Defining the Optimal Feed Budget System for Terminal-Crossed, Growing-Finishing Barrows

This experiment was conducted to evaluate growth performance and carcass quality measurements in growing-finishing barrows assigned to different feed budget systems. Forty-eight barrows with an initial body weight of 47.3 lb were randomly allotted to one of three different feed budget systems. The experiment was continued until the average body weight was 270 lb, at which time all pigs were slaughtered. Growth performance and real-time ultrasound measurements were taken biweekly, except for the final period, which was 24 days. Carcass tenth-rib backfat and longissimus muscle area measurements were made 24 hours postmortem. Overall, average daily feed intake (ADFI) was affected (P \u3c 0.05) by feed budget with barrows assigned to Budget 2 having the greatest ADFI compared to barrows fed Budget 1 (P \u3c 0.05) and 3 (P \u3c 0.10). There was a trend (P = 0.106) toward an effect of feed budget on average daily gain (ADG). Barrows allotted to Budget 2 had greater overall ADG than barrows allocated to Budget 1 (P \u3c 0.10) and 3 (P \u3c 0.10). Feed efficiency for the overall experimental period was not affected (P \u3e 0.10) by feed budget; however, the comparison of Budget 1 and 2 resulted in a difference in feed efficiency with barrows from Budget 1 having better (P \u3c 0.10) feed efficiency than barrows from Budget 2. Ultrasound and carcass measurements were similar for pigs fed the three feed budget systems. The main effect of feed budget on total body electrical conductivity measurements was only significantly different (P \u3c 0.10) for hot carcass weight. Returns above feed cost and feed cost per pound of gain from 50 lb to market weight were not affected by feed budget. Barrows allotted to Budget 2 had the greatest ADG and hot carcass weight; however, this group also had the greatest ADFI, which resulted in no difference in the return above feed costs or feed cost per pound of live weight gain. In summary, there were no major differences in overall growth performance, carcass characteristics, or return above feed costs in growing-finishing barrows fed different feed budgets