Brachyglottis repanda
Bushman’s friend
Shrub or small tree up to 6m, branches densely covered in soft white hairs. Leaves are ovate in shape, 10-25cm long, with obvious veins, dull grey/ green on the top surface, with a white hair covered underside. Flowers are white to creamy white in large drooping panicles exceeding the leaves.
Other tree daisies. Velvet groundsel (Senecio petasitis) looks similar but has ragwort type flowers. Probably poisonous and a noxious weed.
Native in NZ, abundant in the N. Island and as far south as Kaikoura and Greymouth in the S. Island.
Rangiora contains hepatotoxic alkaloids the most significant of which, senkirkine, falls into the category of pyrrolizidine alkaloids. This is present at its maximum concentration in the young growing tips, leaf petioles and in the cortex of thin stems. It is not present in the flowers, or in the mature stems, and is only found in low concentrations in the mature leaves. This toxin causes irreversible hepatic damage, with consequent impaired liver function. It is responsible for altering vitamin A metabolism, which depresses plasma and liver levels of this vitamin. However, such poisoning has seldom been reported in livestock this century.
Toxicity has been demonstrated in all livestock, although cattle and horses seem most affected with sheep being somewhat resistant to the effects of the toxin.
These include the usual symptoms of liver disease such as ataxia and depression. A "drunken" condition has been reported in cattle and horses.
These are as yet not described, but obviously liver lesions of some description may be observed.
This is clearly difficult, with the need to rule out other causes of liver disease, and other liver toxicants such as sporidesmin, copper, phosphorous, iron and phenolics before suspecting pyrrolizidine alkaloid toxicity. Pyrrolizidine alkaloids are also present in plants such as ragwort, which is a more likely cause of animal poisoning in NZ.
Anything that causes signs of liver failure, but narrowed down by the history. These could include facial eczema, and fascioliasis.
Administration of synthetic antioxidants in the diet have been shown to confer a degree of protection in laboratory animals. Symptomatic treatment as clinical signs and conditions indicate.
If rangiora poisoning does occur, the prognosis would be good for acute toxicity. If chronic poisoning occurs, obviously the prognosis would be determined by the degree of liver damage.
Conner H.E. The Poisonous Plants In New Zealand. 1992. GP Publications Ltd, Wellington
Parton K, Bruere A.N. and Chambers J.P. Veterinary Clinical Toxicology, 2nd ed. 2001. Veterinary Continuing Education Publication No. 208
4 October, 2007
