To identify an antioxidant system, Se and Vit. E were administered into Hanwoo young sire and the effects of administration on blood components(Se, Vit. E, chemical values, estradiol-17 $eta$, testosterone) were examined. The 16 heads ranging from twenty to thirty two months of age were randomly assigned to control group, Se-administered group(Se-group), Vit. E-administered group(Vit. E-group) and Se and Vit. E administered group(Se and Vit. E-group). Each reagent (Se : 0.1 mg, Vit. E . 1,500IU, Se+vit. E : 0.1 mg+1,500IU per kg of body weight, respectively) administered 3 times every 30days by intramuscular injection. Se concentration in serum was higher in Se-group and Se and Vit. E-group than in control group and Se and Vit. E-group also was higher than Vit. E-group(p<0.05). Although all Se-, Vit. E-administered groups were a little higher than control group, the injection of Se and Vit. E were not significant effect on Vit. E concentration in serum(p>0.05). All groups showed significant variance by periods, but there were not significantly different among groups in blood chemical values. The estradiol-17 $eta$ concentrations of all Se-, Vit. E-administered groups were a little higher than those of control group, but there were not significant(p>0.05). There have no significant difference among groups in testosterone concentration. These results indicate that the administration of Se, Se + Vit. E increase Se concentration in Hanwoo young bull.

Keywords: selenium, vitamin E, blood component, antioxidant, Hanwoo