What Is Founder In Horses? Understanding Equine Laminitis

Learning about potential health issues in horses can be daunting yet essential for those new to the world of horsemanship.

One such health concern in horses' feet is 'founder,' a common term for equine laminitis.

This condition, often causing significant distress to horses, can impact their quality of life and ability to perform. As a new horse owner, it's essential to understand what founder is, recognize its signs, learn prevention measures, and know what to do if your horse is affected.
​
This comprehensive guide aims to arm you with this vital knowledge, ensuring you're prepared to provide the best care for your equine companion.

Detecting founder in horses early can make a significant difference to their recovery.

The first signs of this condition often include changes in behavior and movement. Your horse might appear unusually anxious, and there may be noticeable alterations in how they walk or stand.

Most horses suffering from laminitis, or founder, may exhibit the classic "sawhorse" posture, rocking back to unload the front feet with the hind legs underneath and weight shifted to the hindquarters. More subtle signs could include a stilted gait or reluctance to walk on hard surfaces, though advanced cases can cause severe pain or even excruciating pain.

Closer inspection might reveal heat in the hooves or an increased digital pulse, another indication of foot distress. Some horses may also show signs of pain when their soles are pressed during a lameness evaluation using hoof testers, though hoof testing does have limits.

​ Contact your veterinarian immediately if you notice any of these symptoms, as early intervention can significantly improve the horse's prognosis.

Founder is often triggered by various conditions such as excessive consumption of starches and sugars, repeated concussive pressure (road founder), grain overload, excessive weight bearing on one limb due to a contra-lateral limb lameness (support limb laminitis), and systemic inflammatory responses due to illness or infection.

Excessive grain consumption can lead to a buildup of carbohydrates in the horse's hindgut, producing toxins that can damage the laminae.

Similarly, access to lush pasture, particularly in the spring, can lead to an overconsumption of rapidly fermentable carbohydrates and subsequent laminitis.

The systemic inflammatory response can occur secondary to conditions like colic, pleuropneumonia, or retained placenta in mares. During such systemic illnesses, inflammatory mediators are released into the bloodstream and can cause damage to the hoof's laminae. Black walnut shavings and potomac horse fever are additional triggers, and black walnut shavings can cause laminitis within 24–48 hours.

Horses suffering from Cushing's disease, also known as pituitary pars intermedia dysfunction, are also at a higher risk due to hormonal imbalances exacerbating the inflammatory response, especially in older horses, and horses over 15 have higher laminitis risk.

Understanding these common causes can be vital in preventing founder in horses by managing their diet, monitoring health conditions, and providing proper hoof care. Understanding predisposing factors and other risk factors helps reduce laminitis risk and prevent some horses from develop laminitis.

Dehydration can significantly impact the likelihood of a horse developing founder.

When a horse is dehydrated, it can reduce blood circulation throughout the body, including the hooves. Poor circulation can result in insufficient nutrient and oxygen delivery to the laminae, the tissue structures that attach the hoof wall to the coffin bone.
​
As these tissues are deprived of vital resources, they can become inflamed and damaged, potentially leading to founder. 

Obesity is one of several underlying metabolic conditions and metabolic disorders that can significantly increase a horse's risk of developing founder.

Carrying excess weight puts additional strain on the laminae within the horse's hooves, which can initiate an inflammatory response leading to founder. ​ Moreover, overweight horses often have imbalanced diets that may include high levels of carbohydrates and sugars. Such diets can induce insulin resistance, and overweight horses may also have insulin dysregulation as part of the broader underlying causes of founder.

Veterinarians diagnose founder in horses by combining a physical exam, a formal lameness evaluation, notable clinical signs, and, sometimes, diagnostic imaging.

Initially, a vet might observe the horse's stance and gait, as horses with founder often stand or walk in a distinctively cautious, tender manner. They may also use hoof testers during hoof testing to localize pain, check for an increased pulse in the foot or heat, and better identify the source of discomfort in horses affected.

Diagnostic imaging methods like radiography (X-rays) can reveal changes in the position of the bone within the hoof or an increase in the thickness of the keratinized tissues, indicating chronic founder. In acute laminitis cases, radiographs may not show immediate changes, but they still help monitor coffin bone rotation, a rotated coffin bone, hoof capsule alignment, and blood supply.

In some cases, vets might also use magnetic resonance imaging (MRI) for a more detailed view. Nerve blocks may also be used to determine whether pain is originating in the horse's foot. ​ While there is no definitive blood test to diagnose acute founder, blood tests can help identify endocrine disease such as Equine Metabolic Syndrome and pituitary pars intermedia dysfunction, and this is where equine practitioners apply veterinary medicine expertise.

Recovery and management of horses diagnosed with founder is a meticulous process that demands dedication. Working closely with a veterinarian and a farrier is paramount to establishing a tailored treatment plan that addresses the underlying cause and foot abnormalities. Treatment should also target the underlying causes, including equine nutrition issues and endocrine or metabolic contributors, to support hoof health over the long term.

Pain management is often the first step in the recovery process, and NSAIDs are a common option for relief; during a laminitis attack, cold water therapy to the horse's foot may also help reduce inflammation, while therapeutic shoeing techniques can alleviate discomfort and support the damaged structures within the foot.

Changes in diet, primarily aimed at reducing carbohydrate intake, can play a pivotal role in managing the condition. It is recommended that horse owners should consult with an equine nutritionist to devise a balanced diet that minimizes the risk of further laminitis episodes.

Regular exercise is also vital in recovery, but the intensity and duration should be carefully controlled to prevent exacerbating the condition. The aim is to promote blood flow and circulation without causing undue strain on the affected hooves. In some cases of severe lameness or chronic lameness, surgery may be needed to reduce the pull of the deep digital flexor tendon on the coffin bone.

Lastly, many horses recovering from founder require regular check-ups to monitor progress and adjust the treatment plan as necessary, including corrective trimming to improve hoof conformation and better distribute weight within the hoof capsule. This proactive approach means many horses recover, and even horses with serious founder can improve when treatment starts early and is monitored closely.

The effects of founder on a horse's hoof can be profound and detrimental if not treated promptly.

The condition primarily impacts the laminae, the sensitive connective tissue structures within the equine foot that are part of the hoof structure and suspend the coffin bone inside the hoof capsule. In a foundered horse, the laminae become inflamed and deteriorate, leading to a painful condition that can adversely affect the horse's mobility.

If the inflammation continues unabated, the coffin bone may start to rotate or sink in relation to the short pastern bone, often visible as a change in the hoof wall and sole angle, and clinicians assess coffin bone points and alignment changes on imaging. This condition, known as 'sinking founder,' can lead to persistent lameness and may require intensive treatment.

Chronic founder may also show divergent hoof rings and widened white lines. ​ In severe cases of founder, abscesses may form within the hoof due to the death and shedding of the laminae, and damage to the hoof structure can compromise the horse's body weight support, causing severe pain and necessitating additional therapeutic interventions.

In conclusion, founder, or laminitis, is a severe condition affecting a horse's health and mobility.

Understanding the signs of founder in horses is crucial for timely diagnosis and treatment.

The disease affects the hoof's sensitive laminae tissue, leading to inflammation, pain, and possible rotation or sinking of the coffin bone. This can cause changes in the hoof's angle, result in persistent lameness, and, in severe cases, lead to abscess formation.

Regular check-ups and proactive treatments significantly enhance recovery chances and reduce recurrence risks.
​
As horsemen, our awareness and prompt action can make a significant difference in managing this condition and ensuring our horses' recovery the best they can.

Yes, grass can indeed cause a horse to founder.

This is largely due to the high sugar content found in lush green grass.
​
When a horse's diet consists primarily of this type of grass, it can lead to an overconsumption of sugar. This excess sugar can disrupt the balance of bacteria in the horse's gut, releasing toxins into the bloodstream. These toxins then inflame the laminae in the hooves, causing laminitis or founder. Managing a horse's diet and grazing time is crucial to help prevent founder.

Laminitis and founder are often used interchangeably but represent different stages of the same disease process.

Laminitis refers to the inflammation of the laminae, the sensitive structures within the hoof that connect the hoof wall to the pedal (coffin) bone. This inflammation is the initial, acute stage of the disease.

On the other hand, founder refers to the chronic or long-term condition that occurs after laminitis develops first, with structural failure following repeated or poorly controlled inflammation.

In the case of founder, the persistent inflammation leads to damage of the laminae, causing the pedal bone to rotate or sink within the hoof.

Thus, while all foundered horses have experienced chronic laminitis, not all horses with acute laminitis will progress to founder. In laminitis in horses, acute inflammation can progress to founder when coffin bone rotation or sinking occurs.

Riding a foundered horse largely depends on the severity of the condition and the stage of recovery.

In the acute phase of laminitis or during an active founder episode, riding is strictly discouraged as it can exacerbate the condition and cause tremendous pain to the horse.

Once the condition is under control and the horse is not in pain, light riding might be possible under the careful supervision of a veterinarian. However, it's essential to remember that every horse is unique, and what works for one may not work for another.

It is always recommended to consult a veterinarian or an equine podiatrist before riding a foundered horse.
​
Long-term and frequent monitoring of the horse's condition and appropriate hoof care are critical in managing horse founder well.

Preventing founder in horses requires a multifaceted approach focused on managing risk factors through proper diet, regular exercise, and routine veterinary care.

Firstly, limit your horse's consumption of lush pasture grass, especially during the peak growth periods in spring and fall, as overeating can trigger laminitis. A balanced diet that is low in sugar, starch, and fiber can help maintain a healthy digestive system and control weight, thereby reducing the risk of founder. Extra care is also warranted for pregnant mares when long hooves, pasture conditions, and delayed trimming combine to increase founder risk.

Regular exercise is also essential to keep your horse physically fit and prevent obesity, a significant risk factor for founder.

Routine veterinary care, including regular hoof trimming and dental care, is critical to early detection and prevention of conditions like laminitis.

Furthermore, immediate treatment of infections or injuries and managing conditions like Equine Metabolic Syndrome or Cushing's disease can also prevent the progression to founder.

Always remember, prevention is better than cure, and keeping a watchful eye on your horse's overall health and behavior can be instrumental in preventing founder, especially in older horses, since Cushing's disease often affects horses over 15 years old and increases laminitis risk.