Effect of different feed additives on growth performance and blood profiles of Korean Hanwoo calves

This experiment was conducted on 60 Hanwoo calves comprising five feed additive groups, with 12 calves in each group, to determine the effects of additives at pre- and post-weaning on growth performance and blood profile. The groups were control, antibiotic (Neomycin 110 ppm), illite (2%), fermented green tea probiotics (FGTP, 0.5%), and mixed additives (FGTP 0.25%, illite 1% and licorice 0.1%). The calves were offered experimental pellet feeds ad libitum and after one month were supplied with imported timothy hay. They moved freely within the group and suckled their mother's milk during the pre-weaning stage (birth to 3 months) and were separated from their dam during the post-weaning stage (4-5 months). During the pre-weaning stage, the highest average daily gain (ADG) was recorded in the antibiotic- and mixed additive-fed groups followed by FGTP, control and illite groups. In the post-weaning stage, significantly higher total weight gain and ADG were recorded in both the FGTP and mixed additive groups compared to the other groups (p0.05), although hemoglobin and hematocrit values were lower in FGTP compared to control, but similar in mixed additive and antibiotic groups. These results indicate no detrimental effects of feed additives on the blood profile of calves at both pre- and post-weaning age. Serum albumin in post- weaning calves of all feed additive groups were similar but significantly lower (p