Clinical case: Outbreak of White Muscle Disease or Nutritional Muscular Dystrophy in calves

An outbreak of White Muscle Disease, WMD, or Nutritional Muscular Dystrophy is reported in a flock of 56 Red Friesian calves, where 18 calves of 4 to 5 months of age died in a period of 45 days. The signs observed were tachypnea, difficulty to walk, tachycardia, dilated jugular veins, temperature 38-39 degrees C. Signs of alterations of the nervous or digestive systems were not observed. Muscles of the hind legs, dorsal and gluteal region were moderate swollen, painful and temperature was increased. In the flock sudden deaths of calves were observed within a few hours after appears the first signs. The blood activity of the selenium (Se) dependent enzyme Glutation peroxidase (GSH-Px) was decreased, indicating a Se deficiency. The serum activity of the enzymes associated to muscle damage, Aspartate Amino Transferase (AST) and Creatin Kinase (CK) were increased. The necropsy findings were cardiac enlargement with hypertrophy of the right ventricle. In the myocardium white fine lines of degeneration and also multiple irregular areas with the same colour were observed. Similar lesions were observed on the skeletal muscles. Histologically the myocardium lesions were eosinophilic and irregular muscular cells, with lost of the striation, segmental destruction, as well as great and pleomorfic nuclei; in addition, the Purkinje fibres presented intense eosinophilia and hyaline degeneration corresponding to degeneration of Zenker. The skeletal muscles also presented hyaline degeneration of Zenker. It is concludes that it is White Muscle Disease associated to deficiency of Selenium or vitamin E. Surviving calves were treated with an intramuscular solution of Se and vitamin E, in dose equivalent to 8 mg of Se and 340 U.I. of vitamin E. The treatment was repeated after 7 days and new cases did not appear.