Performance, carcass yield, and carcass quality characteristics of steers finished on rhizoma peanut (Arachis glabrata)-tropical grass pasture or concentrate

Steers (n = 166) finished on rhizoma peanut (Arachis glabrata Benth.)-tropical grass pasture in Florida and slaughtered at Central Packing, Center Hill were compared with steers (n = 152) finished on a concentrate diet in Texas and slaughtered at Excel, Plainview. Average daily gain during the growing and finishing periods was lower (P 0.001) for forage-finished steers (.49 and 0.94 kg/d, respectively) than for concentrate-finished steers (.78 and 1.33 kg/d, respectively). Forage-finished steers had less fat over the ribeye (8.3 vs 11.4 mm; P 0.01), lighter hot carcass weight (280 vs 346 kg; P 0.001), and smaller longissimus muscle area (70.8 vs 86.6 cm2; P 0.001) than concentrate-finished steers. Yield grade was not different (2.7 vs 2.6; P 0.10), but quality grade was slightly better (low Select vs mid Select; P 0.01) for concentrate-finished steers. Lean color of forage-finished steers was darker (P 0.001) and fat of forage-finished steers had a creamier color (P 0.001), but carcasses were not discounted due to yellow fat color. Shear force values were higher (6.8 vs 4.0 kg; P 0.001) for forage-finished than for concentrate-finished steers. Off-flavors were detected by trained sensory panelists in 36% of forage-finished and 14% of concentrate-finished carcasses, but all at barely detectable levels. This research indicates that steers can be finished on rhizoma peanut-tropical grass pastures, but with some reduction in quality grade relative to concentrate-finished steers. Fat color and off-flavor problems often associated with forage-finishing do not seem to be major concerns when steers are finished on rhizoma peanut. However, dark lean color and poor tenderness of carcasses may reduce beef quality produced on this forage