Periwinkle (Greater and Lesser)
Vinca major / Vinca minor
Horse
Moderate
Get veterinary advice the same day and remove access. A significant consumption (several handfuls of vines and leaves).
Equio informs, it does not diagnose. When in doubt, call your vet.
What to do now
- Antidote
- No specific antidote. Symptomatic and supportive treatment (IV fluids, cardiovascular monitoring).
- Time to signs
- A few hours to 24 hours.
- Prognosis
- Good. Mortality is rare in large herbivores; symptoms regress with elimination of the toxin.
- Call a veterinarian if the horse shows signs of severe weakness (low blood pressure).
- Absolute rest.
- Rehydration.
Its ID card
- Height
- 0.2 m – 0.6 m
- Flowering
- March to June.
- Toxic parts
- Entire plant (stems, leaves, flowers).
- Toxin
- Indole alkaloids (Vincamine, vincristine).
- Habitat
- Clear undergrowth, shaded embankments, old cemeteries, hedges, parks.
- Soil indicator
- Cool, forest soils, rich in humus, shaded.
- Regions
- Entire Europe
- In hay
- Yes — stays toxic once dried
- Palatability
- Low (tough and bitter leaves). Often browsed out of boredom in winter when it is the only green plant on the ground.
When the risk rises
Winter and early spring.
Spotting it in the field
English Ivy (lobed leaves, no large blue flowers). — smell : odorless.
- Creeping plant forming a dense carpet.
- Persistent, leathery, dark green, shiny, oval, and opposite leaves.
- Very recognizable solitary flowers with 5 asymmetrical petals (propeller-shaped) of a characteristic blue-violet ('periwinkle blue').
Signs to watch for
Acute toxicity.
Dose : Difficult to quantify precisely, depends on alkaloid concentration and horse size. Significant consumption of fresh plant is required.
- Sudden drop in blood pressure (hypotension)
- Extreme weakness, staggering or recumbent horse
- Spasmodic colic and diarrhea
- Slowing of heart rate
- Muscle tremors
Who is affected
Other species : Toxic to dogs and cats (digestive and cardiac disorders).
In pregnant mares : can cause abortion due to a sudden drop in blood pressure (fetal hypoxia).
Getting rid of it
Method : Pull the plant manually wearing gloves to avoid skin contact. Dispose of waste appropriately (composting away from animals, incineration).
- Identify and remove periwinkle from paddocks and grazing areas.
- Closely monitor horses during rides in forests or areas where periwinkle is present.
- Avoid overgrazing, which can encourage horses to consume less palatable plants.
Frequently asked questions
Can Equio identify Periwinkle (Greater and Lesser) from a photo?
It can help organize visual clues, but plant identification must remain cautious when horse health is at stake.
Is Periwinkle (Greater and Lesser) dangerous in hay?
This entry flags hay vigilance. Isolate suspicious forage and ask for professional advice if exposure is possible.
This page is informational. If ingestion is likely, if signs appear, or if the horse is fragile, contact a veterinarian immediately.