English Oak (Acorns and Buds)
Quercus robur
Horse
Severe
Any suspected ingestion is an immediate veterinary emergency. Massive and repeated consumption of green acorns (several kilograms over a few days) or young 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, gastric protectants, activated charcoal if recent ingestion).
- Time to signs
- 24 to 72 hours
- Prognosis
- Guarded. Can be fatal if the kidneys are too damaged (acute renal failure).
- Call the veterinarian.
- Remove the animal from the area.
- Administer paraffin oil and mucilages to coat the intestines.
- Provide renal support with intravenous fluids.
Its ID card
- Height
- Jusqu'à 40 m
- Flowering
- April to May
- Toxic parts
- Green acorns (ripe brown ones are less dangerous but should be avoided), young leaves in spring, buds.
- Toxin
- Hydrolyzable tannins (gallic acid, tannic acid)
- Habitat
- Forests, hedgerows, pastures, parks.
- Soil indicator
- Tolerates almost all soils.
- Regions
- All of Europe
- In hay
- Not reported
- Palatability
- Very palatable! Some horses develop a real addiction to acorns (sweet/bitter effect) and actively seek them out.
When the risk rises
September to November (acorns), March-April (buds).
Spotting it in the field
None. — smell : faint, woody odor, more pronounced when leaves or acorns decompose.
- Majestic tree.
- Characteristic lobed leaves.
- Fruits (acorns) in a cupule.
Signs to watch for
Both acute and chronic (cumulative) toxicity
Dose : Several kilograms of green acorns or young leaves over a few days for an adult horse.
- Severe constipation followed by black/bloody diarrhea
- Blood in the urine (hematuria)
- Dull colic and loss of appetite
- Edema under the belly and in the limbs
- Profound depression (uremia)
Who is affected
Other species : Toxic to cattle and sheep. Pigs, however, digest them very well.
In pregnant mares : can cause abortion due to renal failure.
Getting rid of it
Method : Pruning of low branches, fencing off high-risk areas.
- Keep horses away from areas with oak trees during critical periods (autumn for acorns, spring for buds).
- Provide sufficient good-quality hay to reduce appetite for acorns.
- Monitor horses closely, especially those prone to eating acorns.
Frequently asked questions
Can Equio identify English Oak (Acorns and Buds) from a photo?
It can help organize visual clues, but plant identification must remain cautious when horse health is at stake.
Is English Oak (Acorns and Buds) 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.