Published online by Cambridge University Press: 28 April 2015
Dynamic, recursive simulation models for the national livestock-feed sector have been designed by agricultural economists for the specific purpose of making long-run projections and evaluating alternative agriculture policies (Reynolds et al.; Yanagida and Conway). While these models are useful for describing the workings of the national grain and livestock sectors, they are incomplete for policy evaluation purposes at a subnational or state level (Knapp et al.; Maki et al.). In these situations, unless state or regional production and marketing patterns are represented as a constant percentage of the national model solution values, the impact of changes in a state's crop or livestock production relative to other states and alternative policy decisions cannot be considered (Ratajczak). Consequently, a state model must be able to reflect the impact of national and international policies and events to be effective and functional (Colyer and Irwin).