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Hypericin and pseudohypericin, bioactive constituents in St. John's Wort (Hypericum perforatum), have been determined in the soft tops of the plant that are most likely to be browsed by foraging livestock. In two consecutive seasons, the hypericin/pseudohypericin concentration in a broad leaf biotype varied from a winter minimum of less than 100 ppm to a(More)
The clinical signs displayed by 96 sheep affected by the nervous syndrome of Phalaris aquatica toxicity and 10 normal sheep injected intravenously with the phalaris alkaloid, 5-methoxy dimethyltryptamine (dose range 0.01 to 5.0 mg/kg), were observed. The distributions of phalaris indole-like cytoplasmic pigments in nuclei of the brains and spinal cords of 9(More)
K ikuyu grass ( Pennisetum clandestinum ) is a perennial pasture species with a spring to autumn growth habit. Although it is usually grazed without ill effect, spasmodic incidents of poisoning in cattle 1 and, to a much lesser extent, sheep 2 and goats, 3 have been encountered. The aetiology and pathogenesis of kikuyu poisoning remains poorly understood.(More)
OBJECTIVE To investigate the clinical effect of administering sufficient Hypericum perforatum to cattle to deliver quadruple the reported oral toxic dose. ANIMALS Thirty-six yearling Hereford (n = 18) and Angus (n = 18) steers. DESIGN A series of six experiments was conducted, each using 12 animals in a 2 x 2 factorial design, with two breeds of cattle(More)
Many of the nervous and muscular locomotor disorders that affect sheep throughout Australia are commonly referred to as "staggers" syndromes. The range of clinical signs displayed by sheep suffering these disorders is sufficiently diverse to enable each syndrome to be graded into one of 5 progressive clinical groups. The first group, the limb paresis(More)
Twenty outbreaks of Phalaris aquatica "sudden death" syndrome in sheep were investigated between 1981 and 1991. Four were confirmed and one was suspected, to be a cardiac disorder; 5 were confirmed and 3 were suspected, to be a polioencephalomalacic disorder; the aetiology of the remaining 7 outbreaks could not be determined. Potentially toxic levels of(More)
There have been anecdotal reports since 1962 of 'staggers' in sheep grazing Romulea rosea infested pastures, but this is the first detailed account. In September 2005, a locomotor disorder developed in 12 of 120 Merino wethers that had grazed R. rosea infested pasture at Albury, New South Wales, over several months. Affected sheep displayed signs that(More)