In this article
Stringhalt in Horses by a Vet – 2025 Guide to Equine Reflex Hypertonia & Plant-Related Causes 🐎🦵🌿
By Dr Duncan Houston, BVSc
What Is Stringhalt (Equine Reflex Hypertonia)?
Stringhalt, or Equine Reflex Hypertonia, is a neuromuscular condition marked by exaggerated, jerky movements of one or both hind limbs. Affected horses often lift their hind legs abnormally high while walking—resembling a marionette being yanked by a string. 🧵
How to Recognize Stringhalt in 2025
- Most obvious at the walk; may improve at trot or canter
- More noticeable when backing up, turning, or starting to walk after rest
- Hind leg may jerk up suddenly before placing it down
- Signs can be sporadic or seasonal—often less visible in warm weather
Types of Stringhalt 🧬
1. Pasture-Associated Stringhalt (Plant-Linked) 🌾
- Occurs when horses graze on toxic plants, especially in late summer or autumn
- Also called Australian stringhalt
- Common in Australia, New Zealand—rare in the US, but does occur
- Appears suddenly and may affect multiple horses in the same region
Known Toxic Plants 🍃
- Hypochaeris radicata (False Dandelion) – Found in the US, Europe, and Australia
- Lathyrus spp. (Sweet Pea Plant) – Found in the US, associated with neuromuscular issues
2. Idiopathic Stringhalt (Cause Unknown) ❓
- Chronic and potentially progressive form of stringhalt
- Cause remains undetermined
- Not associated with pasture conditions or toxins
- Can affect one or both hind limbs and often persists long-term
Diagnosis of Stringhalt 🧠
- Based on clinical signs and movement evaluation
- No specific diagnostic test—rule out other neurological or musculoskeletal issues
- Evaluate pasture conditions and look for known toxic weeds
Treatment Options 💊
For Plant-Associated Stringhalt 🌿
- Immediate removal from suspect pasture is the first step
- Improvement may be seen within weeks or months
- No further treatment may be required
For Idiopathic or Chronic Stringhalt 🧬
- Surgical Option: Lateral digital extensor tenectomy may improve movement
- Thiamine (Vitamin B1) – May support nerve health
- Phenytoin (anticonvulsant) – Sometimes used to decrease reflex hypertonia
- Not all horses respond to medical or surgical treatment
Can a Horse with Stringhalt Live Normally? 🐴❤️
- Yes, many horses with mild stringhalt lead fulfilling lives
- Performance limitations depend on severity and type of work expected
- Horses with moderate cases may still be suitable for trail riding or light work
Preventing Plant-Associated Stringhalt 🌱
- Inspect pastures regularly for false dandelions or sweet pea plants
- Avoid overgrazing and rotate pastures
- Provide supplemental forage during drought or late-season grazing
Case Example: Pasture Stringhalt in a Show Gelding
- 8-year-old Quarter Horse began jerky movement after a dry summer
- Pasture inspection revealed large amounts of false dandelion
- Horse was removed from pasture and placed on stall rest
- Signs improved over 3 weeks with B1 supplementation
- Returned to light work within 2 months
FAQs About Stringhalt in Horses 🧠
Q: Is stringhalt painful for my horse?
A: Typically, no. It is more of a movement abnormality than a source of pain, unless injury occurs due to jerky motion.
Q: Will it affect both hind legs?
A: Sometimes. It may affect one or both limbs depending on the type and severity.
Q: Is stringhalt contagious?
A: No. It's not a contagious disease, although multiple horses in a toxic pasture may be affected.
Conclusion
Stringhalt is a distinctive, often startling movement abnormality—but it’s not necessarily a sentence for retirement or loss of function. In many cases, pasture changes, supportive therapy, and time lead to improvement. For more severe or idiopathic cases, surgical or medical treatment may be needed. Early diagnosis and pasture inspection are key to managing this condition in 2025.
Concerned about strange hind limb motion or jerky gaits? Visit AskAVet.com or download our app 📱 to consult directly with Dr Duncan Houston. Let's work together to identify and manage your horse's movement needs. 🩺🐴
