Cotyledon orbiculata

Abstract

DISTRIBUTION: Occurs in grassland and bushveld in sandy, well-drained spots.

BOTANICAL DESCRIPTION: General: This is a succulent perennial plant, which grows between 50cm and 1 metre high when in flower. It has thick stems that root everywhere where they touch the soil. Leaves: The fleshy leaves vary greatly in size and shape, from broadly ovate to oblong to lanceolate. They are covered with a thin waxy bloom and usually pale blue-green with red-rimmed margins. Flowers: The waxy tubular flowers, carried in a terminal inflorescence, vary in colour from light orange to pink, but are usually coral-red, and pendulous. All flower parts in fives.

TOXIC PRINCIPLE: • Contains four extremely cumulative bufadienolides, namely: - Orbicuside A, B, C, D. • The flowers are more toxic than the leaves and the toxicity of plants differ both within and between localities. • Soil-type may influence toxicity - e.g. C. orbiculata growing on black clay is less toxic than those plants growing on sandy soils.

SYNDROME: Cumulative bufadienolides (Krimpsiekte)

SYSTEMS AFFECTED: Cardiovascular system.

CLINICAL SIGNS: Cotyledon orbiculata can cause both acute intoxication and krimpsiekte under natural conditions. Krimpsiekte is a disease of small stock (sheep and goats). • Krimpsiekte is basically a paretic syndrome. • Affected animals lag behind the flock. • When forced to move, they tire easily and lie down or stand trembling, typically with the feet together, the back arched and the head low. • The neck may be twisted and the head may dangle loosely as the animal walks.

NECROPSY: Acute poisoning: Nothing specific Histopathology: Thalamic vacuolisation has been reported with krimpsiekte.

TREATMENT: • Acute intoxication: dose 2g/kg activated charcoal. • Large dose is essential. • Adsorption and fixation of excess in rumen. • Even retro-diffusion back from plasma. • Minimize stress to prevent catecholamine release. With krimpsiekte treatment is symptomatic and supportive.