Effects of distillers dried grains with solubles on growing and finishing steer intake, performance, carcass characteristics, and steak color and sensory attributes

Seventy-two crossbred and purebred beef steers (296 ± 9 kg initial BW) were used in a completely randomized design to determine effects of 30% distillers dried grains with solubles (DDGS; 29.2% CP, 9.7% fat, DM basis) inclusion during the growing or finishing period on DMI, performance, carcass, and meat quality traits. The resulting treatments were 0:0, 30:0, 0:30, and 30:30 (diet DDGS percentage fed during growing and finishing periods, respectively). Steers were individually fed a growing diet (65% concentrate) for 57 d, then acclimated to and fed a finishing diet (90% concentrate) for 80 or 145 d. Dietary ingredients included dry-rolled corn, corn silage, grass hay, concentrated separator by-product, and supplement. Diets included 27.5 mg/kg of monensin and 11 mg/kg of tylosin and were formulated to contain a minimum of 12.5% CP, 0.70% Ca, and 0.30% P. During the growing period, DMI was not different (P greater-than-or-equal 0.63; 10.22 ± 0.23 kg/d; 2.42 ± 0.06% of BW). Steer performance, including ADG (1.75 ± 0.05 kg/d) and G:F (174.1 ± 6.8 g/kg), was not affected (P greater-than-or-equal 0.14) by treatment during the growing period, and final BW at the end of the growing period was not different (425 ± 7 kg; P = 0.99). During the finishing period, DMI was not different (P greater-than-or-equal 0.54; 8.47 ± 0.66 kg/d; 1.57 ± 0.09% BW). During the finishing period, no differences (P greater-than-or-equal 0.22) were observed for ADG (1.54 ± 0.07 kg/d) or G:F (202.4 ± 28.3 g/kg). As a result, final BW was not different (P greater-than-or-equal 0.28; 551 ± 15 kg). Longissimus muscle area (77.8 ± 3.3 cm²), 12th-rib fat thickness (1.26 ± 0.10 cm), and KPH (2.48 ± 0.16%) were not different (P greater-than-or-equal 0.16). There were no differences (P greater-than-or-equal 0.35) in yield grade (3.33 ± 0.17) or marbling (431 ± 21; Small⁰ = 400). Results from the trained panel indicated no differences (P greater-than-or-equal 0.16) in tenderness, which averaged 6.03 ± 0.16 (8-point hedonic scale); however, steaks from steers fed 0:30 or 30:30 tended (P = 0.10) to be juicier and more flavorful than steaks from steers fed 0:0 or 30:0 (6.01 vs. 5.83 ± 0.11; 6.02 vs. 5.89 ± 0.08, respectively). Inclusion of 30% DDGS in the growing period tended to reduce L* (P = 0.08; 48.6 vs. 48.9 ± 0.2) and b* (P = 0.01; 8.24 vs. 8.65 ± 0.18) of steaks. Feeding DDGS during growing or finishing reduced b* (P = 0.02; 8.35 vs. 8.74 ± 0.18) compared with 0:0. Feeding DDGS during the finishing period reduced a* (P < 0.001; 20.1 vs. 22.0 ± 0.24) of steaks. Furthermore, feeding DDGS during growing or finishing reduced a* (P < 0.001; 20.9 vs. 21.7 ± 0.24) compared with 0:0. Feeding 30% DDGS did not affect any performance or carcass characteristics but did influence steak sensory attributes and color.