Hot hooves, a sawhorse stance, severe lameness; these are all signs of laminitis – one of the most dreaded equine conditions for good reason. In severe instances, laminitis can lead to euthanasia of the horse.

Laminitis occurs when there is separation in the laminae of the hoof — where the hoof wall is connected to the coffin bone. It can occur in one or multiple hooves at the same time.

The separation can lead to permanent structural changes in the foot and lasting lameness. It can sometimes result in severe coffin bone rotation and the coffin bone may even puncture the sole of the hoof.

Researchers have learned that laminitis does not strike out of nowhere. Instead, there are often early warning signs and a prolonged subclinical phase before full-blown laminitis appears. [1]

If you can learn to recognize these signs in your horse, then the chances of identifying and hopefully reversing the condition before it becomes severe are much improved.

How Laminitis Occurs

While laminitis was once considered to be a disease in and of itself, researchers now agree that it is a clinical syndrome associated with systemic disease including endocrine disease, sepsis, or systemic inflammatory response syndrome.

Researchers believe that more than 90% of horses that develop laminitis have an underlying endocrine disease, usually Equine Metabolic Syndrome (EMS).

When laminitis is associated with metabolic disease, it is known as endocrinopathic laminitis.

There are usually triggering factors related to metabolic health that lead up to episodes of full blown laminitis. The most common trigger is an increased intake of carbohydrates, such as a horse getting too much grass or grain.

Excess Carbohydrates and Endotoxins

When carbohydrate overload occurs, the small intestine which usually digests starches becomes overwhelmed. The undigested starches spill over into the hindgut, which mainly digests fiber.

Starch digestion in the hindgut increases hindgut acidity which causes a shift in the microbial population of the hindgut as beneficial bacterial colonies begin to die off.

Components of these dead microbes, known as endotoxins, can be absorbed into the bloodstream and trigger an immune response.

This endotoxemia results in systemic inflammation, which usually leads to laminitis. [2]

Supporting Limb Laminitis

Another less common type of laminitis is known as supporting limb laminitis. This occurs when a significant injury causes a horse to bear too much weight on the opposite limb.

This form of laminitis can also lead to structural breakdown of the laminae and coffin bone rotation.

Stages of Laminitis

With most cases of laminitis, there are generally three recognized stages:

1) Subclinical laminitis: minor changes occur within the hoof but the horse only shows subtle signs.

2) Acute laminitis: horse shows signs of pain in the feet, ranging from mild to severe.

3) Chronic laminitis: occurs when a horse has had several episodes of laminitis which have caused physical changes in the hooves. This usually includes coffin bone rotation. Horses with chronic laminitis are at high risk for continued episodes.

Prevalence and Risk Factors

Unfortunately, laminitis is a highly prevalent condition affecting many horses worldwide. In a 1998 survey, 13% of US horse operations reported having a horse with laminitis. Of affected horses, nearly 5% had to be euthanized due to laminitis. [13]

However, acute laminitis can occur in any horse that consumes a large amount of carbohydrates at once, such as when a horse gets into the grain bin or when transitioning to lush pasture in the spring. In an owner-reported survey, over 50% of the cases were suspected to be due to grazing lush pasture or grain overload. [13]

Genetics may also affect risk of laminitis.Pony breeds and some large horse breeds such as Saddlebreds, Morgans, Tennessee Walking Horses, Paso Finos, and Quarter Horses are at higher risk for developing metabolic conditions and endocrinopathic laminitis.

Dewormers, bute, and other medications can also trigger acute laminitis in some horses.

Early Warning Signs of Laminitis

Laminitis often starts at the cellular level well before a horse becomes lame. Because of this, there are subtle warning signs that show up before major problems occur.

Being vigilant for these signs and taking immediate measures might mean the difference between a mild case of laminitis and one that becomes completely debilitating.

Many early signs of laminitis first appear as changes in the hooves. Regular farrier care is one of the best ways to monitor and protect the health of your horse.

Some of the most common early warning signs of laminitis in horses include:

1) Hoof Wall Distortion

When the hoof laminae is healthy and the attachment between the coffin bone and hoof is strong, the foot will maintain a compact form, without distortion.

However, any changes in the hoof wall – such as toes that grow long quickly or toes that have a dished or flared appearance – could signify that your horse has subclinical laminitis.

Your farrier can help to reduce long toes or flares, but dietary changes are needed to prevent hoof wall distortion from continually reoccurring.

2) Hoof Rings

Hoof rings show up as a deviation around the hoof wall from the coronary band. These rings form due to inflammation in the lamina with a decrease in blood supply.

Various stressors can cause hoof rings to form. These include a change in diet, seasonal fluctuations in grass quality, or environmental changes.

Laminitis is also a common cause of hoof rings, even in the early stages of the disease.

Hoof rings caused by laminitis appear slightly different from hoof rings caused by other factors. Instead of being evenly spaced around the hoof wall, laminitis rings stand slightly upward because of an uneven growth rate of the heels and toes.

If your horse shows signs of hoof rings, it may signify a window of opportunity for therapeutic intervention before the condition worsens. [3]

3) Loss of Sole Concavity

Some horses are more flat-footed than others, but if your horse has become more flat-footed than normal, this is another indicator of subclinical laminitis.

Loss of sole concavity is more common in the front feet and occurs when the coffin bone begins to rotate within the hoof capsule.

Horses with a loss of sole concavity may be more prone to bruising. Also, shoes may add to the pressure on the sole and result in lameness.

4) Stretched White Line

The white line (a misnomer because it isn’t actually white) appears around the inner edge of the hoof wall as seen from the bottom of the hoof.

When metabolic problems occur, this line can become stretched, forming a small gap around the edge of the sole. This gap may collect dirt, small rocks, or even rotting material.

Researchers say that a stretched white line is often the earliest noticeable change in horses with metabolic conditions such as insulin resistance. [3] A stretched white line indicates the beginning of laminar failure, but the good news is that it can be reversed in many instances.

5) Seedy Toe or Fungal Infection

Fungal infection often goes hand in hand with a stretched white line. Seedy toe and white line disease are similar fungal or bacterial infections of the hoof that can be caused by mechanical problems such as overgrown toes. These infections can also be a telltale sign of subclinical laminitis.

If you see rotting material inside the stretched white line or hear a hollow sound when tapping on the outside of the hoof wall, your horse likely has seedy toe or white line disease.

These infections can often be treated with anti-fungal or anti-microbial soaks and proper trimming. If subclinical laminitis is to blame, the problem will likely return unless dietary changes are made.

6) Chronic Abscessing

If your horse tends to get frequent hoof abscesses, this is another warning sign of an underlying condition such as laminitis.

Hoof abscesses can occur within the hoof wall, beneath the sole, or anywhere inside the hoof capsule. Abscesses often result in extreme lameness, which is only relieved when the abscess gravitates to the surface of the hoof and drains.

Some abscesses are minor and only become noticeable when they break through the hoof wall, often leaving small holes or cracks.

If you see changes in your horse’s hooves or if your horse tends to abscess every spring or multiple times throughout the year, a visit with your veterinarian is warranted.

7) Gait Abnormalities

If your horse develops a shortened stride or any kind of foot lameness, this may be an early indicator of laminitis.

When there is pain in the hooves, your horse’s gait will change as they attempt to relieve pressure. Horses with subclinical laminitis try to relieve pressure on their toes which can result in gait abnormalities.

8) Foot Lifting

When pain or pressure occurs in the hooves, horses may also lift their feet more than normal or frequently shift their weight. Horses may also refuse to lift a foot to avoid the pain of bearing weight on the opposite limb.

Too much foot lifting or a reluctance to lift the feet are subtle signs of laminitis.

9) Generalized Foot Soreness

Generalized foot soreness may show up as sensitivity to having the feet cleaned, a reluctance to move over hard ground, or a reluctance to walk downhill or even turn.

Soreness after shoeing or trimming has also been associated with higher rates of laminitis. [4]

10) Increased Digital Pulse

The digital pulse can be felt as blood flows through the artery into a horse’s hoof. If there is inflammation of the tissues in the leg or hoof, blood flow will be restricted.

This makes the pulse stronger and easier to feel. A pulse that is easy to find and bounding can be an early indicator of laminitis. [5]

When feeling for the digital pulse, use the index and middle fingers to feel on both the outside and inside of the leg just above the fetlock. Also, feel over the fetlock and down the pastern.

Do not use your thumb as you may end up feeling your own pulse instead of the horse’s. [5]

11) Increased Hoof Temperature

A warm hoof indicates inflammation occurring inside the hoof capsule. This can occur with an abscess or other types of hoof injuries, but it is also a common indicator of the beginning stages of laminitis.

Soaking warm hooves in ice water is recommended to decrease inflammation and slow the progression of laminitis.

12) Increased Insulin Levels

Horses with subtle signs of laminitis typically have underlying metabolic conditions which contribute to hoof changes in the first place.

Blood tests performed by your veterinarian may show increased insulin levels and your horse may be diagnosed with insulin resistance.

Insulin resistance is the failure of tissues to adequately respond to circulating insulin. [6] As tissues become less sensitive to the effects of insulin, more of this hormone is released causing levels to rise.

Dietary changes and exercise are needed to improve insulin sensitivity. This includes lowering the starch and sugar content of their diet by eliminating grains and transitioning to a forage-based diet.

13) Obesity

Obesity is the main known risk factor for Equine Metabolic Syndrome and often is associated with early stages of laminitis.

Using the Henneke Body Condition Scoring system is the best way to evaluate your horse’s obesity status. A score of 7 or more indicates that your horse is carrying too much body fat and needs to lose weight. [6]

However, it is important to note that non-obese or even thin horses can experience metabolic problems and laminitis.

14) Regional Adiposity

Regional adiposity or fatty deposits that accumulate in certain areas such as along the top of the neck, on the rump, behind the withers, or around the genitalia are a reliable indicator of metabolic disease.

If you notice regional adiposity, especially a cresty neck, your horse may have sub-clinical laminitis. [7]

What to Do if Your Horse Shows Signs of Laminitis

Subclinical laminitis can occur over a prolonged period that can last for years. However, if you notice any of the above warning signs, it’s best to take action immediately.

Work with your veterinarian or a nutritionist to change your horse’s diet and address any underlying metabolic issues.

We recommend taking a hay sample and submitting it for analysis to get the most accurate information about your horse’s current diet.

Avoid sweet feeds, grains, or high-sugar treats. Additionally, your horse may need to be removed from pasture and fed low sugar (or soaked) hay instead.

Increased exercise can also benefit horses showing signs of laminitis. Exercise promotes insulin sensitivity, encourages weight loss and increases blood flow to the feet.

However, you should only increase exercise if your horse isn’t lame or extremely foot sore. Working your horse on softer ground such as grass, sand, or in an arena is best.

Nutrition for Horses at Risk of Laminitis

Balanced nutrition is key to building out strong hooves and supporting your horse’s metabolic health.

To support hoof health, horses require adequate amounts of amino acids, trace minerals such as zinc and copper, and the B-vitamin biotin.

Many equine diets are lacking in this nutrients, which may cause problems for hoof health. Feeding a comprehensive vitamin and mineral supplement, such as Mad Barn’s AminoTrace+, will help to address common gaps in the diet and support hoof health.

AminoTrace+ Equine Supplement

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  • Complete mineral balance
  • Supports metabolic health
  • Formulated for IR/Cushing's horses
  • Promote hoof & coat growth

AminoTrace+ is specifically formulated for horses at risk of laminitis and other metabolic issues. It is a low-NSC formula that contains elevated levels of nutrients to support insulin sensitivity.

Two minerals that are particularly important for insulin resistant horses include magnesium and chromium.

Magnesium is involved in metabolic function and low levels of this mineral are associated with insulin resistance. [8] Supplementing with magnesium oxide is a good option for any horse that is deficient in this mineral.

Chromium is another essential mineral that many metabolic horses may be lacking. Chromium is required to synthesize glucose tolerance factor (GTF), which binds to insulin to enhance its action within the body.

One study led researchers to conclude that supplementing with 4 mg of chromium daily can enhance insulin sensitivity and even prevent horses from becoming insulin resistant later in life. [9]

If your horse is displaying warning signs of laminitis, submit their information online for a free review by our equine nutritionists. Our nutritionists can help you design a feeding plan to prevent or recover from laminitis.

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References

  1. Patterson-Kane, J.C. et al. Paradigm shifts in understanding equine laminitis. The Vet. Journal. 2018.
  2. Carbohydrate Overload. Fox Valley Equine Practice.
  3. Geor, R.J. and Harris, P.A. Laminitis. Equine Applied and Clinical Nutrition. 2013.
  4. Pollard, D. et al. Identification of modifiable factors associated with owner-reported equine laminitis in Britain using a web-based cohort study approach. BMC Vet Res. 2019.
  5. Equine Digital Pulses. Willamette Valley Equine Veterinary Services.
  6. Morgan, R. et al. Equine metabolic syndrome. Vet Rec. 2015.
  7. Fitzgerald, D.M., et al. The cresty neck score is an independent predictor of insulin dysregulation in ponies. PLoS One. 2019.
  8. Winter, J.C. et al. Relationship between intracellular free magnesium concentration and the degree of insulin resistance in horses with equine metabolic syndrome. Pferdeheilkunde – Equine Med. 2020.
  9. Spears, J.W. et al. Chromium propionate increases insulin sensitivity in horses following oral and intravenous carbohydrate administration. J Anim Sci. 2020.
  10. de Laat, M.A. et al. Toll-like receptor and pro-inflammatory cytokine expression during prolonged hyperinsulinaemia in horses: Implications for laminitis. Vet Immunology and Immunopathology. 2013.
  11. Pollard, D. et al. Assessment of horse owners’ ability to recognise equine laminitis: A cross-sectional study of 93 veterinary diagnosed cases in Great Britain. Equine Vet J. 2017.
  12. Winter, J.C. et al. Oral supplementation of magnesium aspartate hydrochloride in horses with Equine Metabolic Syndrome.. Pferdeheilkunde – Equine Med. 2016.
  13. USDA Lameness and laminitis in US Horses. USDA. 2000.