MUSCULAR-DYSTROPHY OF THE DIAPHRAGMATIC MUSCLES IN HOLSTEIN-FRIESIAN COWS

Six Holstein-Friesian cows suffering from recurrent rumenal tympany we re pathologically investigated. Macroscopical lesions associated with the clinical symptoms were confined to the diaphragmatic muscles which were pale, and stiff on palpation. Histopathological examination reve aled various degenerative changes in diaphragmatic muscles as follows: variation in muscle fiber diameter, vacuolar and hyalinized degenerat ion of muscle fibers, fiber splitting, central core-like structures, s arcoplasmic masses and ring fibers. These characteristic features in t he present cases were consistent with dystrophy of the diaphragmatic m uscles in Meuse-Rhine-Yssel cattle. From these observations, it is con firmed that muscular dystrophy of the diaphragmatic muscles dose occur in Holstein-Friesian cows, although a genetic mode was not proven.