Poaceae

Abstract

DISTRIBUTION: Widespread grasses that occur naturally in all kinds of veld types.

BOTANICAL DESCRIPTION: Mostly grasses (monocotyledons) that have severely barbed awns or seeds. Usually these awns help to distribute the seeds of the plant by clinging to people or to animals that are passing by and who will then get rid of it somewhere else.

TOXIC PRINCIPLE: • The seeds, and especially awns, of many grasses are severely barbed (often only seen microscopically). • Following penetration of any tissue, a forward, self-propelled action of the awn occurs and it migrates around in the mouth and subcutaneous tissue. • When they get lodged, and penetrate the mucous membrane of the mouth they cause trauma and secondary bacterial infection.

SYNDROMES: Mechanical irritation.

SYSTEMS AFFECTED: Gastro-intestinal system.

CLINICAL SIGNS: Small stock: Problems are caused by Themeda triandra and Heteropogon contortus in the mouths of small stock if they are forced to eat it in milled veld hay or during feed shortages. Pets: • Setaria verticillata is a fine, soft annual weed often associated with disturbed soil and shade. • It has typical bottle-brush Setaria seeds with numerous microscopic barbs on the fine awns. • It sticks to and severely mats the coats of dogs and cats - especially those with long, soft hair. • On grooming itself to remove the seed, the awns lodge in the mouths of the animals and penetrate the soft mucous membrane which can lead to pharyngitis.

TREATMENT: The awns can be mechanically removed – even by forceps if it is lodged in the mouths of the animals.