Effects of distillers dried grains with solubles supplementation on yearling heifers grazing Northern Great Plains rangeland: impacts on subsequent feedlot performance and meat quality.

Abstract

Eighty-two yearling crossbred heifers (318.8 ± 1.03 kg) were utilized in a completely randomized design to evaluate the effects of distillers dried grains with solubles (DDGS) supplementation on animal performance, while grazing on rangeland of the Northern Great Plains, and subsequent feedlot performance, carcass characteristics, and meat quality traits. Treatments were: 1) 0% DDGS supplementation (CONT) and 2) 0.6% of body weight (BW) DDGS supplementation (SUP). Heifers received treatments for 70 d (6 June to 16 August) while grazing, and then were acclimated to and fed a common corn-based finishing diet for 109 d. Average daily gain (ADG) of SUP heifers was greater (P ≤ 0.01), resulting in heavier BW (P ≤ 0.03) following grazing compared with CONT heifers. Heifer performance, including ADG (1.91 ± 0.05 kg/d), gain to feed (G:F) (0.15 ± 0.003 kg), dry matter intake (DMI) (12.6 ± 0.20 kg), and final BW (572.4 ± 7.43 kg) were not different (P ≥ 0.13) during finishing. Hot carcass weight (335.7 ± 4.39 kg), Longissimus muscle area (81.30 ± 1.24 cm2), 12th rib fat thickness (1.24 ± 0.06 cm), and kidney, pelvic, heart fat (KPH) (1.85 ± 0.08%) were not different (P ≥ 0.47) between treatments. There were no differences (P ≥ 0.24) between treatments in yield grade (2.9 ± 0.10) or marbling (492 ± 22.3; Small00 = 400). Results from Warner–Bratzler shear force indicated that strip loin steaks from SUP heifers tended (P = 0.07) to have increased tenderness compared with strip loin steaks from CONT heifers (3.3 vs. 3.7 ± 0.12 kg, respectively). Inclusion of 0.6% BW supplementation during grazing increased (P = 0.01) strip loin steak muscle lightness (L*) compared with CONT steaks (46.5 vs. 45.5 ± 0.27, respectively). Strip loin steaks from heifers supplemented DDGS during grazing were perceived to be more tender by taste panelists (P = 0.02) than strip loin steaks from CONT heifers (5.9 vs. 5.5 ± 0.11; eight-point scale). Supplementation of DDGS during grazing improved ADG of yearling heifers with no effect on feedlot performance or carcass characteristics but did improve tenderness and steak sensory attributes.