Trachyandra species

Abstract

DISTRIBUTION: T. laxa is mainly found in grassveld areas, while T. divaricata grows in the sandy soil and dunes of the south-western areas of the Cape Province.

BOTANICAL DESCRIPTION: General: These are perennial plants with underground rhizomes. Leaves: Numerous soft succulent leaves arranged in rosettes Flowers: Large, branched upright inflorescences with small white flowers. T. laxa is a tumbleweed.

TOXIC PRINICIPLE: •Unknown •The plants are palatable early in the growing season and outbreaks occur in the overgrazed areas during the dry months. • The incidence of the disease ceases soon after the onset of good rains and improvement of pastures.

SYSTEMS AFFECTED: Central nervous system.

CLINICAL SIGNS: •Initially the animals move with difficulty, show over-knuckling, hypersensitivity and tremor. •Progressive ascending paresis and paralysis follow and animals remain in sternal recumbency. •Affected animals starve or die of exposure 1 - 3 months later. •In horses, the signs may disappear after light exercise, though the animals tire easily and show dyspnoea.

NECROPSY: •Usually no macroscopical changes present •Microscopically a khakhi-brown pigment is visible in the cytoplasm of the larger neurones of the brain, spinal cord and ganglia.

TREATMENT MANAGEMENT: With proper feeding or with improved grazing, complete recovery from the early signs may occur after six months, but in some cases only partial recovery occurs and the animal retains a paretic limb.