Morphological studies on experimental oleander poisoning in cattle

Oleander poisoning has been reported in man and animals. The present experiments address the gross and microscopic changes due to oleander poisoning in cattle. Minimum lethal doses (50 mg/kg) of oleander leaves were orally administered to three calves in a single dose each of the other three animals received the same lethal dose in three equal parts with 24-h intervals. The lesions in the three animals which received 50 mg/kg in a single dose resulted from the direct effect of the toxin on the vascular endothelial bed and demonstrated as petechial and diffused haemorrhages, congestion, oedema, cell degeneration and inflammatory cell infiltration in the lungs, heart, mesentry, kidneys, serosal and mucosal surfaces of omasum, abomasum and the intestine. The lungs also showed atelectasis, emphysema and disseminated intravascular coagulation. On the other hand, the animals which received divided doses showed lesions due to long-term exposure to the toxic agent and/or as the result of tissue ischaemia. The lungs also showed cell necrosis and mononuclear cell infiltration in the interstitial tissue, and some of the cardiac muscle fibres rather showed fibromyolysis and cell infiltration between muscle fibres, epicardium and endocardium. The intestinal villi showed haemorrhagic, degenerative and necrotic changes and the eosinophils were infiltrated in mucosal and submucosal layers of this organ. Multifocal degenerative and necrotic changes with inflammatory cell infiltration were also present in the liver parenchyma.