A foal, small and jaundiced from birth, succumbed after two months to
chronic hepatic damage which was characterised by fibrosis, biliary du
ctular hyperplasia and the presence of pleomorphic hepatocytes contain
ing either a single large nucleus or multiple nuclei. The fixed liver
contained sulfur-bound pyrroles, which are derived from pyrrolizidine
alkaloids. During pregnancy the pasture was heavily infested with the
pyrrolizidine alkaloid-containing plant, Senecio madagascariensis. The
hepatic disease affecting the foal appears to have been initiated by
consumption of the alkaloids by the mare during gestation, and to repr
esent a rare case of congenital pyrrolizidine alkaloidosis.