🧠 Vet Insight 2025: Understanding Equine Stringhalt (Reflex Hypertonia) and How to Help 🐎

Have you noticed your horse suddenly lifting one of its hind legs high in a jerky motion, almost like a puppet pulled by a string? This unusual gait is likely caused by a condition known as stringhalt, or Equine Reflex Hypertonia. While it may appear dramatic, not all cases are serious—and many horses continue to live comfortable lives with proper management. In this 2025 guide, Dr Duncan Houston breaks down everything you need to know about stringhalt, including its causes, symptoms, and treatment options. 🧠🐴

🔍 What Is Stringhalt?

Stringhalt is a neuromuscular disorder that causes abnormal gait in horses—specifically exaggerated flexion of one or both hind limbs. Affected horses will:

• 🦶 Hold a hind leg up in an unnatural, high-stepping motion
• 🚶‍♂️ Show jerky, hesitant steps—especially noticeable at the walk
• 🔁 Display more prominent symptoms when backing up or turning

The condition often affects one hind leg, but in some cases, both can be involved. The unusual movement is more visible at slow gaits and can improve during trotting or cantering. 🧠

🧬 Types of Stringhalt

1. 🤷‍♂️ Idiopathic Stringhalt

Also called “Australian stringhalt,” this type has no known cause and may be progressive. It’s the most concerning variant due to its potential to worsen over time and lead to long-term impairment.

2. 🌱 Pasture-Associated (Plant-Associated) Stringhalt

Also known as PSH, this form is linked to toxic plants found in poor-quality or drought-stressed pastures. It is often seen during late summer or early autumn, particularly when horses begin eating forage they would normally avoid due to limited availability.

🧠 Good news: PSH usually resolves once the horse is removed from the toxic pasture. ✅

🌿 Plants Linked to Stringhalt

While pasture-associated stringhalt is rare in the United States, it can still occur under specific conditions. Plants linked to stringhalt include:

• 🌼 Hypochaeris radicata (False Dandelion) – Often confused with real dandelions
• 🌸 Lathyrus spp. (Sweet Pea) – Can be found in some U.S. regions

These plants tend to be consumed when grazing conditions are poor due to drought, overgrazing, or mismanagement. Even horses on well-managed pastures may nibble on toxic weeds out of curiosity or boredom. 🌱

🧪 Diagnosing Stringhalt

If your horse is showing high-stepping movements, especially in a hind limb, your vet may perform:

• 👀 Visual gait evaluation (walk, turn, back up)
• 🧠 Neurological examination
• 📈 Observation during different seasons or weather conditions

Bloodwork and imaging may be used to rule out other causes of abnormal hind limb movement such as trauma, neurological diseases, or arthritis. 🔬

💊 Treatment Options

1. 🌱 Remove the Toxin (for PSH)

• Immediately remove horses from the affected pasture
• Check for and remove false dandelion or sweet pea plants
• Supplement with clean hay and forage during recovery

2. 💊 Medical Management

For idiopathic cases or horses needing additional support:

• 💉 Thiamine (Vitamin B1) – Supports nerve function
• 🧠 Phenytoin – An anticonvulsant used in some cases

3. 🔧 Surgical Treatment

In chronic or severe idiopathic cases, a surgical procedure known as lateral digital extensor tenectomy may be considered. This involves:

• ✂️ Cutting part of the affected tendon/muscle group
• 📉 Reducing the exaggerated flexion

Note: Not all horses respond to surgery, and recovery depends on age, severity, and overall health. 🧬

🐴 Can Horses with Stringhalt Still Work?

Stringhalt is considered an unsoundness, but it doesn’t always mean the end of your horse’s riding career. Many horses with mild or intermittent symptoms can still:

• 🏞️ Enjoy trail riding
• 🎠 Participate in light flat work
• 💙 Live pain-free with proper care and management

Symptoms may lessen in warm weather or with regular turnout. However, horses with severe cases may be unsuitable for competition or heavy work. ❄️

📲 Ask A Vet: Real-Time Support for Neurological Issues

If your horse is showing stringhalt symptoms, the Ask A Vet app connects you with experts like Dr Duncan Houston for fast guidance, case reviews, and treatment planning. 🧠📱

• 📸 Share videos of your horse’s gait
• 🧪 Upload past test results or treatment history
• 💬 Get veterinary insights without the wait

Download the Ask A Vet app today to start a personalized plan for your horse’s movement health. 🐴

🏁 Final Thoughts: Don’t Fear the String

Stringhalt may look strange, but it’s not always harmful. By understanding the difference between idiopathic and pasture-associated stringhalt, you can make informed care decisions and support your horse’s comfort and quality of life. ✅

Always monitor pasture quality, avoid known toxic weeds, and keep your vet involved if signs appear. With early intervention, many horses show improvement—and some recover fully. 🌿

🐾 Need expert help? Visit AskAVet.com or download the Ask A Vet app to connect with Dr Duncan Houston and ensure your horse stays sound, safe, and supported. 🐎💙