Vicia sativa (vetch). A member of the plant family PAPILIONACEAE. Slightly
hairy, stout annual plant, with green leaflets ending in tendrils. Purple flowers,
solitary or in pairs, long erect pods containing 4-12 smooth, round seeds.
Animals most affected
Pigs, horses, cattle, sheep, goats, poultry.
Ingestion of plant fodder or seeds.
Contains a cyanogenetic glycoside (vicianine), amino acids and toxic heterosides.
Vicianine is present only in the seeds (the plant can be damaging to health once
the pods are formed).
Toxic doses unknown but large animals need to ingest considerable amounts, 10-20%
of the diet, for prolonged periods of time (several weeks) before symptoms present.
Diarrhoea, colic, jaundice.
Paraplegia, pharyngeal paralysis.
Muscular weakness and rapid death following ingestion of the seeds.
No antidote. Symptomatic care only:
prevent continuous or prolonged ingestion of the plant material;
mix vetch hay with other fodder.
Check seeds to be given as feed to birds and poultry.
At a farm of Shetland ponies, seven animals died and an eighth presented with the
following clinical signs: weakness, apathy, a drooping head and difficulty in swallowing.
Also noted were a paralysis (more or less marked) of the legs and intermittent collapse
to the ground with paddling movements. The ponies had been given hay made exclusively
from cut vetch. However, the plants had been harvested too late, after flowering,
and the feedstuff contained only seeds and dried seed pods.