Neurotoxicity in calves induced by the plant, Nierembergia hippomanica Miers var. violacea Millán in South Africa.

The plant Nierembergia hippomanica var. violacea has been incriminated in field outbreaks of neurotoxicity in calves in the Free State Province. Hepatotoxicity and electrocardiogram (ECG) deviations were induced in a sheep dosed with 5 g/kg dried plant material on four consecutive days. A calf dosed with 2.5 g/kg dried plant material, on two consecutive days, did not show overt clinical changes. Voluntary ingestion of approximately 30 g/kg fresh flowering plants by a second calf resulted in nervous signs characterized by chewing motions, protrusion of the tongue, dysphagia, hypermetria, ataxia, paresis and lateral recumbency. Salivation, dehydration and cardiac irregularities completed the clinical picture. Clinical chemistry changes revealed muscle damage and increased serum urea and creatinine concentrations indicative of kidney involvement. This is the first confirmed outbreak of Nierembergia hippomanica var. violacea intoxication of stock in South Africa.