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.


[affected.gif] Animals most affected
Pigs, horses, cattle, sheep, goats, poultry.


[etiology.gif] Etiology
Ingestion of plant fodder or seeds.


[toxic.gif] Toxicity
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.


[clinical.gif] Clinical features
Gastrointestinal
Diarrhoea, colic, jaundice.

Neurological
Somnolence:
Paraplegia, pharyngeal paralysis.

Dermal
Photosensitization.

In poultry
Muscular weakness and rapid death following ingestion of the seeds.

In horses
Occasionally haemoglobinuria.


[lesions.gif] Lesions
Non-specific:


[treatm~1.gif] Treatment
No antidote. Symptomatic care only:

Check seeds to be given as feed to birds and poultry.


[case.gif] Case summaries
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.