Twenty Angus cross heifers were fed a complete diet which contained 0.07 mg selenium/kg dry matter. Thirteen were injected subcutaneously with barium selenate at a dose rate of approximately 1 mg selenium/kg bodyweight and seven remained untreated. All the heifers were slaughtered during the following 121 days, the last of the treated group 119 days after injection. Glutathione peroxidase activity in blood increased within four weeks of administration and remained high thereafter. The selenium dependent glutathione peroxidase activity did not increase in liver kidney or muscle. The concentrations of selenium in the blood, liver and muscle were increased significantly from 30 days until 119 days. Between 76 and 99 per cent of the selenium injected remained at the site of injection.