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The effect of DDGS particle size and pellet quality on grower-finisher pig performance
The objective of the study was to evaluate the effect of further grinding distillers dried grains with solubles (DDGS) and the percentage feed fines on grower-finisher pig performance. A total of 760 mixed sex pigs (28.8 ± 3.1 kg) were housed in a curtain-sided barn with mechanical ventilation and totally slatted flooring. The experimental design consisted of a 2 x 2 factorial design with 2 particle sizes of DDGS (640 vs. 450 µm) and 2 levels of fines (0 vs. 25%). The four treatments were randomly distributed among 40 pens with 10 replicates per treatment. Pigs were fed a common diet containing 30% DDGS and 6.5% supplemental fat in 3 dietary phases grower (1 to 40 d), developer (41 to 83 d), and finisher (84 to 116 d). Of the 6.5% supplemental fat in each diet, 1.5% was added in the mixer and 5.0% was added post-pelleting. Diets were conditioned at 77°C for 45 seconds and then pelleted using a pellet mill equipped with a 3.5 mm x 36 mm die. The fines produced during the pelleting process were separated using a pellet screener and then mixed back with the whole pellets to obtain the desired percentage fines in the final feed. Feeds were delivered and pen feed intake recorded using an automatic feed delivery system (FeedPro). Feed consumption and BW were determined at 1, 18, 40, 83, and 116 d on test and gain to feed (G:F) calculated. Data were analyzed using PROC GLM in SAS. Pen was the experimental unit. Fixed effects included DDGS particle size, percentage fines, and their interaction. The particle size of DDGS did not impact (P > 0.05) overall ADG (836 vs. 842 g; P=0.65), ADFI (2205 vs. 2222 g; P=0.66), or G:F (0.379 vs. 0.379; P=0.95). Diets with 0% fines did not improve (P > 0.05) ADG (843 vs. 835 g; P=0.48), ADFI (2224 vs. 2204 g; P=0.59), or G:F (0.379 vs. 0.379; P=0.97) in comparison to diets with 25% fines. Results indicated that DDGS does not need to be further ground at the feed mill and that up to 25% feed fines could be fed without adverse effects on pig performance.
Keywords: DDGS, particle size, fines, grinding