Net energy of diets containing wheat-corn distillers dried grains with solubles as determined by indirect calorimetry, comparative slaughter, and chemical composition methods1

Abstract Feeding diets high in corn distillers dried grains with solubles (DDGS) before market can negatively impact carcass yield, hot carcass weight (HCW), and belly fat iodine value (IV). Two experiments were conducted to evaluate the effects of switching from DDGS-based to corn-soybean meal (CSBM)-based diets at increasing intervals (withdrawal periods) before harvest on finishing pig performance and carcass characteristics. Diets in both experiments contained either 0% or 30% DDGS and were balanced for net energy (NE). In Exp. 1, 985 pigs (initially 99.6 kg body weight [BW]) were used with 12 pens per treatment. The four treatments were increasing DDGS withdrawal periods: 28, 21, 14, or 0 d (no dietary switch) before marketing. All pens were marketed by removing the 17% heaviest pigs 21 d before slaughter and the remaining 83% all slaughtered 21 d later. Overall, there was no evidence for treatment differences on final BW, average daily feed intake, or feed efficiency (G:F;P > 0.10); however, average daily gain (ADG) increased (linear, P = 0.022) and belly fat IV decreased (linear, P = 0.001) the longer pigs were fed CSBM diets. There was no evidence for differences for HCW (P > 0.10); however, carcass yield increased (linear, P = 0.001) with increasing time following the switch to CSBM. Backfat depth decreased and percentage lean increased as CSBM feeding time increased (quadratic; P < 0.05). In Exp. 2, 1,158 pigs (initially 105 kg BW) were used in a 35-d study. There were 15 pens per treatment and four treatments of increasing DDGS withdrawal periods: 35, 28, 14, or 0 d (no dietary switch). All pens were marketed by removing the 15% heaviest pigs on day 28, the 28% heaviest pigs on day 14, and a final marketing of approximately 57% of starting barn inventory. There was no evidence that final BW, ADG, G:F, or HCW differed among dietary treatments (P > 0.10). Average daily feed intake and carcass yield increased and belly fat IV decreased (P < 0.050); the longer pigs were fed CSBM. In conclusion, growth performance was minimally impacted following dietary switch from DDGS- to CSBM-based diets, possibly due to similar dietary NE. For carcass yield and belly fat IV, the optimal time to make a dietary switch from high to low fiber appears to be linear in nature and at least 28 d before marketing.

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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 ◽

10.1093/tas/txaa070 ◽

2020 ◽

Vol 4 (2) ◽

pp. 715-723

Author(s):

Annie B Lerner ◽

Mike D Tokach ◽

Joel M DeRouchey ◽

Steve S Dritz ◽

Robert D Goodband ◽

...

Keyword(s):

Soybean Meal ◽

Average Daily Gain ◽

Experimental Period ◽

Experimental Unit ◽

Net Energy ◽

Finishing Pigs ◽

Withdrawal Period ◽

Carcass Yield ◽

Distillers Dried Grains ◽

Corn Distillers

Abstract Corn distillers dried grains with solubles (DDGS) are known to negatively impact carcass yield and fat quality, thus finishing pigs may need to be switched from diets containing DDGS to corn–soybean meal (CSBM) diets before marketing (DDGS withdrawal). A total of 860 finishing pigs (PIC C48 or L42 × 327; initially 66.2 kg body weight, BW) were used in a 76-day experiment to evaluate the effects of DDGS withdrawal periods at increasing intervals before harvest. Pen served as the experimental unit, and there were seven replicate pens per treatment with 23 to 25 pigs per pen. Pens were blocked by BW and allotted to one of five dietary treatments differentiated by the DDGS withdrawal period: 76, 42, 27, 15, or 0 day before harvest. Diets contained 40% DDGS from 22 to 66 kg prior to 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. Linear and quadratic response to time following dietary switch was evaluated using PROC GLIMMIX. For the overall period (day 76 prior to market to day 0), as withdrawal period increased, average daily gain (ADG) and final BW increased (linear, P < 0.002) and feed efficiency (G:F) improved (quadratic, P = 0.019). Average daily feed intake increased (quadratic, P = 0.030) as withdrawal period increased. There was an increase (linear P = 0.010) in hot carcass weight (HCW), with a marginally significant increase in carcass yield (linear, P = 0.094) with increasing withdrawal period. Loin depth and lean percentage did not demonstrate any evidence for treatment differences (P > 0.132). Backfat increased (linear, P = 0.030) with increasing withdrawal period. Finally, iodine value (IV) of belly fat was decreased (linear, P = 0.001) with 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 dietary change was increased, with the lowest IV resulting from pigs that consumed CSBM for the entire experimental period.

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