Crotalaria burkeana

Abstract

DISTRIBUTION: Occurs in mixed grassland or open sandy areas. Spreads rapidly in disturbed soil or trampled veld.

BOTANICAL DESCRIPTION: General: It is a woody, much branched perennial herb 30-60 cm in height with white hairy stems. Leaves: The leaves are three (sometimes five) foliate and have long leaf stalks. Hairy, becoming smooth on upper surface later. Flowers: 5 - 12 Pea-like flowers in lax raceme. White, sometimes tinged yellow or mauve with brown or dark blue veins. August - March. Fruit: Inflated oblong hairy pods + 4cm long, containing brown kidney-shaped seeds.

TOXIC PRINCIPLE: • The toxin of C. burkeana is not known, but differs markedly from the effects of the other poisonous Crotalaria spp. • The active principles of Crotalaria spp. worldwide are the pyrrolizidine alkaloids which are mainly responsible for severe liver and/or lung damage in stock.

SYNDROMES: Stywesiekte.

SYSTEMS AFFECTED: Skin and appendages.

CLINICAL SIGNS: Stywesiekte occurs most commonly in cattle, but sheep, goats, donkeys, horses and wild antelope can also be affected. Acute: • Claws/hooves warm to the touch, painful. - Affected stock walk with difficulty, - Lameness (as if walking on eggs!) - All four feet affected. Front legs to the fore, hind legs tucked in under body. - Frequently lies down. - Rises with difficulty. • Can’t get to grazing or water. • Loss in condition, drop in milk production. Chronic condition: (Following the acute attack) • Hoof tissue is stimulated and grows abnormally. • Points of the claw become elongated and turn up. • The stock walk with difficulty.

TREATMENT: Acute: Cold water, symptomatic, provide feed and water. Chronic: Cut/shape the claw.