EFFECTS OF FEEDING A RETURN CHEWING GUM PACKAGING MATERIAL MIXTURE ONPERFORMANCE AND CARCASS CHARACTERISTICS OF FEEDLOT CATTLE

Seventy-two Simmental-cross growing steers (219 +/- 2.4 kg initial BW) were used in a randomized complete block design to evaluate the effec ts of feeding a return chewing gum/packaging material mixture (G/P) on feedlot performance, carcass characteristics, sensory attributes of m eat, and mineral content of beef liver and muscle. Animals were allott ed by weight to 12 pens (six/pen). Each pen was assigned one of three dietary treatments: 1) 0% G/P (control), 2) 20% G/P, or 3) 30% G/P (% G/P on a DM basis). Steers were fed their respective diets for an 84-d growing phase and a 112-d finishing phase. The G/P replaced corn sila ge and corn in the growing and finishing phases, respectively. Eightee n steers (six/treatment) were randomly selected for slaughter at the e nd of the finishing phase, and carcass measurements, sensory attribute s of meat, and mineral content of liver and longissimus muscle were me asured. During the growing phase, steers fed G/P-containing diets had improved (P < .01) daily DMI, ADG, and gain:feed ratios (G:F) compared with controls. However, due to compensatory gain and the fact that G/ P replaced corn in the finishing phase, control steers had increased ( P < .01) ADG and improved (P < .05) G:F vs steers fed G/P-containing d iets. Over the entire study (growing and finishing phases) steers fed diets containing G/P and the control had similar performance. Amount o f G/P in the diet had no effect (P > .05) on carcass characteristics. Steaks from steers fed 20% G/P had improved (P < .01) juiciness compar ed with steaks from steers fed 30% C/P; no other sensory attributes we re affected. Aluminum, zinc, and barium content of longissimus muscle and liver were within the normal expected ranges for all treatments. T hese data indicate that G/P can safely replace at least 30% of growing and finishing diets without impairing feedlot performance or carcass merit.