Metabolism of vitamin E in sheep.

I . The metabolism of tritium-labelled tocopherol was investigated in thirty-six wethers and forty-two ewes fed on hay known to produce nutritional muscular dystrophy (NMD). 2. In one experiment, the effect of selenium or vitamin E or both on the metabolism of tritium-labelled tocopherol was studied. No difference was found in the incorporation rate of radioactivity in tissues due to the addition of either of these components. 3. In a second experiment, significantly more radioactivity was found in the tissues of sheep dosed intramuscularly than of those dosed by stomach tube into the rumen. Excretion of radioactivity was rapid when labelled tocopherol was given into the rumen. 4. In a third experiment, the efficiency of vitamin E in preventing NMD in lambs was tested. Supplementation with vitamin E of the diet consisting of NMD-producing hay and given to ewes was ineffective as a prophylactic treatment. Direct administration of vitamin E to the lambs completely prevented the occurrence of NMD. Plasma vitamin E concentrations in the treated lambs were significantly higher than in untreated lambs at weekly sampling over a 4-month period regardless of whether the lambs were born from ewes treated with the vitamin or not.