Laminitis is a painful condition affecting the sensitive laminae within the horse’s hoof. It can have several different causes, but diet, pasture and metabolic health are important factors in many horses, particularly during periods of rapid grass growth in spring and autumn.
Understanding the early warning signs and taking action quickly can make a significant difference to your horse’s comfort and long-term hoof health.
Laminitis vs Founder: What Is the Difference?
The terms laminitis and founder are often used interchangeably, but they are not quite the same thing.
Laminitis refers to inflammation and damage within the laminae, the sensitive structures that connect the hoof wall to the coffin bone. Laminitis can range from mild to severe and may occur without any visible changes to the position of the coffin bone.
Founder generally refers to the more severe or advanced consequences of laminitis, where the connection between the hoof wall and coffin bone becomes compromised. The coffin bone may rotate or sink within the hoof capsule. This can cause significant pain and long-term hoof changes.
In simple terms, laminitis is the disease process, while founder describes structural changes that can occur as a result of severe laminitis.
What Can Cause Laminitis?
There are several recognised triggers for laminitis, including:
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Sudden access to large amounts of grain or other rich feed
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Rapid changes in pasture
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High-sugar or high-carbohydrate forage
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Metabolic disorders such as insulin dysregulation
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Severe illness or infection
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Retained placenta in mares
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Certain medications
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Injury resulting in prolonged weight-bearing on another limb
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Exposure to some toxic substances
For many susceptible horses, pasture is an important consideration. Laminitis can occur when horses consume large amounts of rapidly growing or stressed grass, particularly during spring and autumn.
Why Can Spring and Autumn Grass Be a Problem?
Spring and autumn can be particularly challenging for horses prone to laminitis. Rapidly growing grass can contain higher levels of sugars and other nutrients, while changes in pasture conditions can alter the nutritional balance of the forage.
Even a horse that is eating a relatively controlled diet may consume significant amounts of grass when turned onto fresh growth. Short, lush grass following rain can be particularly tempting because horses can consume a surprisingly large amount in a short time.
Horses with metabolic issues or previous episodes of laminitis can be especially sensitive to these changes.
Fructans and Cool-Season Grasses
Cool-season grasses such as ryegrass can contain significant amounts of fructans, which are storage carbohydrates produced by the plant.
When large amounts of rapidly fermentable carbohydrates reach the hindgut, they can alter the microbial balance within the digestive system. This is one of the mechanisms that has been investigated in relation to pasture-associated laminitis.
For horses that are sensitive to grass, avoiding high-risk pasture conditions is often an important part of management.
Signs of Laminitis
Early signs can be subtle, so it is important to know what is normal for your horse.
Possible signs include:
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Walking stiffly or reluctantly
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Short, careful steps
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Shifting weight from one foot to another
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Increased digital pulse
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Heat in the hooves
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Rocking back onto the heels
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Sweating or appearing distressed
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Reluctance to move
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Lying down more than usual
Some horses may simply become unusually quiet or unwilling to move. Because horses can hide signs of pain, subtle changes in behaviour or movement should not be ignored.
If your horse is showing obvious pain, rocking back on the heels, reluctant to stand or unwilling to walk, prompt veterinary assessment is important.
Metabolic Signs to Watch For
A horse does not have to be obese to be susceptible to pasture-related laminitis.
Some horses may show signs associated with metabolic imbalance, including:
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Excess fat around the crest of the neck
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Fat deposits behind the shoulders or around the tail head
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Difficulty maintaining a healthy weight
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A tendency to gain weight easily
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Previous episodes of laminitis
These signs do not necessarily mean a horse will develop laminitis, but they can be useful indicators that diet and pasture management deserve closer attention.
Managing a Horse During a Laminitis Episode
If laminitis is suspected, the priority is to reduce further exposure to whatever may be contributing to the problem and keep the horse comfortable.
For grass-sensitive horses, this may mean removing access to green pasture and providing suitable forage in a safe, grass-free area. A dry lot, yard, arena or suitable track system can provide an alternative when pasture conditions are unsuitable.
The horse should still have continuous access to appropriate forage. Slow-feeder hay nets can help extend feeding time while reducing the speed at which hay is consumed.
Avoid making sudden dietary changes unless necessary, and ensure the horse continues to receive appropriate nutrition.
Hay and Forage Considerations
The quality and nutritional composition of hay is important for horses prone to laminitis.
Suitable meadow-type hays may be preferable to very rich forage, depending on the individual horse and its nutritional requirements.
Hay soaking is sometimes used to reduce water-soluble carbohydrates, particularly where weight management or sugar intake is a concern. However, the suitability of soaking depends on the type and quality of hay and the individual horse.
Exercise and Movement
Exercise is an important part of maintaining metabolic health in horses, but a horse experiencing an active and painful laminitis episode should not be forced to exercise.
Once the horse is comfortable and has recovered sufficiently, gradual movement can be reintroduced according to the individual horse’s condition.
Forcing a painful horse to walk can increase discomfort and may worsen hoof damage.
Hoof Care
Hoof care needs to be individualised according to the severity and stage of laminitis.
A horse with painful laminitis may struggle to stand for trimming, so timing and technique should be discussed with an experienced hoof-care professional.
Supportive hoof care and appropriate footing can be particularly important when there has been damage to the laminae or changes in the position of the coffin bone.
Preventing Future Episodes
Once a horse has experienced laminitis, careful management is important because they may be more susceptible to future episodes.
Helpful strategies can include:
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Monitor pasture carefully, particularly during spring and autumn.
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Avoid sudden access to lush, rapidly growing grass.
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Provide appropriate forage when pasture conditions are unsuitable.
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Maintain a healthy body condition.
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Consider the horse’s individual metabolic and nutritional needs.
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Introduce changes to diet and pasture gradually where possible.
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Monitor the digital pulse and learn what is normal for your horse.
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Pay attention to subtle changes in movement and behaviour.
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Maintain regular hoof care.
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Develop a pasture-management plan for horses that are particularly grass-sensitive.
Short grass is not necessarily safer simply because it is short. Horses can consume large quantities of fresh regrowth in a relatively short period, so the stage and condition of the pasture are important considerations.
When to Seek Help
Laminitis can become a serious and painful condition, and early intervention is important.
If your horse develops a strong digital pulse, becomes stiff or reluctant to move, shifts weight repeatedly, rocks back onto the heels or appears to be in significant pain, seek professional assessment promptly.
A horse that is unable to stand or walk comfortably requires urgent attention.
Supporting a Grass-Sensitive Horse
Managing a horse prone to laminitis is often about looking at the whole picture rather than focusing on one factor alone.
Pasture, forage, body condition, metabolic health, exercise, hoof care and individual nutritional requirements can all play a role.
If you are unsure what is contributing to your horse's problems or how to manage their diet and pasture, contact Greenpet for further information or complete our Horse Questionnaire.
Related reading: Feeding Grass-Affected Horses
Important: Laminitis can be painful and potentially serious. If you suspect your horse has active laminitis, particularly if they are very sore or reluctant to stand or move, seek prompt veterinary assessment.