Effects of Reduced-Fat Modified Distillers Grains with Solubles in Finishing Diets of Feedlot Steers on Carcass Characteristics, Fresh and Processed Beef Quality

Abstract Text: Feeding various concentrations of reduced-fat modified distillers grains with solubles (RFMDGS) in finishing feedlot diets was evaluated using fifty crossbred (Angus x Gelbvieh X Holstein x Jersey) steers (initial bodyweight: 379 ± 32 kg). Steers were randomly assigned to 1 of 4 dietary treatments consisting of 14.93% RFMDGS of dietary dry matter (DMD) with 0.74% corn oil DMD (FF15; 4.58% ether extract (EE)); 15.60% RFMDGS DMD (RF15; 3.92% EE); 30.84% RFMDGS DMD (RF30; 4.79% EE); and 46.27% RFMDGS DMD (RF45; 5.52% EE). Steers were fed 181d using a Calan gate system and were harvested at a commercial abattoir. Hot carcass weight; 12th rib backfat; ribeye area; percent kidney, pelvic, and heart fat; and marbling score were collected 24h postmortem. Strip loins were collected for vacuum purge loss evaluation and fabricated into steaks for drip loss, cook loss, Warner–Bratzler shear force (WBSF), and sensory evaluation. Untrained panelists evaluated cooked steaks on overall liking, flavor liking, texture liking, toughness, juiciness, and off-flavor. Liking ratings were conducted on a 120 point line scale with 120 being strongest like imaginable. Intensity ratings were conducted on a 20 point like scale with 20 being extremely tough, juicy, or intense. Shoulder clods were processed into ground beef and bologna. Untrained sensory panelists evaluated bologna on overall liking, flavor liking, texture liking, toughness, and off-flavor utilizing the same scales as steak sensory. Data were analyzed using the MIXED procedure in SAS with an alpha level of 5%.  Treatment did not affect carcass characteristics (P = 0.27) or moisture loss (P = 0.09). Values for WBSF of FF15 steaks were greater compared to all other treatments (P = <0.01). Treatment did not affect liking ratings (P = 0.07) of steaks.  Subjective steak toughness from FF15 were greater than RF15 (10.78 and 8.77, respectively; P = 0.01). Subjective juiciness of FF15 steaks was greater than RF45 (8.50 and 6.94; P = 0.03). Bologna from RF45 had a greater subjective overall liking and texture liking compared to FF15 (78.14 and 71.63, respectively; P = 0.03; 78.25 and 67.51, respectively; P = <0.01). Subjective toughness of FF15 bologna was greater than all other treatments (P = < 0.01). Treatment did not affect subjective flavor liking or off-flavor (P = 0.22 and P = 0.51, respectively) in bologna. Results indicate feeding 45% RFMDG had no effect on carcass traits, decreased subjective toughness in steaks, and increased overall consumer appeal in bologna.

Keywords: beef, quality, reduced-fat modified distillers grains with solubles