Wright buckwheat

Eriogonum wrightii

Description

Wright buckwheat is a low, highly branched, perennial shrub that grows from a robust taproot and a reddish woody base. The oblong leaves are about 1 inch long and are scattered on many stems. When in flower (August to October), the plant appears as a white bouquet that turns reddish-orange in cool weather.

Habitat

The plant generally grows on rocky slopes and foothills in the low mountains of West Texas. It has been recorded in the Trans- Pecos, Edwards Plateau and Plains regions.

Toxic Agent

The toxin involved in buckwheat poisoning is a photodynamic agent. The animal absorbs this substance directly from its digestive tract (primary photosensitization) and can transfer it to calves through the milk. Once this process occurs, the animal becomes hypersensitive to sunlight.

Signs of Livestock Ingestion

Signs of photosensitization include: • Reddening of light-colored skin, especially thin-skinned areas and those having thin or no hair, such as the muzzle, udder and vulva. • Skin inflammation followed by swelling, blisters, fluid seepage and usually sloughing of the skin. • For dark animals, the skin is not blistered or sloughed, but it usually becomes thickened and crusted.

Management Strategies

Animals with primary photosensitization (as compared to hepatogenous photosensitization) seldom die if proper precautions are taken. As soon as clinical signs begin, place affected animals in the shade with feed and water. Painting or spraying the affected skin with methylene blue solution or some other nontoxic dye helps protect the areas from further sun exposure. Move unaffected animals to a new pasture, free of the plant causing the photosensitization.