The purpose of this paper is to provide an insight into the methodology used in calculating coefficients for the livestock sector of the Center for Agricultural and Rural Development's (CARD) linear programming models. The livestock sector consists of four basic livestock activities—feeder cattle producing, feeder cattle finishing, dairy producing, and pork producing. These activities produce agricultural livestock commodities and nitrogen waste while requiring feed, water, energy, and capital. Four basic sources are used for the construction of the livestock sector—The Federal Enterprise Data System (FEDS), Nutrient Requirements for Beef Cattle, Dairy, and Swine published by the National Research Council, Utilizing Animal Waste as a Source of Nitrogen and Agricultural Resource Assessment System Technical Committee unpublished working papers.