This experiment was conducted to determine the effects of dietary copper levels on performance, carcass characteristics, and economical analysis in Hanwoo steers. Fifteen Hanwoo steers weighing about 300 kg were randomly allotted into one of three treatments. The three treatments consisted of Control(7 mg Cu/kg feed), TI(12 mg Cu/kg feed) and TII(17 mg Cu/kg feed). Copper was formulated with concentrate from copper sulfate(CuSO4) and animals were fed the diets supplemented with copper from 300 kg untill about 630 kg of body weight.Dietary copper levels did not affect daily weight gain, feed intake and feed efficiency during the whole feeding period. Dressing percentage, rib eye area and backfat thickness were not different between animals fed the diets supplemented with copper. Animals fed the diets supplemented with copper received the same B grade in yield grade.Animals fed the diets supplemented with copper received same marbling score. Beef color, fat color, texture and maturity were not affected by Cu supplementation in diet. Animals received the same first grade between treatments in quality grade. Animals fed the diet supplemented with 12 mg of copper per kg diet was higher in profit by 13.3% than animals fed the control diet.According to these results, it may be concluded that performance, yield and quality grade were not affected by the Cu levels of 7 to 17 mg per kg feed but crude income was enhanced when Hanwoo steers were fed the diet containing 12 mg Cu/kg feed.

This experiment was carried out to investigate the effects of dietary vitamin C and E on lipid oxidation and stability of color in Hanwoo steer beef. Thirty seven Hanwoo steers were randomly assigned to one of four treatments. The four treatments were control(vitamin E 20IU/kg feed), vitamin C(vitamin C 0.1%/kg feed and vitamin E 20IU/kg feed), vitamin E(vitamin E 220IU/kg feed) and vitamin C plus E(vitamin C 0.1%/kg feed and vitamin E 220IU/kg feed). Hanwoo steers were fed the experimental diets for 3 months at the last finishing period and pH, color, TBARS, concentration of myoglobin, water holding capacity, reduction by heat, drip loss and purge loss of longissimus dorsi were analyzed at 1, 3, 5, 7 and 10th day of storage, respectively. pH value, Hue angle, metmyoglobin concentration, TBARS, drip loss and purge loss in longissimus dorsi were increased as the storage period elapsed. However, water holding capacity in longissimus dorsi was decreased as the storage period elapsed. The animals fed the vitamin C plus E diet were higher in pH value and oxymyoglobin concentration, and lower in metmyoglobin concentration than in those fed the other diets during the whole storage period and lowest in TBARS. TBARS and Hue angle in longissimus dorsi were lower(P < 0.05) in the animals fed the vitamin-supplemented diets than in those fed the control diet. Reduction by heat in longissimus dorsi was higher(P < 0.05) in the animals fed the diets supplemented with vitamin E or vitamin C plus E than in those fed the control diet or vitamin C-supplemented diet.According to these results, it may be concluded that feeding the diets containing 0.1% vitamin C or 220IU vitamin E per kg feed or the diet mixed 0.1% vitamin C with 220IU vitamin E to Hanwoo steers can retard lipid oxidation of longissimus dorsi and stabilize beef color.