Animal Industry Report

Extension Number

ASL R2453



Summary and Implications

Growth and performance of 40 Yorkshire pigs (74.8±9.9 kg or 164.9±21.8 lbs), 20 pigs from a line selected for low residual feed intake for 5 generations and 20 pigs from a control line, was observed while fed on either an ad libitum or NRC maintenance (weight-stasis ration) basis over a 6 week period. The aim of the later diet treatment was to keep pigs at a constant weight for six weeks. In the ad libitum treatment, there was no difference in initial or in final body weights of these pigs. However, the select line ad libitum pigs consumed 9% less feed over this period. Pigs on the weight stasis treatment were targeted to maintain constant body weight throughout the trial, but this was difficult to obtain for the select line which was slightly heavier than the control line at the end of the experiment, despite consuming 10% less feed than the control line during the 6 week trial. These data show that the line selected for low residual feed intake is more efficient under both ad libitum feeding and restricted feeding.

Copyright Holder

Iowa State University