Initial Evaluation of a Model to Optimized Digestible Lysine Levels When Ractopamine is Fed

Purdue University 2001 Swine Research Report. Ractopamine is a new feed additive which results in increased lean growth and improved feed system efficiency. Pigs fed ractopamine require higher dietary levels of essential amino acids to achieve optimal performance levels and economic returns. The marketing systems premium for carcass leanness also impacts the optimal dietary lysine as higher dietary levels are required to maximize carcass leanness versus live weight growth. The optimal digestible lysine levels are those which maximize daily returns above feed costs. The daily gross return is the sum of the daily carcass lean gain and carcass fat gain times their respective value per unit weight. Daily feed costs include the costs of all ingredients, processing costs, and the cost of ractopamine premix.