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Title:Effects of pelleting growing-finishing diets with distillers dried grains with solubles (DDGS) on growth performance, carcass characteristics, and commercial bacon slicing yields of barrows and gilts
Author(s):Overholt, Martin F
Advisor(s):Boler, Dustin D.
Contributor(s):Dilger, Anna C; Stein, Hans H
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
distillers dried grains with solubles (DDGS)
Diet Form
Commercial Bacon Slicing
Abstract:Barrows and gilts (192, initial BW = 25.75 ± 2.29 kg) were allotted to two 24-pen blocks with 2 barrows and 2 gilts per pen. A 2 × 2 factorial arrangement of treatments in a randomized complete block design was used with two diet forms (meal or pellet) and two levels of distillers dried grains with solubles (DDGS, 0 or 30%) resulting in four treatment combinations. Pigs were weighed at the beginning of the experiment and again at the end of each of the 3 feeding phases (d 35, 70, 91). Pigs were slaughtered at the University of Illinois Meat Science Laboratory at the end of the 91 d feeding trial. Full gastrointestinal (GI) tract and GI tract component weights were recorded immediately following evisceration. Carcass characteristics and meat quality were determined after a 24 h chill. Carcasses were fabricated and the bellies were collected for manufacture into bacon. Belly dimensions and flop distance were measured. A fat sample from each belly was collected for fatty acid analysis. Bacon was manufactured at a commercial processor and then returned to the University of Illinois Meat Science Laboratory for further evaluation. Overall ADG was increased (P < 0.01) by 3.2% when pelleted diets were fed. Overall ADFI of pigs fed 30% DDGS was 4.7% greater (P < 0.01) than pigs fed 0% DDGS in meal form diets. Overall ADFI of pellet-fed pigs did not differ (P ≥ 0.19) between the 30% and 0% DDGS diets. Pigs fed 0% DDGS had 2.7% greater (P = 0.02) overall G:F than pigs fed 30% DDGS in meal form diets. There was no difference (P = 0.42) in overall G:F regardless of DDGS inclusion in pigs fed pelleted diets. Full GI tracts of pellet-fed pigs represented 0.33 percentage units less (P = 0.03) of the ending live weight than meal-fed pigs due to decreased (P < 0.01) gut fill. Inclusion of DDGS increased (P = 0.03) full GI tract weight, large intestine weight (P < 0.01), and gut fill (P = 0.02). Severity of parakeratosis of the pars oesophagae was greater (P < 0.01) in stomachs of pellet-fed pigs than in meal-fed pigs, but the magnitude of the difference was likely not great enough to negatively affect drop value of stomachs. There was no effect of DDGS inclusion on overall ADG (P = 0.46) regardless of diet form. Pellet-fed pigs had 2.9% heavier HCW (P = 0.01), 10.4% thicker 10th rib back fat (P = 0.01), and 1.8 percentage unit less estimated lean percentage (P = 0.04) than meal-fed pigs. Bellies from pellet-fed pigs were 5.3% heavier (P < 0.01) but, were not proportionally different (P = 0.55) from meal-fed pigs. There were no differences (P ≥ 0.11) in belly dimensions between meal and pellet-fed pigs. Belly fat iodine value (IV) of pellet-fed pigs was 3.1 units greater (P < 0.0001) than meal-fed pigs. Pellet-fed pigs had heavier belly green weight and those differences persisted throughout processing. Despite pellet-fed pigs having a greater IV than meal fed pigs, there were no differences in commercial bacon slicing yields among treatment groups. Even so, bellies from pellet-fed pigs produced more total bacon slices (P < 0.01) than bellies from meal-fed pigs, but had 3.1% fewer (P < 0.01) slices/kg of sliced belly. Inclusion of DDGS resulted in a 0.32 cm decrease (P < 0.0001) in belly thickness, a 4.97 cm decrease (P < 0.0001) in flop distance, and a 2.8% decrease (P = 0.04) in green weight. Belly fat of DDGS-fed pigs had a 7.1 unit greater (P < 0.0001) IV than pigs fed 0% DDGS diet. There was no effect (P ≥ 0.41) of DDGS on slicing yields. In conclusion, feeding pelleted diets improved growth performance, decreased the weight of the gastrointestinal tract, and increased carcass weight and carcass fatness. The increased carcass weight and fatness was reflected in the fresh bellies; which were heavier and fatter than bellies from meal-fed pigs. But feeding pelleted diets increased belly fat IV. As expected feeding 30% DDGS resulted in bellies that were thinner, had decreased flop distance, and a greater IV than pigs fed 0% DDGS. Despite pelleting increasing belly fat IV 3.1 units compared with meal-fed pigs, there was no effect of diet form on commercial bacon slicing yields. Moreover, even though bellies of 30% DDGS-fed pigs had a 7.1 unit greater IV than 0% DDGS-fed pigs, there was no difference in commercial bacon slicing yields. Overall, pig producers can take advantages in efficiency and rate of gain offered by pelleting growing-finishing diets while increasing saleable pounds of carcass and, bacon manufacturers can use bellies from pigs fed pelleted diets without concern of negatively affecting slicing yields.
Issue Date:2015-10-23
Rights Information:Copyright 2015 Martin Overholt
Date Available in IDEALS:2016-03-02
Date Deposited:2015-12

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