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Corn distillers dried grains with solubles (DDGS) are known to negatively impact carcass yield and fat quality due to their high neutral detergent fibre (NDF) and unsaturated fatty acids content. Thus, finishing pigs may need to be switched from diets containing DDGS to corn–soybean meal (CSBM) diets before marketing. The objective of this study was to understand the impacts of switching from DDGS to low NDF diets at increasing intervals starting 76 days before harvest on growth, carcass characteristics, and carcass FA composition. For this purpose, a total of 860 finishing pigs (of 66.2 kg of body weight, BW) were used for the trial. Pens of 23 to 25 pigs were blocked by BW and allotted to one of five dietary treatments (n= 7 pens) differentiated by the DDGS withdrawal period: 76, 42, 27, 15, or 0 days before harvest. Diets contained 40% DDGS from 22 to 66 kg before the experiment, 0% or 35% DDGS during the experiment from 66 to 82 kg, and 0% or 30% DDGS until the completion of the trial. Diets were not balanced for net energy.
Results showed that, for the overall period, as the withdrawal period increased, average daily gain (ADG) and final BW linearly increased and average daily feed intake and feed efficiency (G:F) quadratically improved. There was a linear increase in hot carcass weight (HCW), with a marginally significant linear increase in carcass yield with an increasing withdrawal period. Loin depth and lean percentage did not demonstrate any evidence for treatment differences. Backfat linearly increased with an increasing withdrawal period. Finally, iodine value (IV) of belly fat was linearly decreased with an increased withdrawal period.
In conclusion, switching from a DDGS-based diet to a CSBM-based diet for longer periods before slaughter increased ADG and improved G:F, resulting in increased HCW. After diets were switched from DDGS to CSBM, pigs demonstrated an increase in intake, likely due to the ability to consume high volumes of feed after consuming high fiber (DDGS) diets. Belly fat IV was decreased as the length of time after the dietary change was increased, with the lowest IV resulting from pigs that consumed CSBM for the entire experimental period.
Lerner AB, Tokach MD, DeRouchey JM, Dritz SS, Goodband RD, Woodworth JC, Allerson M. Effects of switching from corn distillers dried grains with solubles-to corn-and soybean meal-based diets on finishing pig performance, carcass characteristics, and carcass fatty acid composition. Translational Animal Science. 2020; 4(2): 715-723. https://doi.org/10.1093/tas/txaa070
