Hairy Vetch Toxicosis in Horses
Key takeaways
Hairy vetch toxicosis is a rare and life-threatening condition in horses caused by the ingestion of the hairy vetch (Vicia villosa) plant.
- The toxicosis is linked to systemic granulomatous disease (SGD), a highly lethal inflammatory condition
- The specific toxin responsible is unknown
- Common symptoms of toxicosis include weight loss, skin irritation, peeling of skin around the nose, enlarged lymph nodes, and swelling of the lower limbs
- Diagnosis is based on history of exposure, physical examination, and exclusion of other potential conditions
- Treatment options are limited as no specific antidote or treatment is currently available
- The severity of the condition and the limited treatment options make prevention crucial -Removal of hairy vetch plants from pasture and feed is the only way to ensure the animal's well-being
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A closer look: Hairy Vetch Toxicosis in Horses
Hairy vetch toxicosis is a rare condition in horses but carries a high mortality rate; as such must be treated as an emergency.
Due to the highly lethal nature of the condition and the limited treatment options, prevention is the only way to ensure the animal's safety. The best prevention strategies include removing hairy vetch plants from pastures, and providing adequate amounts of alternative feed sources.
Risk factors
The ingestion of hairy vetch plants is linked to systemic granulomatous disease (SGD), a rare, serious, and highly fatal condition that causes inflammation of the skin and internal organs.
Possible causes
Hairy vetch toxicosis is caused by the ingestion of the Vicia villosa plant, an annual climbing legume present throughout the United States, most of Canada, Europe, and western Asia.
The specific toxic responsible for the poisoning is currently unknown. Vicia villosa is known to contain considerable amounts of nitrogen and cyanogenic glycosides, which may contribute to the toxicosis.
Main symptoms
Testing and diagnosis
Diagnosis of hairy vetch toxicosis is based on history of exposure and symptoms; standard diagnostic tools include:
- Physical examination
- Blood tests
- Skin biopsy
- Ultrasound of internal organs
Steps to Recovery
Currently, there is no antidote or specific treatment for hairy vetch toxicosis. Once diagnosed, treatment focuses on symptomatic and supportive care.
Horses diagnosed with SGD are generally treated with corticosteroids (oral prednisolone), however treatment is typically ineffective.
Prognosis for hairy vetch toxicosis is poor due to the lack of treatment options.
The majority of horses diagnosed with SGD are unable to recover, and die as a result of progressive debilitation. Most horses are euthanized early on in the disease due to the poor prognosis.
Prevention
Hairy vetch toxicosis is not contagious.
Toxicosis is entirely preventable by ensuring that horses do not ingest Vicia villosa plants. Prevention strategies include:
- Regular pasture inspections
- Removal of hairy vetch plants
- Inspection of hay prior to feeding
- Research of potential toxic plants before planting new seeds in farm or pasture
- Providing adequate amounts of alternative feed sources
Is Hairy Vetch Toxicosis in Horses common?
Hairy vetch toxicosis is a rare condition in horses.
The majority of cases occur during the spring months.
Typical Treatment
- Supportive care
- Corticosteroids
