Impact of three different feeding regimens on performance, microbiology, sensory, and objective characteristics of Florida Brangus beef cattle

Two experiments were conducted to evaluate three typical commercially available feeding regimens and their effects on average daily weight gain, prevalence of E. coli O157:H7, generic E. coli, fecal coliforms, total aerobic bacteria, and parasites in beef cattle. This study also focused on blood chemistry of the animals, the proximate composition of the grass on which animals grazed, animal drinking water, animal feed, the resulting carcass characteristics, pH, objective color characteristics and sensory attributes of steaks collected from the short loin of the carcasses. Sixty Florida Brangus steers, where 30 steers with an average age of 17 months were used for Experiment One, and 30 steers with an average age of 9 months were used in Experiment Two. Steers in both experiments were assigned randomly to one of three feeding regimens: (1) Super 12, a non medicated concentrate, plus bahiagrass, (2) B-80, a medicated concentrate containing lasalocid, plus bahiagrass, and (3) bahiagrass only (Grazers). Cattle fed Super 12 concentrate had a higher average daily gain (ADG) and reached the target slaughter weight two and three months earlier than cattle fed B-80 and grazer cattle in Experiments One and Two, respectively. Super 12 cattle had significantly higher (P < 0.05) carcass weights when compared to grazer cattle in Experiment One, and B-80 and grazer cattle in Experiment Two. No E. coli O157:H7 nor Salmonella spp. were detected in any of the fecal samples analyzed in both experiments. The cattle fed the two concentrates had significantly lower coccidia parasites in Experiment One but not Experiment Two when compared to grazer cattle. The proximate composition of the grass was similar (P > 0.05) for all treatments. Objective color, pH, and Warner Bratzler shear force were similar (P > 0.05) for all treatments. In Experiment One sensory panelists detected significantly lower (P < 0.05) overall tenderness in steaks from Super 12 fed cattle when compared to grazers. Panelists also detected significantly lower (P < 0.05) connective tissue in steaks from the grazer cattle when compared with steaks from Super 12 and B-80 fed cattle. In Experiment Two, panelists detected significantly lower (P < 0.05) juiciness in steaks from Super 12 and B-80 fed cattle when compared to steaks from grazer cattle. Data in this study demonstrated that beef cattle grazing bahiagrass and supplemented with Super 12 can be raised in a shorter amount of time and produce steaks acceptable in meat quality and palatability to consumers.