PSXI-13 Effects of pasture grazing on growth performance and blood composition of Hanwoo steer during the growing stage

Abstract This study investigated the effect of pasture grazing on growth performance and blood characteristics in nine-month-old Hanwoo (native Korean cattle) steers. Thirty one steers were randomly assigned to three groups: (CON) Italian ryegrass and concentrate (1.6% BW) until 14 month of age, (G1) pasture grazing 101 days without concentrate, (G2) pasture grazing 101 days and concentrate (1.6% BW). Initial BW of CON, G1 and G2 were 255 kg, 238 kg and 254kg respectively. Average daily gains were higher in CON (1.02 kg) and G2 (0.92 kg) than G1 (0.62 kg) (p >0.05). Final weight and total weight gain were higher in the feeding concentrate (1.6% BW) groups (Con and G2) compared to the G1. Blood characteristics, such as such as total cholesterol (T-CHO), triglycerides (TG) and non-esterified fatty acid (NEFA) were investigated to test the effects on health and energy metabolism. T-CHO, an index of fat metabolism and liver function, was lower in Con (119.75 md/dL) and G2 (107.13md/dL) than G1 (87.79 mg/dL). TG was higher in Con (21.63 IU/L) than G1(15.14 IU/L) (P< 0.08). NEFA was higher in G2 (384 uEq/L) than other groups (Con 138 uEq/L and G1 225 uEq/L). These results show that concentrates supplementation during grazing period is needed to increase BW of Hanwoo steer in the growing state.