Many livestock sector models have limited coverage of relevant variables and are somewhat ad hoc in their structure in the choice of what should be specified as behavioral equations. This study develops a generic conceptual approach to modeling the livestock sector that provides consistent rules of specification and better coverage of variables. The new approach departs significantly from existing models. This approach is applied to modeling the swine-pork sector of Japan and then used to analyze the impact of removing Japan's gate price policy and variable levy for pork imports.