Animals, Housing and Husbandry. A total of 72 gilts were used, offspring of Newsham XL terminal sires on Newsham US parent gilts. They were blocked by weight into two rows of twelve adjacent pens separated by a central corridor in the same wing of the Purdue University Swine Evaluation Unit. Each pen (6 × 10 ft) housed 3 pigs and had fully-slatted floors, a single drinker, and a single-space feeder. Both water and feed were available ad libitum. The pens were randomly assigned within block to one of two treatments, when they had reached an average bodyweight of 188.5 lb, for the four weeks prior to slaughter; 1) finishing feed plus ractopamine (9 g/ton –19.2% CP), 2) finishing feed alone (19.2% CP).