Evaluation of feed withdrawal prior to marketing to improve carcass yield and reduce feed cost in finishing pigs

Fasting pigs prior to harvest benefits food safety and pork quality. Studies have examined the effect of feed withdrawal prior to marketing applied on groups of pigs marketed at one time but not across multiple marketing events. Therefore, this study determined the effects of three feed withdrawal times before the first and final marketing event on pig performance, carcass traits, and economic return. A total of 695 finishing pigs (117.6 ± 1.06 kg) were allotted in a randomized complete block design and assigned to 1 of 3 treatments (24 pens per treatment; 9 to 10 pigs per pen). Treatments consisted of 12, 18, or 24 h (including transportation and lairage) of feed withdrawal prior to harvest to determine its effects on hot carcass weight (HCW), carcass yield, and economic costs vs. benefits of pigs marketed at two different marketing events (3 heaviest pigs per pen marketed 14-d prior to the final marketing of all remaining pigs). There were no differences in growth performance during the 14-d period between marketing events. However, pigs with 24 h of feed withdrawal prior to harvest had lower (<i>P</i> < 0.05) live BW at the first marketing event and at both events combined than pigs with 12 h of feed withdrawal. For carcass responses, pigs at the final marketing with 12 h of feed withdrawal prior to harvest had increased (<i>P</i> < 0.05) HCW compared to pigs with 24 h of feed withdrawal, leading to a tendency (<i>P</i> = 0.055) for increased HCW overall for the combined marketing events (0.5 kg heavier). When evaluating carcass yield using live weights at 24 h prior to harvest, pigs in the final marketing group with 12 h of feed withdrawal prior to harvest had greater yield (<i>P</i> < 0.05) than pigs marketed with 24 h of feed withdrawal; however, using live weights 12 h prior to harvest to calculate yield, pigs with 24 h of feed withdrawal prior to harvest had increased yield (<i>P</i> < 0.05) compared to pigs marketed with 12 h of feed withdrawal for both marketing events. There were no differences in backfat, loin depth, and percentage lean between treatments. Feed consumed and cost were reduced (<i>P</i> < 0.05) with 24 h treatment compared to 12 h in the overall period. In conclusion, withholding feed at the first marketing event did not impact pigs' growth performance or HCW. However, carcass yield was affected by the feed withdrawal time prior to harvest, with greater HCW for pigs with 12 h compared to 24 h of feed withdrawal at the final marketing event.