One in ten horses is affected by laminitis each year. This painful condition involves inflammation of the hoof laminae, leading to varying degrees of lameness. [1]

Although laminitis affects the hooves, the condition is often initiated by dietary and metabolic factors. Laminitis can also result from infection or excessive mechanical stresses on the hooves.

Many horses recover completely, but others have lasting damage and are not able to resume their previous level of work.

Once a horse experiences laminitis the risk of reoccurrence increases, and proper management is critical to support recovery and maintain a sound horse.

All breeds and ages of horses are susceptible to laminitis, but some horses have a higher risk due to genetic factors. There are also common lifestyle factors that contribute to the development of this condition. [1]

This article will review the top 17 risk factors for laminitis in horses and discuss how to address these risk factors and prevent laminitis in your horse.

Laminitis Overview

Approximately 600 interlocking laminae in the horse’s foot provide structural support and connect the coffin bone to the hoof wall. When laminitis occurs, these soft tissue structures become inflamed and stretch, resulting in debilitating pain for the horse.

If the condition progresses to founder, the laminae eventually separate and the coffin bone loses support. The coffin bone may rotate downwards and create pressure on the sole.

Some horses fail to regain soundness after laminitis and struggle with the condition as a chronic issue. In severe cases, laminitis can lead to euthanasia – approximately, 7% of equine deaths are associated with laminitis. [2]

There are three main types of laminitis that can occur:

  • Endocrinopathic laminitis – relating to metabolic causes, such as grain overload or pasture-associated laminitis
  • Sepsis-associated laminitis – occurring as a secondary effect of illness
  • Mechanical laminitis – caused by excessive weight bearing or support limb laminitis

Regardless of whether laminitis is caused by mechanical, metabolic or other factors, the condition can worsen quickly. If laminitis progresses to founder, the hooves and inner structures of the lower leg may sustain irreversible changes and result in permanent lameness.

Typical Signs of Laminitis

Horses affected by laminitis commonly display physical and behavioural signs of the condition. There can also be changes in hoof quality and signs of metabolic dysfunction that indicate your horse is at risk of laminitis.

Physical and Behavioural Signs

Abnormal Stance: Affected horses avoid bearing weight on their front legs by positioning them in front of the body.

Objection to movement: The intense pain caused by laminitis can make horses reluctant to move.

Altered gaits: Horses with laminitis may be lame in some or all legs and exhibit a shortened stride.

Shifting weight: Horses with foot pain may alternate bearing weight on their legs by lifting them up and placing them down again.

Increased digital pulse: Horses with laminitis may have a stronger digital pulse caused by inflammation and restricted blood flow in the extremities.

Changes in Hoof Quality

Flaring of the hoof wall: A damaged laminar attachment between the coffin bone and the hoof wall can cause the hoof to flare or have a dished appearance.

Rings on the hooves: Inflamed laminae and restricted blood supply to the hoof can initiate the development of hoof rings.

Stretched white line: Located around the inner edge of the hoof, the white line can become elongated when the laminar connection is unhealthy.

Metabolic Disturbances

  1. High insulin levels: Increased insulin levels are a known precursor for laminitis. [3][4]
  2. Obesity: A key contributor for equine metabolic syndrome, obesity is associated with a higher incidence of laminitis. [5]
  3. Regional fat deposits: Horses with laminitis may exhibit accumulations of fat deposits in areas including the neck, withers, rump, and genitalia.

Top 17 Risk Factors for Laminitis

Research on equine laminitis has identified several risk factors for the condition. [6] Understanding these factors is critical to reducing your horse’s risk profile and preventing adverse outcomes.

Although laminitis may not always be preventable in every case, good management practices can help you improve your horse’s prognosis. Below are 17 of the most common risk factors for laminitis.

1) A Previous Attack of Laminitis

Horses that have had acute laminitis in the past may have sustained damage to the internal structures of their hooves, making them more vulnerable to the condition in the future.

Laminitic horses can experience recurrence of the condition if the original risk factors that caused the first episode of laminitis were not fully addressed.

Horses that have recurrent episodes of laminitis may experience chronic inflammation in their hooves. This inflammation may not completely resolve between flare-ups, although the horse can appear more sound at times as they learn to compensate. [19]

Preventive strategy:

A veterinarian should assess your horse to determine if a case of laminitis has completely resolved. This assessment will typically involve blood testing and reviewing the horse’s full medical history and current work regimen.

Work with a nutritionist to design a feeding plan that supports your horse’s recovery and reduces the likelihood of recurrence.

2) Genetics

Certain breeds of horses are genetically predisposed to laminitis. The condition occurs more frequently in easy keeper breeds, which have one or more genes that promote survival during times of drought and feed scarcity.

Certain genes may predispose horses to metabolic dysfunction and laminitis by promoting excess fat storage. Breeds such as Saddlebreds, Morgans, Paso Fino and Welsh and Dartmoor ponies are considered more vulnerable to equine metabolic syndrome and laminitis. [20]

Preventive strategy:

Determine if your horse is a high-risk breed or has a high prevalence of laminitis among relatives. Easy keepers need to have their diets closely managed to avoid this condition.

Know the warning signs of laminitis so it can be treated promptly if your horse develops the condition.

3) Diets High in Sugar and Starch

Feeding a diet high in non-structural carbohydrate (NSC) components including starch, sugars, and fructans from grain or lush pasture increase the risk of laminitis in horses.

Excess NSCs readily ferment in the hindgut and promote acidosis, which can result in a loss of beneficial bacteria in their large intestine.

These alterations in the gut flora and the resulting dysbiosis can stimulate an immune response that affects the laminae of the hooves and can result in laminitis.

Preventive strategy:

Feed a diet predominantly comprised of hay that is low in NSC and high in fiber (structural carbohydrates). Reduce or eliminate concentrates such as grain and sweet feeds in the diet.

4) Access to Lush Pasture

Quality pasture can be a valuable component of a healthy diet for your horse. However, certain types of pasture plants can contain high amounts of sugar, starch, and fructans, which increase the risk of laminitis.

Several factors including weather, maturity, time of year, and the time of day influence the amount of NSCs in pasture grass.

Lush grasses may provide more nutrients than horses need, particularly in the springtime when the grass is growing quickly and is rich in calories. However, grass can be a hazard to laminitis-prone horses at any time of year.

Preventive strategy:

Avoid turnout in lush pasture and feed your horse hay that has been appropriately selected to match their energy needs.

Horses vulnerable to laminitis should be fed forages that contain less than 10% NSC. Get a hay analysis to ensure you are choosing the right forage for your horse.

Horses at risk of laminitis may require turnout with a grazing muzzle or appropriate pasture management strategies, such as strip grazing. Grazing horses in the early morning before the sun rises is recommended because the NSC content of grass is lowest at this time of day.

Do not turn your laminitic horse out in the morning if the overnight temperatures have dropped below 5°C or 40°F. At these low temperatures, plants will stop growing and retain sugar, resulting in higher NSC levels for horses grazing in the morning.

5) New Access to Grass

Horses that are newly turned out onto grass after having no access to grass for four weeks or more have a much higher risk of developing laminitis.

These horses were seven times more likely to become laminitic compared to horses that had continuous access to grass or no access to grass. [6]

Preventive strategy:

Gradually transition your horse to turnout on pasture after a long period of time with no pasture access, such as in the springtime. Consider pasture management strategies such as wearing a grazing muzzle, strip grazing or turning out for limited periods of time when NSC levels are lowest in grass.

6) Pituitary Pars Intermedia Dysfunction (PPID)

Horses with PPID (sometimes referred to as Equine Cushing’s Disease) have a higher risk of developing laminitis. [7] A research study in Finland involving 36 horses with laminitis determined that 89% had PPID. [8]

PPID is a metabolic condition that causes excessive production of the hormone adrenocorticotropin (ACTH) and a resulting increase in cortisol levels. High blood cortisol levels promote elevated insulin, which is directly associated with an increased laminitis risk.

Signs of PPID include an excessively long hair coat, reduced muscle mass, lethargy, and increased susceptibility to infections. Laminitis is a key indicator of PPID.

Preventive strategy:

If your horse is showing signs of PPID, consult with a veterinarian to have your horse’s blood tested. The standard treatment for PPID is the oral administration of the drug pergolide.

Pergolide may help to improve hormonal imbalances in horses with PPID, but dietary management is still critical to restrict the intake of NSCs. Horses with PPID should be tested annually to determine if their medication dosage requires adjustment.

7) Insulin Resistance (IR)

Horses with insulin resistance (IR) are unable to properly respond to insulin, a hormone that allows cells to metabolize sugar for energy production. As insulin sensitivity decreases, the pancreas responds by secreting more of this hormone. [9][10]

In IR horses, insulin remains at a high level for a prolonged period, causing systemic problems that can increase susceptibility to laminitis. Research suggests a direct link between elevated insulin levels and the development of laminitis.

Preventive strategy:

Horses suspected of being insulin resistant should undergo diagnostic blood testing to detect the condition. Horses with IR typically require diets low in NSCs and an appropriate exercise regimen to manage their condition.

8) Excess Fat Deposits

Obese horses are at a significantly higher risk for laminitis because excessive fat deposits promote insulin resistance. Adipose tissue (fat) deposits on the crest of the neck, belly, and tailhead have altered metabolic processes that make cells less responsive to insulin.

Where on the body your horse tends to store excess fat may be more important than overall body condition for determining laminitis risk.

A research study involving 26 ponies compared the relative metabolic risk for overall body condition scores to scores of fat deposits on the neck. The study found that the neck score was more predictive of insulin dysregulation than an overall body condition score. [12]

Preventive strategy:

Horses that are prone to storing excess fat require careful management. These horses typically benefit from a calorie-restricted diet that is low in NSCs and an appropriate exercise program.

If your horse develops fat deposits on the neck – known as a cresty neck – consult with a nutritionist for strategies to reverse this condition.

9) Recent Weight Gain

Horses that have gained weight in the last 3 months have a nearly four-fold increase in their risk of laminitis. Recent weight gain indicates a diet that is over-supplying energy or could mean that your horse’s activity level has decreased. [6]

Preventive strategy:

Regularly body condition score your horse and make adjustments to their diet and exercise program if you notice that your horse is gaining weight.

10) Exposure to Black Walnut Shavings

Contact with or ingestion of black walnut shavings is a known cause of laminitis in horses. Exposure to black walnut shavings can lead to acute laminitis within one to two days by altering blood flow to the hoof and exerting other systemic effects.

Preventive strategy:

Avoid using black walnut shavings for bedding stalls or in other areas where horses are kept.

11) Acute Illness

Illnesses such as colic, pneumonia, diarrhea, and inflammation in the small intestine can promote the development of laminitis by making it easier for toxins to penetrate the intestinal barrier and circulate into the bloodstream.

Upon entry into the peripheral blood supply, these toxins can impede circulation through the lamellar tissues and activate enzymes that weaken the laminae. [21]

Mares who retain their placenta after giving birth or who develop inflammation in their uterus (metritis) also have a risk of laminitis if toxins are released into the bloodstream. [22]

Preventive strategy:

Ensure your horse is regularly examined by a veterinarian and promptly treat any illness to reduce the risk of laminitis.

Mares that have recently given birth should be assessed to ensure the placenta is not retained.

12) Trauma to the Hoof

Mechanical laminitis can occur if the wall of the hoof becomes separated from the bone or is severely compromised causing damage to the underlying laminae.

Trauma to the hoof wall due to poor hoof care, excessive concussion, or improper hot shoeing can cause damage to the laminae and result in laminitis.

Preventive strategy:

Provide regular hoof care for your horse from a qualified farrier using proper trimming and/or shoeing practices. Treat any hoof injuries promptly to avoid complications that could lead to laminitis.

13) Soft Tissue Injury

Horses with soft tissue injuries, including ligament and tendon injuries, are more likely to develop laminitis after their injury. [11]

These injuries occur most frequently in active sport horses between the ages of 11 to 15 years. Injured horses are typically given limited turnout and have long periods of inactivity or field rest. [11]

Laminitis may develop in response to prolonged periods without exercise and inadequate adjustment of the diet, resulting in metabolic or circulatory issues.

Preventive strategy:

Speak with a veterinarian to develop a training and rehabilitation program that supports your horse’s recovery. Avoid restricting movement for longer than necessary and adjust your horse’s diet to match their energy demands while recovering from an injury.

14) Stall Rest

Horses that need to be put on stall or box rest should be managed carefully to avoid laminitis. Stall rest is defined as being confined to a stable or shelter for 24 hours per day with no exercise.

One study found that horses on stall rest during the previous week had a three-fold increase in their risk of acute laminitis. This may be linked to changes in feeding and exercise patterns. [6]

Horses on stall rest are also often suffering from injuries and may be more likely to develop supporting limb laminitis (SLL). This mechanical form of laminitis occurs when the horse shifts weight from an injured limb to the opposite limb, resulting in excessive weight-bearing. [6]

Preventive strategy:

If your horse is on stall rest for an injury, monitor them closely and speak to your veterinarian about strategies to prevent SLL. One study found that raising the heel on the supporting foot can improve blood flow and reduce the risk of supporting limb laminitis. [18]

15) Sudden Temperature Drops

Laminitis is most commonly associated with springtime in the minds of horse owners, but cold winter conditions can also predispose a horse to laminitis. [6]

One study found that horses were four times more likely to develop laminitis between the months of December to February compared to March to May. [6]

This increase in risk is not fully understood. However, a sudden decrease in temperature can impair circulation to the hooves, leading to pain and inflammation.

Preventive strategy:

Horses that are already at an elevated risk for laminitis should be carefully monitored in the winter for signs of foot soreness. Follow this guide on caring for your horse in the winter.

16) Signs of Foot Soreness

Horses that appear to be lame or foot-sore after receiving farrier care have a higher risk of laminitis.

These horses may develop laminitis as a result of poor shoeing or trimming practices. [6] However, it’s also possible that the farrier care draws attention to previously unnoticed signs of laminitis.

Preventive strategy:

Seek veterinary attention for horses that show signs of foot soreness after shoeing or trimming. Prompt care may help to prevent a serious adverse outcome.

17) Use of NSAID Medications

Horses given non-steroidal anti-inflammatories (NSAIDs) for pain had a higher risk of developing laminitis. These drugs – such as phenylbutazone – are commonly used in older horses to address arthritic joint pain.

NSAIDs may promote laminitis by altering the gut microbiome and increasing the risk of leaky gut syndrome. [11]

Preventive strategy:

Ask your veterinarian about COX-2 selective pain medications, which are safer for the gut than traditional NSAIDs. Avoid long-term use of NSAID medications and always follow dosage guidelines closely.

If your horse uses NSAIDs to address joint pain, consider safe supplement options that help to promote joint health and have a lower risk of side effects.

Summary

There are many steps you can take to help lower your horse’s risk of laminits. Some of the most important feeding and management practices to adhere to include:

  • Feed a diet low in NSCs – Feed a low sugar, low starch, forage-based diet and avoid grains and commercial feeds that raise insulin levels and increase inflammation.
  • Regularly Monitor Weight – Check your horse’s weight and body condition regularly. Adjust your horse’s diet, exercise, and other management factors as needed.
  • Provide Regular Farrier Care – Ensure your horse receives regular trimming/shoeing from a qualified farrier to maintain healthy hooves.
  • Treat Metabolic Disease: Horses with insulin resistance and PPID should be treated to reduce the risk of laminitis.

Make sure that your horse’s diet provides all of the essential nutrients required for healthy hoof growth. Key nutrients include amino acids, biotin, and microminerals including copper and zinc. [13][14][15][16][17]

Mad Barn’s AminoTrace+ is a vitamin and mineral supplement specifically designed for horses at risk of laminitis. AminoTrace+ provides balanced levels of nutrients for hoof health and metabolic function, while also supporting gut health, antioxidant status and overall well-being.

AminoTrace+ Equine Supplement

AminoTrace+

5 stars
79%
4 stars
8%
3 stars
3%
2 stars
5%
1 star
6%

Learn More

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

Speak to a nutritionist to design a balanced feeding plan to reduce your horse’s risk of laminitis. Submit your horse’s information online for a free consultation.

Is Your Horse's Diet Missing Anything?

Identify gaps in your horse's nutrition program to optimize their well-being.

References

  1. Pollard, D. et al. Incidence and clinical signs of owner-reported equine laminitis in a cohort of horses and ponies in Great Britain. Equine Vet J. 2019.
  2. Pollard, D. et al. Factors associated with euthanasia in horses and ponies enrolled in a laminitis cohort study in Great Britain. Prev Vet Med. 2020.
  3. Morgan, R. et al. Equine metabolic syndrome. Vet Rec. 2015;177(7):173-179. doi:10.1136/vr.103226
  4. De Laat MA. Et al. Phenotypic, hormonal, and clinical characteristics of equine endocrinopathic laminitis. J Vet Intern Med. 2019.
  5. Morgan, RA. et al. Vascular Dysfunction in Horses with Endocrinopathic Laminitis. Journal PLOS One 2016.
  6. Wylie CE et al. Risk factors for equine laminitis: a case-control study conducted in veterinary-registered horses and ponies in Great Britain between 2009 and 2011. Vet J. 2013
  7. Grenager NS. Endocrinopathic Laminitis. Vet Clin North Am Equine Pract. 2021.
  8. N.P. Karikoski et al. The prevalence of endocrinopathic laminitis among horses presented for laminitis at a first-opinion/referral equine hospital. Domestic Animal Endocrinology. 2011.
  9. Treiber KH et al. Insulin resistance in equids: possible role in laminitis. J Nutr. 2006.
  10. 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.
  11. Gauff, F et al. Hyperinsulinaemia increases vascular resistance and endothelin-1 expression in the equine digit. Equine Vet J. 2013.
  12. Fitzgerald, DM. et al. The cresty neck score is an independent predictor of insulin dysregulation in ponies. PLoS ONE. 2019.
  13. Comben, N. et al. Clinical observations on the response of equine hoof defects to dietary supplementation with biotin. Vet Rec. 1984.
  14. Josseck, H. et al. Hoof horn abnormalities in Lipizzaner horses and the effect of dietary on macroscopic aspects of hoof horn quality. Equine Vet J. 1995.
  15. Geyer, H. and Schulze, J. The long-term influence of biotin supplementation on hoof horn quality in horses. Schweizer Archiv fur Tierheilkunde. 1993.
  16. Reilly, J.D. et al. Effect of supplementary dietary biotin on hoof growth and hoof growth rate in ponies: a controlled trial. Equine Vet J. 2010.
  17. Buffa, Eugene et al. Effect of dietary biotin supplement on equine hoof horn growth rate and hardness. Equine Vet J. 1992.
  18. Orsini, JA et al. Supporting limb laminitis: The four important ‘whys’. Equine Vet J. 2012.
  19. Steelman, S.M. and Chowdhary, B.P. Plasma proteomics shows an elevation of the anti-inflammatory protein APOA-IV in chronic equine laminitis. BMC Vet Res. 2012.
  20. McCue, M.E. et al. Equine Metabolic Syndrome: A Complex Disease Influenced by Genetics and the Environment. J Equine Vet Sci. 2015.
  21. Bailey, S.R. et al. Current research and theories on the pathogenesis of acute laminitis in the horse. The Vet J. 2004.
  22. Parsons, C.S. et al. Risk factors for development of acute laminitis in horses during hospitalization: 73 cases (1997–2004). J Am Vet Med Assoc. 2007.