Laminitis is one of the most painful and debilitating conditions a horse can face — and one of the most common calls an equine vet will receive. For horse owners, it’s a frightening diagnosis. For practitioners, it’s both a clinical challenge and an opportunity: to dig deeper, identify root causes, and deliver faster, more confident care. 

Understanding what drives laminitis — not just how to manage it once it’s present — is where modern diagnostics are making a real difference. Point-of-care testing is changing what’s possible in the field and in the clinic, giving equine vets the tools to do more for their patients without sending samples off to a reference lab and waiting. 

What Is Laminitis in Horses? 

Laminitis is inflammation of the laminae — the sensitive tissue that connects the coffin bone (pedal bone) to the inner hoof wall. When this tissue becomes damaged or inflamed, the structural integrity of the hoof is compromised. In severe or chronic cases, the coffin bone can rotate or sink, causing permanent damage and significantly impacting a horse’s quality of life. 

The condition can affect any horse or pony of any age or breed, though certain populations are at significantly higher risk — particularly older horses, easy keepers, and animals with underlying endocrine disorders. Laminitis can present acutely, with sudden severe lameness, or develop more gradually in horses with chronic, unmanaged systemic disease.  

What’s critical to understand is that laminitis is frequently a symptom, not the root problem. Treating the hoof without addressing the underlying cause puts horses at high risk for recurrence — and more serious episodes over time. The American College of Veterinary Internal Medicine (ACVIM) and the Equine Endocrinology Group both emphasize endocrine evaluation as a core component of any laminitis workup. 

Recognizing Laminitis: Clinical Signs to Watch For 

Early recognition is essential. The sooner laminitis is identified and the underlying cause addressed, the better the prognosis for the horse. Key clinical signs include: 

• Characteristic laminitic stance: Weight shifted back onto the heels to relieve pressure on the toes 

• Increased digital pulse: Bounding or easily palpable pulse in the digital arteries 

• Heat in the hooves: Warmth detectable at the coronary band or hoof wall 

• Reluctance or refusal to move: Stiff, stilted gait or outright unwillingness to bear weight 

• Rocking or shifting weight: Especially in horses with bilateral forelimb involvement 

• Hoof wall changes: In chronic cases, growth rings (founder rings), divergent rings, or a dished hoof wall 

The Obel grading scale remains a useful clinical tool for characterizing severity, from Grade I (mild, intermittent weight shifting) to Grade IV (refusal to move, extreme pain). Regardless of grade, any suspected laminitis episode warrants prompt investigation — including a hard look at what may be driving it systemically. 

The Underlying Causes Vets Can’t Afford to Miss 

When a horse presents with laminitis, the hoof is where you see the problem — but the origin is often elsewhere. Two endocrine conditions are among the most significant drivers of laminitis in horses: insulin dysregulation (ID) and pituitary pars intermedia dysfunction (PPID). 

Insulin Dysregulation 

Insulin dysregulation is now recognized as one of the leading causes of laminitis in horses and ponies. Abnormally elevated insulin levels — whether from diet, obesity, or an underlying metabolic disorder — directly trigger laminitic episodes. Horses with a history of laminitis, easy-keeper body condition, or cresty necks should be evaluated for ID as a matter of course. 

Current options for detecting risk of hyperinsulinemia-associated laminitis (HAL) include resting insulin measurement and the oral sugar test (OST), which provides a dynamic picture of insulin response and is recommended by the Equine Endocrinology Group as the preferred screening method for horses and ponies on managed diets. The OST requires post-challenge insulin measurement at 60–90 minutes, making fast, in-clinic turnaround especially valuable. 

PPID (Equine Cushing’s Disease) 

Pituitary pars intermedia dysfunction is the most common endocrine disorder in older horses. PPID is caused by degeneration of dopaminergic neurons in the hypothalamus, which leads to overproduction of ACTH and other pituitary hormones. Elevated ACTH is associated with elevated cortisol synthesis, and increased laminitis risk — along with a host of other clinical signs including hypertrichosis, muscle atrophy, weight loss, polydipsia, and recurrent infections. 

The prevalence of PPID is significant: roughly 1 in 5 horses over the age of 15 is affected, with prevalence rising to approximately 30% in horses over 30. And while hypertrichosis (the classic long, curly coat that fails to shed) is the most recognizable sign, many horses present with subtler symptoms — including laminitis — well before the haircoat changes appear. 

It’s also worth noting the seasonal ACTH rise: in the late summer and autumn months (typically August through October in the Northern Hemisphere), horses naturally experience an elevation in ACTH levels. In PPID-affected horses, this seasonal rise is exaggerated and directly associated with increased laminitis risk. The Equine Endocrinology Group’s PPID guidelines recommend adjusted seasonal reference ranges during this window and advise extra vigilance for laminitis episodes in the fall. Proactively screening older horses ahead of this period — and communicating that recommendation to horse owners — is one of the highest-value things an equine practitioner can do. 

For any horse presenting with laminitis, especially in middle age or older, ruling out PPID and insulin dysregulation isn’t optional. It’s foundational to good care. 

Traditional Diagnostic Methods — and Their Limitations 

Diagnosing endocrine-driven laminitis has historically meant sending samples to a reference laboratory for ACTH or insulin measurement. Current standard-of-care options include: 

• Baseline endogenous ACTH (eACTH) measurement for PPID diagnosis in horses with overt clinical signs 

• TRH stimulation testing, in which thyrotropin-releasing hormone is administered intravenously and ACTH is measured at prior to injection and 10 minutes post-injection — the recommended method for detecting early-stage PPID before clinical signs are pronounced 

• Resting insulin and the oral sugar test (OST) for evaluating insulin dysregulation 

 

These are well-validated approaches, and the Equine Endocrinology Group’s published guidelines remain the clinical reference standard for when and how to use them. But each of these tests — particularly eACTH measurement — comes with real-world logistical constraints that reference lab workflows struggle to address. 

Endogenous ACTH is extremely labile. The hormone degrades rapidly at room temperature — studies show that samples can lose more than 50% of their eACTH concentration within 24 hours of collection, with meaningful degradation beginning as early as two to four hours. Strict cold-chain protocols are required from the moment of collection through arrival at the lab. Any deviation — a warm shipping environment, a handling delay, a delayed centrifugation step — can yield results that don’t reflect the horse’s true hormone levels. Erroneous values mean diagnostic uncertainty, which means delayed treatment. 

Turnaround time adds another layer of friction. Reference lab results typically take 24 hours or more — not counting shipping time and weekend closures. That means a second conversation with the horse owner, a callback, and a gap between testing and treatment initiation. For a horse already in pain, that delay matters. 

Insulin testing faces similar challenges. The OST in particular requires a timed post-challenge draw, making fast, reliable on-site measurement significantly more practical than a reference lab send-out. 

These aren’t failures of the reference lab model — they’re inherent constraints of the workflow. But they are constraints that newer technology is now designed to address. 

How The TRUFORMA® Diagnostic Platform Is Changing the Diagnostic Process 

For equine practitioners ready to bring endocrine diagnostics in-house, the results speak for themselves — and for the horse owner who no longer has to wait. 

The TRUFORMA® platform from Zomedica is built on bulk acoustic wave (BAW) technology — a non-optical, fluorescence-free detection system originally developed for use in telecommunications and aerospace. It’s available at the point of care in veterinary clinics and in the field, and it’s purpose-built to address the sample handling and turnaround limitations of reference lab workflows. Learn more at zomedica.com/truforma → 

TRUFORMA eACTH Assay for Equine Plasma 

Thanks to the TRUFORMA platform, sample handling challenges associated with shipping are substantially reduced — meaning results that more accurately reflect the horse’s actual hormone status. Performance data supports its use with confidence. The assay demonstrated high correlation with the Siemens IMMULITE reference lab assay (R=0.96), with minimal overall bias. The dynamic range of 5–1,250 pg/mL covers both the low end relevant to nuanced clinical decisions and the high concentrations associated with pronounced PPID — without dilution or additional processing steps. Results are available in under 20 minutes, compared to 60+ minutes for the reference lab workflow (not including shipping time). 

TRUFORMA Equine Insulin Assay 

The TRUFORMA equine insulin assay screens for insulin dysregulation using equine EDTA plasma, with two run protocols: a Default protocol for general screening (dynamic range 7.5–400 µU/mL) and an Auto Dilute protocol for follow-up on high-concentration samples (100–1,500 µU/mL). Precision data showed a coefficient of variation of 7.1–10.2% for the Default protocol and 5.6–6.8% for Auto Dilute — and correlation with radioimmunoassay reached R=0.98 across 114 equine samples. 

The fast turnaround makes TRUFORMA particularly well-suited to OST workflows, where a 60–90 minute post-challenge draw can be processed and interpreted the same day — ideally before the horse owner leaves the property. 

Together, these two assays give equine practitioners the ability to test for the two most significant endocrine drivers of laminitis in a single clinic visit — with reference-lab quality results in hand before the horse owner leaves. 

What BAW Technology Means in Practice 

Unlike traditional enzyme-based immunoassays that rely on optical detection, BAW biosensors measure the mass accumulated on a sensor surface directly, creating a frequency shift proportional to the amount of analyte present. The result is a highly precise, reliable measurement that doesn’t require large, expensive instrumentation or radioactive substances — and that performs consistently across instruments and operators. The compact, simple design of the TRUFORMA platform requires minimal training and fits into field and clinic workflows without disruption. 

What This Means for Your Practice 

For equine vets, the ability to test and treat in the same visit isn’t just a clinical advantage — it’s a practice differentiator. 

When a horse owner brings in a laminitis case and you can run an eACTH and insulin panel on-site, explain the results in real time, and begin a treatment conversation before they leave, you’ve delivered a different level of care. That builds trust, reduces the back-and-forth of callback consultations, and positions your practice as a progressive, well-equipped resource for equine health. 

Early detection of PPID and insulin dysregulation also means earlier treatment — which reduces the risk of laminitis episodes, more severe disease progression, and the difficult conversations that come with advanced cases. For the horse, earlier is better. For the horse owner, earlier is reassuring. For your practice, delivering that kind of proactive care is meaningful. 

Zomedica’s Customer Appreciation Program provides the TRUFORMA instrument with no capital outlay and no monthly minimums — lowering the barrier to bringing this technology in-house. Contact us to learn more! 

Frequently Asked Questions About Laminitis in Horses 

What is laminitis in horses? 

Laminitis is inflammation of the laminae, the tissue bonding the coffin bone to the inner hoof wall. It causes significant pain and lameness, and in severe cases can lead to permanent structural damage of the hoof. It is often a sign of an underlying systemic condition rather than a standalone disease. 

What causes laminitis in horses? 

Laminitis has several potential triggers, but endocrine disorders — particularly insulin dysregulation and PPID  — are among the conditions most frequently associated with its development. Other triggers include dietary carbohydrate overload, systemic illness, and mechanical overloading of a limb. 

What are the signs of laminitis in a horse? 

The classic signs include a laminitic stance (weight shifted to the hindquarters), bounding digital pulse, heat in the hooves, and reluctance to move. Chronic cases may show hoof wall changes such as founder rings or a dished toe. 

Can laminitis be cured? 

Acute laminitis can often be managed effectively with early intervention, particularly when the underlying cause is identified and addressed. Chronic laminitis with significant coffin bone rotation is more difficult to reverse, though many horses can be managed to a good quality of life with appropriate farriery, diet, and medical management. 

How is PPID connected to laminitis? 

PPID causes overproduction of ACTH, which leads to elevated cortisol levels. This hormonal dysregulation disrupts normal metabolic processes and is thought to increases a horse’s susceptibility to laminitis — particularly during the autumn seasonal ACTH rise. 

How is insulin dysregulation diagnosed in horses? 

Resting insulin measurement and the oral sugar test (OST) are the primary diagnostic tools. The OST measures insulin response to a sugar challenge and is the preferred screening method for horses on managed diets. Point-of-care testing with the TRUFORMA platform allows for fast, in-clinic insulin measurement, making same-visit diagnosis and treatment planning possible. 

Ready to See the TRUFORMA Diagnostic Platform in Action? 

Laminitis will always be part of equine practice. But the diagnostic process that follows a laminitis diagnosis doesn’t have to mean days of waiting, sample handling uncertainty, and delayed treatment decisions. 

TRUFORMA gives you the tools to go further, faster — with reference lab quality results at the point of care, in under 20 minutes. 

Learn more about the TRUFORMA eACTH and Equine Insulin assays here, or contact your Zomedica sales representative to request a demo: 

734.369.2555  |  sales@zomedica.com  

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Disclaimer: The information provided on this blog is for general informational and educational purposes only. It is not intended as medical advice and should not be used as a substitute for professional medical guidance. Always consult a qualified healthcare provider before making any health‑related decisions.