An abnormality of the bone marrow associated with vitamin E deficiency in sheep.

1. Sheep fed on a maintenance ration of wheaten-hay chaff or of wheaten-hay chaff-lucerne-hay chaff (I : I, W/W) became deficient or incipiently deficient in vitamin E. 2. Degenerative changes were observed in bone marrow and muscle, and liver function was imparied in some animals. These abnormalities were not influenced by the vitamin B12 status of the animals or by a shortage of cobalt in the rumen. 3. Plasma ascorbic acid levels may not have been optimum, and folic may not have been fully utilized by some sheep. 4. Liver function responded faily rapidly to alpha-tocopheryl acetate, but skeletal muscle had not returned to normal after 28 weeks of treatment. A variable trend towards normal cellularity was found in bone marrow following supplementation with alpha-tocopheryl acetate. 5. A secondary deficiency or, alternatively, inefficient excretion or metabolism of a toxic material, may occur in vitamin E deficiency as a result of degenerative changes in the absorptive or excretory areas of the intestinal tract and be responsible for the bone marrow abnormality.