Feeding the Laminitis-Prone Horse – Diet, Prevention & Recovery

If you have a horse prone to laminitis, deciding what to feed can be stressful. Feeding a diet that is too rich in sugars can make things worse for your horse and lead to flare-ups.

But there are some simple rules you can follow to feed your horse appropriately and reduce the risk of an acute laminitis episode.

Laminitis is a systemic health condition that manifests in the hooves. It is often linked to metabolic dysfunction and can be triggered by carbohydrate overload in the diet.

Horses with chronic laminitis have experienced one or more episodes of acute laminitis and may have long-term hoof damage. In one study, 3.9% of horses were reported to have chronic laminitis. ^[19]

Designing a feeding plan for a laminitic horse involves getting a hay analysis and reducing the non-structural carbohydrate (NSC) content in the diet. You may need to stop feeding commercial grains, limit pasture access, and provide a vitamin and mineral supplement to support hoof growth.

Our nutritionists can help you formulate a long-term management diet for your laminitic horse. Submit their information online for a free diet evaluation.

Laminitis: An Overview

Laminitis is an extremely painful and debilitating condition that can cause long-term damage in horses. Some horses are permanently affected and are unable to return to work or to the same performance level.

This condition involves inflammation of the laminae found within the hoof capsule. The laminae are a soft tissue structure consisting of blood vessels, connective tissue, and nerves.

The laminae attach the pedal bone (third phalanx) to the hoof wall. Inflammation causes the laminae and pedal bone to separate, weakening the connection between the pedal bone and the hoof wall.

In the most severe cases, laminitis can progress to founder in which the pedal bone sinks distally (downwards) and rotates within the hoof capsule. In extreme cases it can puncture through the hoof sole. ^[1]

Not only does this lead to lameness, but it also disrupts circulation to the hooves. Laminitis has been described as equivalent to a heart attack in the hoof. ^[20]

Horses that have foundered experience excruciating pain. Horse owners may have no choice in these cases but to make the difficult decision to euthanize their companions.

If your horse is showing signs of acute laminitis, consult with a veterinarian right away. Acute laminitis is a medical emergency.

Once the acute stage of the condition has passed, work with your veterinarian and farrier for a treatment plan to resolve symptoms.

You should also consult with an equine nutritionist to identify dietary and management changes that can help to reduce the risk of laminitis recurrence.

Common Causes of Laminitis

Several types of laminitis have been identified based on different causal factors.

Laminitis can be caused by starch overload due to chronic over-consumption of concentrates or rich grass. Laminitis can also occur in a horse that escapes into the feed room and consumes large quantities of grain in a short period.

This is referred to as endocrinopathic laminitis. This form is primarily mediated by metabolic dysfunction and is related to problems with insulin regulation.

Laminitis can also be caused secondary to colitis or to an infection linked to a retained placenta in post-parturition mares (after giving birth). This is known as sepsis associated laminitis.

Lastly, mechanical laminitis can occur if a horse is overcompensating for a lameness or through excessive concussion in exercise. ^[2]

Depending on the type of laminitis your horse is dealing with, there are different strategies to manage their risk.

In this article, we will focus on management practices to reduce the risk of endocrinopathic forms of laminitis, which represents 90% of cases in horses and ponies. ^[21]

Many of these cases are caused by dietary factors that are linked to domestic management. This means that many cases of laminitis are preventable with the right feeding, exercise and management strategy.

Reducing the Risk of Endocrinopathic Laminitis

Endocrinopathic laminitis is most commonly seen in overweight horses or ponies with Equine metabolic syndrome (EMS), insulin resistance, or Cushing’s syndrome (PPID).

It is linked to diets high in sugar and starch as well as unrestricted grazing on lush pastures. Affected horses may also have limited exercise or turnout.

Horses that have suffered from laminitis in the past are also more prone to developing laminitis again unless significant changes to diet and management are made. ^[1] The rate of recurrence for endocrinopathic laminitis is 34.1%. ^[22]

Fortunately, there are several effective strategies to reduce the risk of recurrence in lamanitic horses. These include:

• Reducing the amount of soluble carbohydrates that your horse eats
• Feeding a forage-first diet with hay or pasture that matches your horse’s needs
• Supporting weight loss if your horse is carrying excess body condition
• Supporting your horse’s gut health
• Providing adequate opportunities for turnout and exercise, where appropriate
• Feeding vitamins and minerals that support metabolic health
• Soaking hay, using hay nets or grazing muzzles, and pasture management

How to Feed a Laminitic Horse

The main consideration when feeding a laminitis-prone horse is the amount of soluble carbohydrates in the overall diet.

Soluble carbohydrates consist of water-soluble carbohydrates (WSC), ethanol-soluble carbohydrates (ESC) and starch. These are the non-structural carbohydrates (NSC) found within plant cells and are easily digested in the gut.

The ESC and starch fractions of soluble carbohydrates are those that can trigger insulin secretion from the pancreas and contribute to metabolic dysfunction. Therefore, these are the fractions that should be limited in overweight or EMS horses.

These carbohydrates are rapidly broken down to simple sugars by enzymes in the small intestine. They are quickly absorbed from the gut and spike blood sugar levels.

The WSC fraction can also contribute to laminitis risk. This fraction contains fructans which are sugar compounds high in fructose. Fructans are digested in the hindgut by microbes that produce lactic acid. This can alter the microbial environment and cause damage to the intestinal lining. This allows absorption of toxins that trigger inflammation in the body and contribute to laminitis.

Consuming too much sugar and starch over a long time or in a single meal can lead to laminitis in your horse.

Feeding plans should be designed to provide less than 10 – 12% NSC (ESC + starch), while ensuring your horse receives all vitamins, minerals, essential fatty acids, protein, and fibre that they require.

Maintaining a Healthy Body Condition

It is important to determine the weight and body condition score (BCS) of your horse before making any dietary changes.

Body condition scoring is a way of assessing whether your horse is the optimal conditon based on the degree to which the horse is covered by fat.

The neck, body, and hindquarters are examined to determine how much fat is deposited in these areas. Fat will typically feel softer and spongier than muscle. A hard neck crest could indicate insulin resistance or EMS.

BSC Scale

BCS is often conducted using the 9-point Henneke scale. This scale grades horses as: [5]

1. Poor (emaciated)
2. Very thin
3. Thin
4. Moderately thin
5. Moderate (ideal)
6. Moderately fleshy
7. Overweight
8. Obese
9. Very obese

Horses that are prone to laminitis should be maintained at 4-5 on the BCS scale. Horses that are 7 and over have an increased risk of laminitis. ^[23] If your horse is 3 or below, they are underweight and may need to carefully gain some weight.

A nutritionist can help you formulate a diet to support optimal body condition by adjusting the digestible energy content of the ration.

Body Weight

You should also regularly weigh your horse to ensure they are at a healthy weight. Weighing also allows for accurate dosing of medications, such as for wormers and metabolic drugs.

Ideally, use a weigh bridge. A weight tape can be used if a weight bridge is not available. Weight tapes are not as accurate but are a useful tool for monitoring whether your horse is gaining or losing weight. ^[6]

Supporting Gut Health

The gut plays a critical role in starch-induced laminitis – the most common form of this condition. Therefore, the feeding program for a laminitic horse should be formulated to promote gut health and support microbial balance.

Starch-induced laminitis is caused by alterations in the microbial population of the gastrointestinal tract. This is known as microbial dysbiosis. ^[2]

Starch overload can result from feeding greater than 1 gram of starch per kilogram of bodyweight per day. For example, feeding 500 grams (17.5 oz) of starch to a 500 kg (1100 lb) horse in a single meal can lead to starch overload.

Overload occurs when there is too much starch consumed at one time for all of the starch to be broken down and absorbed from the small intestine. The excess starch reaches the hindgut where it alters the bacterial population.

Microbial Dysbiosis

In thie hindgut, starch and fructans promote the proliferation of undesirable gram-positive bacteria, such as Streptococci. The result is hindgut acidosis, in which the gastrointestinal pH falls below pH 6.

Low gastrointestinal pH destroys the good gram-negative microbes, which have a protective effect on the horse. ^[1] These symbiotic bacteria support immune function and nutrient digestion.

When these beneficial microbes are destroyed, toxins are released from them and absorbed through the gut wall (gastrointestinal mucosa). These toxins enter the vascular system and are circulated throughout the body (systemically).

Systemic release of these toxins causes constriction of blood vessels (vasoconstriction). This is particularly noticeable in the sensitive, highly perfused, laminae of the hoof. ^[3]

Constriction of blood vessels in the laminae results in inflammation and can ultimately lead to the separation of the pedal bone from the laminae.

In severe cases, the pedal bone rotates and sinks distally within the hoof capsule, puncturing the hoof sole, and exposing corium (pedal bone membrane) to the environment. ^[4] This advanced condition is known as founder.

Given the role of gut dysfunction in the development of laminitis, supporting the microbiome is an important step in preventing this condition.

What to Feed a Laminitic Horse

Which feeds are safe for you to give your laminitis-prone horse? A nutritionist can help you select forages and feeds that are low in sugar and starch and available in your region.

There are also a number of nutrients that you can give your horse to support metabolic health and reduce the risk of laminitis.

How you feed your horse can also impact laminitis risk. We will discuss some recommended management practices below to reduce your horse’s risk of developing this condition.

Always follow these four golden rules of feeding to support overall health and wellbeing:

1. Feed small amounts often
2. Feed according to workload and bodyweight
3. Feed adequate forage (minimum 1.5% bodyweight unless on veterinarian advice)
4. Make all changes gradually

Forage

Forage should make up 80 – 100% of the laminitic horse’s diet, depending on their workload, body weight and whether they have active laminitis or are being fed to prevent laminitis.

Fibre-rich forages, such as grass, hay, haylage, silage, straw, and chaff, are broken down by microbes in the gut to produce volatile fatty acids (VFAs). VFAs provide slow-release energy for the horse and should be the main energy source in the diet.

Grass

Pasture grass can contain up to 15% simple sugars plus fructans (complex sugars). If given free access to pasture, horses can consume 5% of their body weight in grass within a few hours. ^[7]

This means horses can rapidly consume large quantities of sugar if grazing on rich grass pasture. For this reason, horses with a history of laminitis or uncontrolled EMS or insulin resistance should not be allowed unrestricted access to grass pasture.

If your horse is at an ideal weight and is not currently suffering from acute laminitis, they may be allowed to consume small quantities of carefully managed grass pastures.

Your horse should be closely monitored for signs that laminitis is developing. Consider using a grazing muzzle to reduce total intake.

Types of Grasses

A mixture of grasses is best rather than a monoculture pasture of high-calorie or sugary grass.

Laminitic horses and easy keepers generally do best on pastures with a combination of warm-season (such as coastal Bermuda) and cool-season grasses (such as timothy, fescue, and orchard grass).

Be careful to avoid grasses that can contain toxins such as Sudan grass, Johnson grass and alsike. ^[8]

Turnout Management

You can reduce sugar intake and laminitis risk when your horse is turned out by following these strategies: ^[7]

• Turn out your horse overnight, in the early morning or in the late evening. Grass fructan content is highest during the day when maximal photosynthesis is occurring.
• Avoid turnout when the ground is frosty. During frost, the grass is stressed and not growing, so it stores fructans and other sugars meaning it has higher sugar content.
• Grass that has flowered and gone to seed has significantly lower fructan content than flowering or pre-flowering grass.
• Avoid overgrazing and don’t let grass length go below 4 inches. Fructan content is highest in the stems and lowest in the leaves.

Grass Pasture Management

To help reduce the sugar intake for your horse that is prone to laminitis, there are some pasture management techniques to consider: ^[9]

• Strip grazing: Parts of the field are fenced off, and horses are allowed to graze small sections at a time. Be careful not to overgraze the field.
• Bare/Sparse paddock: For the horse that needs to lose weight, turnout on a dry lot or bare paddock is an option to restrict calorie intake. Provide your horse with soaked hay, straw or low-sugar hay to ensure forage is available at all times. Be careful of poisonous plants and shrubs growing on the bare paddock.
• Track system: Sometimes referred to as a pasture paradise, a track is created around a field by fencing. Amenities, such as food, water, and shelter, are spread out around the track system, encouraging the horse to exercise.
• Natural environment: Turnout your horse in a natural environment such as moorland, rocky mountainous land, woodland, or desert areas. This enables the laminitic horse to forage and explore while consuming low-calorie grasses. Be careful of poisonous plants or shrubs and make sure your horse has shelter and freshwater available.
• Native unimproved pasture: Turnout your horse on grass that has not been fertilized or harrowed or on pasture with grass species that have not been genetically improved. Many grass species have been bred to provide more calories for dairy cows and ranches.

Grazing Muzzles

A grazing muzzle can limit your horse’s sugar intake while allowing turnout within a social grouping. This can help to reduce boredom and prevent stereotypic behaviours.

Research shows that wearing a grazing muzzle decreases grass consumption by around 80%. ^[14] Using a grazing muzzle for 10 hours during the day and removing it overnight has also been shown to promote weight loss in overweight ponies that were allowed free access to grass pasture. ^[15]

The locomotion and natural behaviour of most horses are not affected by grazing muzzles. As long as your horse is gradually acclimatized to wearing the muzzle over three weeks, it will not cause aggression, stereotypical behaviours, or stress. ^[16][17]

Ensure your horse is able to drink water while wearing the grazing muzzle. Your horse will have reduced intake when wearing a muzzle, so it is critical to feed a vitamin and mineral supplement and allow free access to salt when your horse is not wearing the muzzle.

Weigh and body condition score your horse weekly while using a grazing muzzle. You should also assess your horse’s behaviour regularly while they wear the muzzle.

Some easy keepers will still gain weight even when wearing a grazing muzzle. Consider other grazing options for these horses.

Hay and Silage

When selecting hay for your laminitic horse, ensure the hay has a moderate-to-low sugar content, is of good quality, free from mould, clean, and dry.

Mature cut hay from a native or unimproved grass is ideal for laminitic horses. It will have lower sugar content than early cut grass. Hay cut late in the season should only be used if the grass was not exposed to temperatures less than 4 degrees Celsius before cutting. ^[7]

It is recommended to send your forage off for nutrient analysis to determine carbohydrate content. Your hay analysis will tell you levels for the following macronutrients: ^[7]

• Water soluble carbohydrates (WSCs): Complex sugars found in grass and hay/haylage/silage. WSC content should ideally not exceed 8-10% in forage fed to the laminitic horse.
• Non-structural carbohydrates (NSCs): ESC plus starch found within grass, hay, haylage and silage. NSC content should ideally not exceed 10% in forage fed to the laminitic horse.

Soaking Hay

If your dry forage analysis shows a high sugar content (ESC and WSC) then the forage can be soaked to help reduce the sugar content. ^[9]

To maximize WSC reduction in hay, it needs to be soaked for a minimum of 8 hours. Soaking hay for 12-16 hours in cold water has been found to reduce sugars by up to 50% in some hay types. ^[10][11]

However, soaking the hay for such a long time also significantly reduces palatability, mineral levels, amino acid content and increases relative fibre content. In hot weather, bacteria and fungi can breed rapidly in the water.

Shorter duration of soaking can be sufficient to remove enough WSC to bring it below 10%. In several studies, soaking for 15 – 30 minutes in warm water was enough to reduce the WSC content to acceptable levels while limiting mineral and amino acid loss. ^[24][25]

Due to mineral loss with soaking, a vitamin and mineral supplement must be fed to avoid deficiencies in the diet.

How to Soak Forage

The following are some key points when soaking forage: ^[9]

• Soak in warm water for 15 – 30 minutes (1 hour in cold water) to reduce sugar content
• Consider soaking for up to 8 hours in acute laminitis cases for maximal sugar reduction
• Use a hay net to make it easier to transport the forage
• Change the water every time hay is soaked
• Only soak fresh, clean, mould-free forage
• Use as much water volume as possible to remove more sugar
• Dispose of the contaminated water carefully, in accordance with your local guidelines

Straw

Straw has lower nutritional value and contains less sugar than other types of forage. It is sometimes fed to overweight laminitic horses that require fewer calories and a low sugar diet.

Research shows that horses fed straw have lower blood insulin levels compared to horses that are not fed straw. This can have positive implications for obesity, equine metabolic syndrome, insulin resistance, and laminitis risk. ^[12]

Straw also takes much longer to chew than other forages. This means that it extends eating time for horses on a restricted diet, reducing the incidence of stereotypical behaviours and equine gastric ulcer syndrome (EGUS). ^[12]

Oat and wheat straw are both suitable for laminitic horses, providing the straw is clean, dry, and free from mould. Straw is available in bales, or as chopped chaff.

Straw should be introduced very gradually into the diet over a period of a few weeks. For horses at high risk of laminitis, straw can be fed at 50% of the diet alongside soaked hay.

How much Forage should I Feed?

When managing the diet of a laminitic horse, not only do you need to select a forage that is low in sugar, you also need to ensure that your horse is not eating too much or too little forage.

The quantity of forage provided should be based on the weight, body condition, and workload of the horse.

Laminitis-prone horses should not be fed less than 1.5% of their bodyweight in forage per day, unless on the advice of your veterinarian. For a 500 kg (1100 lb) horse, this means feeding 7.5 kg (16.50 lb) of forage per day.

Feeding less than this and inducing rapid weight loss can lead to a metabolic condition known as hyperlipidemia. Other conditions such as ulcers, colic, and stereotypical behaviours can also stem from low forage intake.

Hyperlipidemia is particularly concerning because it can increase the risk of laminitis and is a potentially fatal condition. ^[7]

Feeding Rate

For a horse to maintain its current weight, feed 2% of its body weight in forage per day. A 500 kg (1100 lb) horse at maintenance should be fed 10 kg (22 lb) forage every day.

To promote weight loss, feed 1.5% of its body weight per day in forage. A 500 kg (1100 lb) horse should be feed 7.5 kg (16.50 lb) of forage to help them lose weight.

If your horse has little-to-no access to grass pasture and is fed a mature low-sugar hay and/or straw, they may be fed forage at 2% body weight and still achieve weight loss.

For weight gain, a horse should be fed 2.5 – 3% of its body weight in forage per day. A 500 kg (1100 lb) horse should be fed 12.5 – 15 kg (27.5 – 33 lb) forage daily for safe weight gain.

It is important to monitor your horse’s workload and body condition score regularly. You may need to adjust the feeding rate as your horse’s weight changes.

Concentrate Feeds and Chaff

Concentrates and chaff should be limited in the laminitic horse’s diet. However, sometimes you may need to feed a small amount of concentrate as a carrier for supplements, medications or vitamins and minerals.

Overweight horses should only be fed low sugar unmolassed chaff, such as straw blended with low sugar alfalfa. Avoid feeding grains or high-starch feeds.

Horses that are underweight and need to gain weight can also be fed a low sugar unmolassed chaff, unmolassed sugar beet pulp, or oil such as micronized linseed or W-3 oil.

Oil is a safe supplement to help hard keepers gain weight because it is composed of fat and contains negligible sugar. Oil can be fed at up to 100 mL per 100 kg bodyweight in horses that are severely underweight.

Fat should be introduced into the diet gradually over 6 weeks. Choose fats that provide omega-3 fatty acids, which have an anti-inflammatory effect on the body.

Vitamin and Minerals

Laminitic horses are typically on a calorie-restricted forage-based diet and may be wearing a grazing muzzle or consuming soaked hay. This can limit the intake of essential vitamins and minerals that are required to support health.

It is always important to feed your horse a balanced vitamin and mineral supplement to cover gaps in the diet. Vitamins and minerals are required to support metabolic processes such as making proteins and metabolizing sugars. Therefore, deficits can contribute to insulin resistance and poor hoof health.

Laminitic horses also have the same protein requirements as non-laminitic horses of the same weight and workload. ^[9]

A forage balancer or vitamin and mineral supplement should support all of the horse’s daily requirements for vitamins, minerals, essential fatty acids and amino acids (particularly lysine). ^[13]

Supplements for laminitic horses tend to have higher levels of key antioxidants, vitamins and minerals involved in hoof health and metabolic regulation. These include zinc, copper, magnesium and chromium.

Mad Barn’s AminoTrace+ is a vitamin and mineral supplement targeted to the needs of laminitic horses. It contains organic trace minerals, full vitamin fortification, and added antioxidants in a low-NSC pellet that is suitable for metabolic horses.

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• Complete mineral balance
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• Promote hoof & coat growth

Salt

Sodium is commonly deficient in the equine diet. But there is an easy solution: provide free-choice access to plain loose salt (sodium chloride) at all times.

We recommend adding 1 -2 tablespoons of salt to your horse’s feed daily. Salt licks or blocks are not recommended as they do not get used enough to meet their sodium requirement.

Electrolytes may also be required if your horse sweats a lot in hot weather or when doing regular hard work.

Probiotics

Supplementing a probiotic can help your horse maintain a stable gastrointestinal environment, contributing to a lower risk of laminitis. Probiotics also promote optimal forage digestion and immune function. ^[1][2][18]

A primary cause of laminitis is gut dysbiosis and the release of endotoxins as bacteria die off following starch-induced alterations in gastrointestinal pH.

This is best avoided by reducing starch content in the diet. However, feeding a gut health supplement can also support the microbiome and reduce the risk of hindgut acidosis.

Mad Barn’s Optimum Digestive Health is an advanced prebiotic/probiotic formula that supplies 20 billion viable colony forming units (CFUs) of five desirable microbial strains per serving. Optimum Digestive Health also contains yeast, digestives enzymes and a proprietary blend of immune nucleotides.

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• Prebiotics, probiotics & enzymes
• Support hindgut development
• Combats harmful toxins in feed
• Complete GI tract coverage

Summary

Below are some key points to remember when feeding a laminitic horse:

• Feed to achieve an ideal body condition score
• Feed a minimum 1.5% bodyweight as forage unless advised by your veterinarian
• Choose forages that are low in soluble carbohydrates
• Soak hay to reduce carbohydrate levels
• Monitor your horse for signs of insulin resistance, EMS, and Cushing’s Syndrome
• Follow good grazing management practices; turnout your horse with a grazing muzzle, on rough low quality pasture, or overnight unless frosty
• Feed up to 50% of the diet as straw to reduce calorie density while providing adequate dry matter
• Always feed a vitamin and mineral supplement and free choice loose salt to prevent deficiencies in the diet
• Supplement with a probiotic gut health formula

Our nutritionists can help you formulate a balanced feeding program to reduce the risk of laminitis. Submit your horse’s information online for a free nutrition consultation.