Dairy production causes unavoidable losses in respiration, feces, and urine, which may become an environmental burden as contributors to the “greenhouse” effect (CO2, CH4) or to the pollution of air NH3), soil, surface, and subsoil water NO3, P). Losses in respiration can be reduced by increasing feed quality and level of production. Increased feed quality can reduce losses in methane, whereas an increased level of production decreases the relative losses in maintenance. Fecal and Urinary losses can be reduced by minimizing the intake of N and P relative to energy. Further reductions can result from increasing feed quality and level of production, from matching or synchronizing the availability of N and energy in the rumen, and from shifting the site of digestion of protein and starch from the rumen to the small intestine. Improved feed quality will reduce endogenous protein losses. In order to exploit fully the potential of nutritional management in pollution control, computer simulation models describing dairy production in a dynamic way are needed.