EFFECT OF GRAZING LEGUMES OR GRASS FORAGES WITH OR WITHOUT CORN SUPPLEMENATION ON ANIMAL PERFORMANCE AND MEAT QUALITY OF FORAGE-FINISHED BEEF. A. Wright, J. Andrae, M. Miller, P. Gunter, C. Fernandez Rosso, E. Pavan and 1Clemson University, Clemson, SC 29634 Angus x Hereford steers (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 105 d when finished to an equal time endpoint. 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 recommend 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. Introduction: Forage-finished beef remains a niche market in the U.S., but it continues to grow each year in terms of consumer demand. This is related to perceived human health and environmental benefits (low-input production systems). There are also studies (Franzluebbers, 2007 and Russelle et al., 2007) suggesting economic and environmental benefits when crops are integrated with forage based livestock systems. Forage finishing beef with our without corn supplementation, provides an opportunity for producers to integrate livestock and crops. The primary human health benefits associated with finished beef when compared to feedlot-finished beef are less saturated fat, improved n-6:n-3 fatty acid ratio, and a higher percentage of conjugated linoleic acids (CLA) (French et al., 2000; Pavan et al., 2008; Fincham et al., 2009.) Duckett et al. (2009) reported that meat from forage compared to concentrate diets had higher concentrations