Materials and Methods
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).