Hereditary dilated cardiomyopathy in Holstein-Friesian cattle in Japan: Association with hereditary myopathy of the diaphragmatic muscles

This report deals with the pathology and genetic basis of dilated cardiomyo pathy in 10 Holstein-Friesian cows aged 3-6 years, a disease similar to tha t reported in Simmental-Red Holstein and Holstein-Friesian cattle in severa l other countries. The main clinical signs were associated with systemic ci rculatory failure, and at necropsy the animals showed cardiomegaly, severe congestion and fibrosis of the liver, and systemic cardiac oedema. Histolog ically, hypertrophy and vacuolation of the cardiac muscle fibres and severe fibrosis were noted. Electron microscopically, the sarcoplasm of the hyper trophic fibres was seen to be filled with fine structures of low electron-d ensity, together with thin filamentous material, suggesting myofibrillar ly sis, The mitochondria, showed increased size, an abnormal cristae pattern a nd vacuolation due to partial loss of cristae. Pedigree analysis of the aff ected cattle indicated an autosomal recessive mode of inheritance, The fami ly line of this cardiomyopathy overlapped with that of hereditary myopathy of the diaphragmatic muscles in Holstein-Friesian cattle, the pathological aspects and inheritance mode of which were reported previously. The availab le evidence suggested a genetic association between these two pathologicall y distinct diseases. (C) 2001 Harcourt Publishers Ltd.