A sudden 18% mortality occurred in a herd of range beef cattle in excellent condition at the beginning of the winter in May/June 2000 on two adjoining farms in the Kalahari sandveld of southern Africa. More than 200 animals died with signs of extensive renal failure from 3 days to 3 weeks after suspected exposure. Investigations indicated a nephrotoxic aetiology, but none of the known nephrotoxic plants or agents could be incriminated (Kellerman et al., 1988). A small perennial shrub, identified as Nolletia gariepina (Asteraceae) grew extensively in the camps where the affected animals had grazed and was one of the dominant shrubs that had been eaten. According to the stockman on the second farm, the cattle immediately started to graze on N. gariepina shrubs as soon as they were released on to the grazing. Feeding of the shrubs to a steer under experimental conditions caused the same nephrotic syndrome clinically, as was observed in the field cases. Post-mortem and histopathological lesions were identical to those found in the field cases. Dosing of the shrubs via rumen fistule to two sheep caused severe depression, abdominal pain and anorexia, and on postmortem histopathological examination, the lesions were similar to the field cases. Guinea pigs were also dosed with material from the shrub, and histological lesions found in the kidneys of affected guinea pigs resembled those from the field cases as well as the other experimental animals. This is the first confirmed report of toxicity due to the ingestion of this shrub.
展开▼
