Fixing Underslung Heels: A Farrier’s Guide to Proper Trim and Balance

Under-run heels, also known as underslung heels or collapsed heels in horses, are among the most prevalent hoof capsule distortions observed in modern equine hoof care.
When the heel base collapses forward, the hoof-pastern axis becomes misaligned, shifting the horse’s toe-to-heel ratio and increasing strain on the deep digital flexor tendon (DDFT) and the navicular apparatus (Hunt, 2012).

Research from the Royal Veterinary College (2023) found that heel collapse often reduces digital cushion support and increases risk of horse lameness by up to 20 percent. Integrating corrective trimming for horses, hoof balance correction, and heel structure improvement ensures proper alignment, stronger hoof horn, and consistent heel-first landings.

This guide combines real-world farrier trimming techniques, hoof biomechanics, and corrective farriery practices to offer practical solutions for achieving sustainable heel restoration trimming.

 

Introduction

Across performance disciplines, horses frequently develop under-run heels due to improper shoeing, soft footing, and inconsistent hoof trimming schedules. The heel bulb distortion caused by hoof capsule distortion alters load distribution and affects the horse’s entire equine hoof alignment therapy process.

Improper farrier tools and equipment, lack of hoof mapping, or misjudged hoof angle correction can lead to long-term hoof conformation correction challenges. This blog explains how to identify collapsed heels, perform hoof correction trimming, apply corrective shoeing techniques, and maintain heel height adjustment through equine podiatry best practices.

The outcome of correct hoof rehabilitation is improved heel balance in horses, reduced strain on the tendons, and a sounder, more efficient stride.

 

Understanding Under-Run (Underslung) Heels

An under-run heel or crushed heel occurs when the heel wall grows forward rather than downward, flattening the hoof’s natural angle. This results in hoof capsule realignment issues, improper hoof load redistribution, and lateral–medial heel imbalance (O’Grady, 2018).

The hoof-pastern axis becomes broken-back, shifting weight toward the toe and forcing the digital cushion and frog health to deteriorate. Radiographic studies (RVC, 2023) indicate that a heel angle below 35° increases heel pain and limits palmar angle adjustment.
Externally, affected horses display a flattened hoof, narrow frog, and low heel conformation; internally, there is reduced elasticity within the hoof horn.

Skilled professionals diagnose heel collapse in horses through hoof gauge measurement, evaluating hoof wall balance, and inspecting for toe-first landings. These evaluations allow targeted hoof distortion repair before permanent damage occurs.

 

Causes of Heel Collapse and Imbalance

Multiple factors contribute to heel collapse and hoof distortion repair challenges. Genetic predisposition to low heel conformation and long toes increases the likelihood of heel base stabilization failure (Hunt, 2012). Infrequent horse hoof trimming or extended shoeing intervals exceeding six weeks allow toe leverage reduction to fall out of balance, encouraging underrun heel correction issues.

Environmental stressors such as wet-dry cycles soften the hoof horn, while poor hoof nutrition and care weaken hoof horn quality. Nutritional analysis has shown that consistent biotin for hoof growth supplementation (15–20 mg/day) improves hoof wall strength and hoof growth support (KER, 2024).

Excessive concussion on hard terrain without adequate bar shoes for horses or wedge pads for horses also accelerates heel collapse. These pads or heel support pads can help mitigate excessive impact by promoting proper heel height and hoof-pastern alignment during rehabilitation (Morrison, 2012).

 

Step-by-Step Trimming Techniques for Correction

1. Assessment and Mapping

Correction begins with comprehensive hoof mapping and identifying medial–lateral balance. The hoof should be cleaned and trimmed to the functional sole plane to assess hoof alignment and hoof angle correction (AAEP, 2024).

Using hoof trimming tools, hoof gauge measurements, and photographic documentation allows for accurate comparisons over multiple farrier trimming schedules.

2. Reducing Toe Leverage

The first trimming goal is toe leverage reduction. Excessive toe length pulls the heel forward, intensifying hoof capsule distortion. Carefully shorten the toe with farrier hoof care tools like nippers and a rasp to promote proper toe-to-heel ratio correction.

Each trim should aim to gradually restore the hoof balance correction while maintaining the natural hoof biomechanics (Hunt, 2012). The process must be repeated every 4–6 weeks to stabilize heel growth and ensure progressive heel conformation correction.

3. Re-Establishing Heel Orientation

Trim the heels to the functional sole plane, ensuring they grow upright without lowering excessively. Equalizing medial-lateral balance maintains heel base stabilization, while maintaining a consistent palmar angle adjustment (O’Grady, 2018).

A straight-edge or digital hoof gauge ensures that heel height adjustment is symmetrical, improving horse hoof alignment and comfort.

4. Supportive Shoeing or Transitional Protection

In moderate or advanced cases, corrective shoeing for heel collapse is necessary. Options include bar shoes, egg-bar shoes, and wedge pads for horses to correct heel bulb displacement and promote heel-first landing in horses (Morrison, 2012).\

For barefoot horses, hoof boots or temporary heel support pads protect sensitive heels during hoof rehabilitation and heel remodeling. Proper farrier corrective trimming paired with these supports helps restore a positive hoof-pastern axis.

5. Documentation and Evaluation

Record all hoof angle measurements, heel height changes, and hoof alignment restoration progress after each cycle. Track signs of improvement—such as heel-first landings, better hoof load redistribution, and expanded frog health—to validate correction (RVC, 2023).

 

Essential Tools and Techniques for Heel Restoration

Successful heel restoration trimming relies on ergonomic, precision farrier tools for horses and reliable equine farrier supplies.

A sharpened hoof knife defines the frog health zone, while durable hoof trimming tools and rasps ensure smooth hoof wall balance and even hoof capsule realignment (Hunt, 2012; Morrison, 2012).

Digital hoof gauges and protractors allow accurate monitoring of hoof angle correction and heel balance in horses (AAEP, 2024).

When applying bar shoes for heel support or wedge pads, select materials that combine durability and shock absorption, promoting hoof biomechanics that mimic natural ground contact (RVC, 2023).

(See Figure 2 for proper rasp and hoof gauge alignment during heel restoration trimming.)

 

Preventive Hoof Care and Maintenance Schedule

Sustained success in equine hoof rehabilitation depends on consistent trimming and hoof maintenance schedules. Horses should be trimmed every 4–6 weeks to maintain correct toe-to-heel ratio and hoof-pastern axis alignment (AAEP, 2024).

Regular, controlled movement on solid yet elastic ground encourages heel-first landing and enhances digital cushion support (Morrison, 2012). Stable management practices—such as keeping bedding dry—prevent contracted heels and hoof capsule distortion (Hunt, 2012).

Balanced nutrition with biotin for hoof growth and essential amino acids reinforces hoof horn quality, while medial-lateral balance monitoring ensures continued heel structure improvement (KER, 2024). Periodic radiographs confirm the palmar angle adjustment and detect early signs of relapse (RVC, 2023).

 

Real-World Application Example

In a practical rehabilitation case, a mature sport horse exhibited collapsed heels, crushed hoof capsules, and recurring heel pain. Radiographs revealed a –2° palmar angle with significant hoof load redistribution toward the toe.

Over four corrective trimming cycles, spaced five weeks apart, the farrier applied step-by-step hoof trimming techniques for heel correction and used bar shoes for two cycles to maintain heel stability.

Within six months, the horse’s heel height improved by 6°, heel-first landings resumed, and hoof horn quality increased (AAEP, 2024). This case demonstrates the effectiveness of progressive farrier-guided heel correction and equine hoof soundness restoration through consistent corrective farriery techniques.

 

Conclusion

Reversing under-run heels requires a balance of biomechanics, nutrition, and hoof correction tools. Correcting heel collapse through controlled toe leverage reduction, heel base stabilization, and palmar angle adjustment re-establishes healthy hoof-pastern alignment (O’Grady, 2018).
With systematic farrier trimming techniques, heel restoration trimming, and disciplined hoof nutrition and care, farriers can achieve lasting hoof balance correction and horse lameness prevention (Morrison, 2012; AAEP, 2024).

Ultimately, a successful equine hoof rehabilitation plan depends on precision, patience, and collaboration between farrier, veterinarian, and horse owner.

 

Frequently Asked Questions(FAQs)

Q1: What causes under-run or underslung heels in horses?

A: They develop due to excessive toe length, weak digital cushion support, irregular trimming cycles, and prolonged exposure to soft or wet footing (Morrison, 2012).

Q2: How can trimming correct heel collapse?

A: Through consistent corrective trimming for horses, farriers reduce toe leverage, rebalance the hoof-pastern axis, and encourage natural heel growth support (O’Grady, 2018).

Q3: How often should a horse with under-run heels be trimmed?

A: Every 4–6 weeks to maintain heel alignment, avoid hoof capsule distortion, and preserve hoof balance correction (AAEP, 2024).

 

Call to Action

Farriers and hoof-care professionals should document trimming results, monitor gait transitions, and refine heel correction trimming methods over time.
By adhering to these corrective shoeing horses protocols and using proper farrier trimming tools, practitioners can promote hoof conformation correction and maintain consistent equine hoof care standards (AAEP, 2024).

 

References

• American Association of Equine Practitioners (AAEP). (2024). Hoof-pastern axis alignment and lameness prevention. AAEP Proceedings.
• Hunt, R. J. (2012). Farriery for the hoof with low or underrun heels. Veterinary Clinics of North America: Equine Practice, 28(1), 49–63.
• Kentucky Equine Research (KER). (2024). Biotin and hoof horn strength: Nutritional interventions for hoof integrity. KER Technical Bulletin.
• Morrison, S. (2012). Hoof capsule distortions and functional consequences. CABI Publishing.
• O’Grady, S. E. (2018). Principles for managing low and underrun heels. CABI Review Series in Farriery.
• Royal Veterinary College (RVC). (2023). Digital cushion function in heel collapse: Radiographic and biomechanical analysis. RVC Equine Research Department.

You may also like this  Fixing Underslung Heels: A Farrier’s Guide to Proper Trim and Balance