Cardiomyopathy associated with a curly hair coat in Poll Hereford calves in Australia

Fifteen newborn Poll Hereford calves from five farms died over a three-and-a-half year period. From birth all calves had a tight, curly hair coat which was not observed on any other calves on these properties. All calves with this phenotype died before reaching six months of age. Seven of the 15 calves were noticed to have exercise intolerance, hyperpnoea and dyspnoea for one to seven days before death. The incidence of additional features of the curly hair coat phenotype is also described. Post mortem examinations conducted on the calves revealed focal, diffuse and pale fibrous streaking of the entire myocardium and vascular congestion of the livers, spleens and lungs. A primary cardiomyopathy was diagnosed on the basis of the clinical and pathological findings. Analysis of the pedigrees of seven affected calves from one farm demonstrated a common ancestor for all sires and dams of affected calves and suggested a simple autosomal recessive mode of inheritance of the syndrome as a reasonable hypothesis for future experimental testing.