Nutritional Diseases of Sheep

This feed-related malady causes almost sudden death in sheep due to a toxin produced by Clostridium perfringens type D and sometimes type C. The organism appears to be widespread in nature. Under conditions of high carbohydrate consumption or high intake of immature succulent forage, the causative bacteria multiply rapidly and produce an ε toxin that increases intestinal permeability. Protection of lambs is possible by vaccinating twice at least 10 days apart with C perfringens type D toxoid or by administering antitoxin at birth. (See also Enterotoxemias.)

White muscle disease is caused by low levels of selenium and possibly vitamin E. Signs include stiffness (especially in the hindquarters), tucked-up rear flanks, arched backs, pneumonia, and acute death. On necropsy, white striations are found in cardiac, diaphragmatic, and skeletal muscles. Levels of AST and lactic dehydrogenase are increased, indicating muscle damage. Blood levels of the selenium-containing glutathione peroxidase are reduced. Although several feedstuffs are fairly rich in selenium and vitamin E, it may be a good management practice in deficient areas to inject lambs shortly after birth with a preparation of vitamin E and selenium designed for parenteral use. The use of a selenium and/or vitamin E supplemented trace mineral mixture (up to 90 ppm) as the only source of salt fed may be useful as a preventive measure. (See also Nutritional Myopathies in Ruminants and Pigs.)