There may be economic advantages for using by-product ingredients when they are cost-effective, but, high amounts of dietary fiber at finishing phase may negatively affect carcass yield. Two experiments were conducted to determine the duration of high-fiber ingredient removal from finishing pig diets before marketing to restore carcass yield and carcass fat iodine value (IV), similar to pigs continuously fed a corn-soybean meal diet.
In experiment 1, 288 pigs (38.4 ± 0.3 kg of initial BW) were used in an 88-d study and fed either a low-fiber corn-soybean meal diet from day 0 to 88 or a high-fiber diet containing 30% corn distillers dried grains with solubles (DDGS) and 19% wheat middlings until day 20, 15, 10, 5, or 0 before slaughter. Then, switched back to the low-fiber corn-soybean meal diet. The diets were not balanced for net energy. Those pigs continuously fed the high-fiber diet tended to increase the average daily feed intake, and decrease both, Gain: Feed ratio (G:F) and carcass yield compared with pigs fed the low-fiber corn-soybean meal diet (from day 0 to 88). Throughout, pigs continuously fed the high-fiber diet had greater IV of jowl, backfat, belly, and ham collar fat than those fed the low-fiber corn-soybean meal diet. As days of withdrawal increased, pigs previously fed the high-fiber diet had a quadratic increase of carcass yield. Pigs continuously fed the high-fiber diet had heavier full large intestines (hot carcass weight percentage) than pigs fed the corn-soybean meal diet. Increasing the withdrawal time, the weight of full large intestine linearly increased and the belly fat IV tended to improve. In experiment 2, a total of 1,089 pigs (44.5 ± 0.1 kg of initial BW) were used in a 96-d study with the same dietary treatments as in experiment 1 with an exception. The pigs were fed the high-fiber diet until day 24, 19, 14, 9, or 0 before slaughter and then switched to the corn-soybean meal diet. Results indicated that pigs provided constantly the high-fiber diet had decreased average daily gain and G:F compared with those fed the low-fiber corn-soybean meal diet. Feeding the high-fiber diet and then switching to the low-fiber corn-soybean meal diet, tended to linearly improve G:F as increasing withdrawal period. Pigs fed the high-fiber diet throughout decreased the hot carcass weight percentage compared with those fed the low-fiber corn-soybean meal diet; which tended to increase quadratically as withdrawal period increased.
In conclusion, switching from a high-fiber diet to a corn-soybean meal diet for up to 24 d before market increased carcass yield (experiment 1) or carcass weight percentage (experiment 2) with the improvement most prominent during the first 5 to 9 d after withdrawal. Although reducing high-fiber can improve carcass fat IV; none of the withdrawal strategies restored it to levels similar to pigs fed the low-fiber diets.
Coble, K. F., DeRouchey, J. M., Tokach, M. D., Dritz, S. S., Goodband, R. D., and Woodworth, J. C. (2018). Effects of withdrawing high-fiber ingredients before marketing on finishing pig growth performance, carcass characteristics, and intestinal weights. Journal of Animal Science, 96(1), 168-180. https://doi.org/10.1093/jas/skx048