Peripartum heart disease in cows

Summary Thirteen Holstein dairy cows aged 5·1–10·6 years died or were killed as a result of severe illness during the peripartum period, associated with lateral recumbency, moaning, tachycardia and dyspnoea. They were all high milk producers (>9000 kg/year) and had experienced at least three pregnancies. The average duration of the clinical course was 2·5±1·7 days. Electrocardiography revealed marked tachycardia associated with atrial fibrillation or atrioventricular dissociation. Serum clinical chemistry showed severe hypocalcaemia (3·6±1·3 mg/dl) and at necropsy multifocal myocardial necrosis was invariably found. Myocardial necrosis was accompanied by neutrophilic and mononuclear cellular infitrates with interstitial fibrosis. The cause of this lesion was not established.