Effect of forage type and corn supplementation on animal performance and meat quality

Angus x Hereford steers (441 ± 24 kg; n = 32) were used in a 2-yr study (2011 and 2012) to examine forage type (legume species, alfalfa and soybeans LG vs. grass species, tall fescue and sudangrass, GR) and daily corn supplementation (0%, NS, vs. 0.75% BW, CS) on animal performance and carcass quality. Steers grazed (May-August) for a total of 98 d and 105 d in 2011 and 2012 respectively. Upon completion of the finishing period, steers were slaughtered and carcass data were collected. Steaks (2.5 cm thick) from the longissimus dorsi muscle (LM) were collected for measurement of proximate analysis and tenderness after different postmortem aging times (2, 4, 7, 14, 28 d). Data were analyzed in a mixed model using a 2x2 factorial arrangement of treatments. Steer was the experimental unit and year included as a random effect. Corn supplementation (CS) increased (P < 0.05) average daily gain (ADG), hot carcass weight (HCW), dressing percentage (DP) and tended (P < 0.06) to increase fat thickness at the 12th rib (FT). CS also increased ( P < 0.05) yield grade (YG) and tended to increase (P < 0.07) quality grade (QG). In terms of forage, LG increased ( P < 0.05) DP and HCW, with a tendency to increase ADG ( P < 0.06). CS resulted in lower (P < 0.05) concentrations of CLA c9t11 and n-3 FA. Steers receiving CS had a higher ( P < 0.05) n-6:n-3 ratio (3.1 vs. 2.4), but both are lower than the 4:1 ratio recommended by health officials. Grazing GR increased ( P < 0.05) saturated FA due to greater (P < 0.05) concentrations of stearic (C18:0) acid. LG forage increased calcium content of the LM. Tenderness was only affected (P < 0.05) by postmortem aging. Grazing legumes during finishing improves HCW and DP, and tends to improve ADG. Corn grain supplementation to grazing steers improved animal performance while not negatively impacting the nutritional qualities of the meat.