INFLUENCE OF SELENIUM AND LINOLEIC ACID ON THE DEVELOPMENT OF NUTRITIONAL MUSCULAR DYSTROPHY IN BEEF CALVES, LAMBS AND RABBITS

Abstract

A study was conducted to assess the effects of dietary linoleic acid and selenium on the development of myopathy in beef calves, lambs and rabbits fed a low-selenium hay. Oral administration of selenium to either ewes (14 mg/week) or their nursing lambs (7 mg/week) resulted in a marked reduction in the incidence of dystrophy in the lambs. Linoleic acid had no inhibitory effect on selenium protectivity, whether given to the lambs or the ewes. Suckling calves of dams fed the dystrophogenic hay developed myopathy similar to that observed in lambs. Eight of the 11 affected calves recovered spontaneously from the disorder without treatment. Oral administration of linoleic acid to calves did not promote a higher incidence of dystrophy or inhibit the protectivity of selenium. In addition, the fatty acid did not appear to affect the recovery process. No muscle degeneration was observed in any of the calves given selenium (5.4 mg/week). No dystrophy occurred in rabbits consuming the low-selenium hay. When 1% linoleic acid was incorporated into the rabbits’ diet, severe muscle degeneration developed within 4–6 weeks and selenium was completely ineffective in preventing the disorder.