Selenium Supplements in Salt for Sheep

Trace mineral salt supplemented with 0, 30, 65 or 170 ppm selenium (from sodium selenite) was offered ad libitum to ewes and their lambs consuming low-selenium (Michigan) or adequateselenium (North Dakota) diets. Although overt lesions of muscular dystrophy were not observed, the low erythrocyte glutathione peroxidase activities, low plasma selenium concentrations, and elevated plasma creatine phosphokinase activities in Michigan lambs unsupplemented with selenium provided evidence of incipient selenium deficiency. Selenium supplements restored these values to normal. Tissue selenium concentrations were also increased in Michigan lambs, but even the 170 ppm supplement did not produce selenium accretion above that in North Dakota lambs fed diets which were naturally adequate in selenium. Thirty to 65 ppm supplemental selenium in salt proved safe and effective in preventing subclinical selenium deficiency.