www.ars.usda.gov/northeast-area...m-system-model/
With tighter profit margins and increasing environmental constraints, strategic planning of farm production systems is becoming both more important and more difficult. This is especially true for dairy and beef production. Livestock production is complex with a number of interacting processes that include crop and pasture production, crop harvest, feed storage, grazing, feeding, and manure handling. Computer simulation provides a useful procedure for integrating these processes to predict the long-term performance, environmental impact, and economics of production systems.