that model outputs still portray a realistic vision of a grow-finish swine facility. This model allows the identification of critical control points within the system to help direct future research and support producers and advisors in creating a long-term, sustainable animal protein production system."--Page ii.
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