An ovine hepatotoxicosis caused by the plant Pteronia pallens (Asteraceae) L.f

The hepatotoxicity of Pteronia pallens was demonstrated in 5 sheep which developed lesions that ranged from centrilobular necrosis to diffuse hepatocellular degeneration. Botanical, clinical and pathological data are given and the lesions are briefly compared with those caused by other hepatotoxic plants in South Africa.     

An ovine hepatotoxicosis caused by the plant Hertia pallens (DC.) Kuntze (Asteraceae)

A field outbreak of Hertia pallens poisoning in sheep is described. The hepatotoxicity of the plant was experimentally demonstrated in 7 sheep which developed lesions that ranged from a diffuse degeneration to centrilobular necrosis. These lesions occasionally extended to the midzonal area of the lobules. In addition to a lung oedema, a diffuse mononuclear interstitial pneumonia was present in 3 of the sheep. Botanical, clinical and pathological data are given.     

Clinical pathological changes in gousiekte, a plant-induced cardiotoxicosis of ruminants

Twenty sheep were dosed with either Pachystigma pygmaeum or Fadogia homblei belonging to the Rubiaceae. The experimentally-induced cardiotoxicoses were monitored by various clinical pathological parameters and heart function tests. Elevated AST (aspartate transaminase) activity in the serum proved to be a more reliable indicator of cardiac damage in gousiekte than either LD (lactate dehydrogenase) or CK (creatine kinase). Persistent increases of AST activity were recorded from c. 14 days after commencement of dosing, and this activity sometimes peaked as late as 30 days after the dosing had ceased. Tachycardia and diminished heart function were registered only terminally. Lesions of gousiekte were present in all the sheep that were exposed to the plants. In a field outbreak of P. pygmaeum, where 60 out of 90 sheep died, 14 out of the 15 animals examined had increased AST levels compared with none of the 15 controls. These results indicated that increased enzyme levels can be of use to identify affected animals during latency in a natural outbreak of gousiekte.     

A tremorgenic mycotoxicosis of cattle caused by maize sprouts infested with Aspergillus clavatus

An outbreak of disease affecting a herd of 16 dairy cattle which were fed mouldy, sprouted maize is described. Eight of the cattle were affected, 5 of which died. The clinical signs included muscular tremors, hypersensitivity, ataxia, anorexia and salivation. Aspergillus clavatus was the only fungus isolated from the sprouts. Clinical signs that were indistinguishable from those in the field outbreak were reproduced by dosing the mouldy maize sprouts to a steer and a sheep, and by dosing another sheep with maize inoculated with a pure culture of A. clavatus isolated from the mouldy maize on the farm. Light microscopical examination revealed neuronal degeneration and necrosis in the midbrain, medulla oblongata and spinal cord of all 3 of these animals. The disease is clinically and pathologically indistinguishable from the disease caused by the ingestion of sorghum beer residue, and in certain respects it is similar to toxicoses caused by the ingestion of wheat sprouts and malt sprouts infested with A. clavatus.     

Hepatogenous photosensitivity diseases in South Africa

Various hepatogenous photosensitivity diseases of ruminants in South Africa, caused by plants, fungi and an alga, are described. Information is given on botanical, mycological, toxicological, clinical and pathological aspects of the diseases. The intoxications were grouped according to the primary site of involvement and type of lesions in the liver. The aetiology, pathogenesis, and diagnosis of these conditions received special attention and the most important features are illustrated in colour.     

Resistance of sheep to poisoning by The plant, Marticaria nigellifolia DC

The plant, Matricaria nigellifolia, was dosed to 2 sheep to reinvestigate whether or not sheep are susceptible to pushing disease ("stootsiekte"). Each sheep received a total dose of 370 g/kg of the milled, dried plant from a batch that had caused pushing disease in cattle when given at doses as low as 10 g/kg. Neither of the sheep developed clinical disease over the trial period of 60 days, and necropsies revealed no macro- or microscopical lesions. Sheep are apparently resistant to pushing disease, which supports previous findings.