Characteristics and toxic properties of Lathyrus sativus seed

Grass pea (family FABACEAE Lindl.) infests crops of cereal crops and poses a serious threat to human health and the health of livestock animals. Before the end of flowering, the green mass of the plant is non-toxic and serves as good feed. The danger arises during pod formation and seed development, when toxic alkaloids accumulate in the plant parts. Under the influence of a hot climate, the toxicity of grass pea increases, causing paralysis of the legs when ingested — a disease known as "lathyrism".

Morphology of grass pea and risks for livestock farming

The weed infests crops in the European part (primarily in the southern and south-eastern regions), in the Caucasus, in Central Asia, and in Eastern Siberia. The pods of the plant have an elliptic-oblong, broad-linear shape with two wing-like ridges along the dorsal seam. The seeds are three-sided-angular, wedge-shaped and laterally compressed, with a smooth matte surface and an elongated-oval hilum. The yellow or light-yellow color of the seeds is usually plain, whereas dark seeds have a speckled dark-yellow pattern.

• Seeds per pod — usually 36
• Pod length — 34 cm
• Pod width — 11.3 cm
• Seed diameter — 610 mm
• Symptoms of poisoning — after 3060 days
• Animal mortality — 30% or more

In livestock practice, the most common cases of poisoning are caused specifically by weed seeds. The disease develops latently, and the first signs of damage appear only after a long period following the start of feeding. Afflicted animals experience a drop in milk production, decreased appetite, pronounced lethargy, and paralysis of the hind limbs. The course of the poisoning is chronic and often ends in the death of the livestock.