Effect of Increased Average Daily Gain after Removal of Pigs on the Optimal Management of Ractopamine

Purdue Universtiy 2003 Swine Research Report. The economically optimal use of ractopamine (RAC, Paylean) using a stochastic swine growth model has been recently reported (Li et al., 2003). The model derives the optimal dietary lysine, RAC concentration and duration of use, and marketing decisions for late finishing pigs. The model develops a live weight body composition and feed intake curves for each individual pig. The model reproduces the total variation for body weight, carcass composition, and carcass weight at each age. Recent research indicates that if pigs are provided only seven square feet per pig, the removal of the fastest gaining pigs increases the growth rate of the remaining pigs in comparison to leaving the pens intact (Bates and Newcomb, 1997; DeDecker, 2002). This increased growth rate may have an impact on the optimal use of Paylean.