Nutrient emissions from animal feeding operations continue to degrade water and air quality. New regulations will limit the amounts of nutrients that can be locally applied to land. In this article, a structural-dynamic model of a livestock-crop operation is calibrated with data from a representative farm and is used to predict the effects of nitrogen regulations. Policy simulations clarify the importance of dynamic elements and demonstrate three main results: (1) cost estimates are relatively high; (2) cross-media pollution effects are potentially large; and (3) improved input management appears most promising for reducing both emissions and waste management costs. Implications for policy and future research are discussed.