Sycamore Maple
Acer pseudoplatanus
Horse
Critical
Any suspected ingestion is an immediate veterinary emergency. Variable (depends on the tree and season), from a few dozen seeds to a few hundred seedlings.
Equio informs, it does not diagnose. When in doubt, call your vet.
What to do now
- Antidote
- No specific antidote. Intensive symptomatic and supportive treatment.
- Time to signs
- A few hours to 2-3 days
- Prognosis
- Very poor. Mortality rate of around 70 to 75%.
- Absolute emergency.
- Do not move the horse.
- Cover the horse.
- Massive IV fluid therapy by the veterinarian to drain myoglobin and protect the kidneys.
Its ID card
- Height
- 15 m – 35 m
- Flowering
- April to May
- Toxic parts
- Seeds (samaras) falling in autumn, and young seedlings (2-leaf shoots) in spring.
- Toxin
- Hypoglycin A (HGA)
- Habitat
- Woods, forest edges, hedgerows, parks.
- Soil indicator
- Tolerates many soils, prefers cool soils.
- Regions
- Europe, Western Asia
- In hay
- Not reported
- Palatability
- Medium. Ingested by mistake in short grass or due to lack of forage.
When the risk rises
October-November and March-May.
Spotting it in the field
Norway Maple (samaras very spread out, slightly toxic), Field Maple. — smell : slight, pleasant smell of leaves, but no distinctive smell from toxic seeds or seedlings.
- Palmate leaves with 5 lobes.
- Seeds grouped in samaras (helicopters) forming an acute angle (like a circumflex accent).
- Grayish bark, smooth on young trees, becoming scaly and peeling off in plates on mature trees.
Signs to watch for
Acute toxicity.
Dose : Variable, but a few hundred seeds or seedlings can be sufficient for a horse.
- Very dark urine (red/brown like coffee grounds)
- Extreme stiffness, refusal to move
- Recumbent horse unable to rise
- Sweating and tremors
- Congestion of mucous membranes
Who is affected
Other species : A few cases in ruminants, but equids are by far the most sensitive.
In pregnant mares : major risk of mare death.
Getting rid of it
Method : Pull up young seedlings before they are ingested. Seeds can be collected and disposed of.
- Keep horses away from at-risk areas during critical periods (autumn and spring).
- Ensure adequate feeding to prevent horses from grazing short grass and young shoots.
- Identify and, if possible, remove at-risk trees near pastures.
Frequently asked questions
Can Equio identify Sycamore Maple from a photo?
It can help organize visual clues, but plant identification must remain cautious when horse health is at stake.
Is Sycamore Maple dangerous in hay?
Hay risk is not always reported for this entry, but suspicious forage should still be isolated until checked.
This page is informational. If ingestion is likely, if signs appear, or if the horse is fragile, contact a veterinarian immediately.