Laminitis in Horses

Laminitis has three distinct causes, each resulting in separation of the lamellae within the hoof.

Sepsis-Associated laminitis occurs when there is severe inflammation throughout the body from an infection. The lamellae become inflamed, weakening the connective tissue and reducing their weight-bearing capacity.

Supporting Limb laminitis occurs when horses are not bearing weight on another limb. The limb across from the affected limb is under constant stress, and often must support the horse’s entire weight. Over time, the excessive weight leads to separation of the lamellae.

Endocrinopathic laminitis occurs in horses with disorders affecting their hormone regulation.

Laminitis is a common and severe condition in horses. Horses suddenly showing symptoms of laminitis, such as lameness at the walk or “sawhorse stance," require emergency veterinary attention. Chronic laminitis often shows more subtle symptoms until it progresses to severe disease. Horses showing symptoms of lameness, uneven hoof growth, and increased time spent lying down require prompt veterinary care.

Laminitis has two major forms: acute (occurring suddenly) and chronic (developing over long periods). Symptoms vary slightly between the two forms.

Acute laminitis is most commonly associated with sepsis-induced or supporting-limb laminitis.

Chronic laminitis symptoms are initially mild, and increase in severity over time.

As chronic laminitis progresses, more severe symptoms develop, such as

• “Sawhorse stance”
• Dished appearance to the hoof wall, with an excessively long toe
• Unwillingness to rise from lying down
• Weight loss due to limited mobility preventing them from accessing feed
• Penetration of the coffin bone through the sole of the hoof

Laminitis occurs when the supportive structures that hold the coffin bone in place within the hoof begin to separate. These supportive structures, called the lamellae, are highly sensitive, making this separation extremely painful.

The most common disorders causing endocrinopathic laminitis are equine metabolic syndrome and equine Cushing’s syndrome, also known as PPID. Excessive use of steroids to treat immune disorders such as skin allergies or heaves can also result in this type of laminitis. The exact mechanism behind the lamellar damage in these cases is unknown, but is thought to be related to insulin levels.

Diagnosis begins with a physical examination and lameness exam. Physical examination is particularly important to identify any other symptoms that may suggest sepsis-induced laminitis. Further diagnostics to confirm laminitis include:

• Blood work
• Diagnostic imaging, particularly x-rays of the hooves to identify lamellar separation
• If other symptoms are present, specific testing to confirm underlying conditions

Treatment depends on the type of laminitis present, but focuses on treating the underlying cause. While treatment is occurring, the laminitis itself must be treated to reduce pain and discomfort. Supportive care for laminitis depends on whether it is acute or chronic.

Acute laminitis cases benefit from:

• Aggressive anti-inflammatory therapy
• Continuous cooling or icing of the feet
• Specialized shoeing or booting to support the frog and sole
• Strict stall rest on sand bedding to support the foot
• Sling support during standing in severe cases

Horses with chronic laminitis require long-term treatment to restore the lamellar support structures. On top of managing the underlying condition, these horses may require:

• Long-term NSAID therapy
• Gradual shoeing or trimming changes to adjust hoof balance
• Shoeing or booting to support the frog and sole
• Routine hoof x-rays to monitor progress
• Surgical intervention to relieve tension on the lamellae

Laminitis requires prompt, aggressive treatment to reduce the risk of long-term consequences. The outcome of laminitis cases depends on the severity of lamellar damage and the success of treatment. Most horses with mild cases of laminitis are able to return to athletic activity after appropriate treatment and rehabilitation. Moderate cases of laminitis are unlikely to return to an athletic career, but can often be kept comfortable in retirement. Both mild and moderate cases require long-term follow-up and monitoring to identify any future laminitic episodes quickly. Horses with endocrinopathic laminitis require extensive management to prevent laminitic episodes from reoccurring.

Severe cases of laminitis, particularly cases where the coffin bone “sinks” due to damage to the lamellae around the entire hoof wall, or where the coffin bone penetrates the hoof sole, have a poor prognosis. Often, these horses develop severe, chronic lameness that interferes with their quality of life, even if the laminitis is treated. These horses are often euthanized.

There are no specific preventatives for laminitis; however, routine veterinary examination can identify early risk factors associated with endocrinopathic laminitis. Managing at-risk horses primarily involves dietary changes to reduce their risk of laminitic episodes. Observing best management practices, including weight control and exercise recommendations also help prevent laminitis. Laminitis is not contagious.

Laminitis is common in horses.

• Stall rest
• Anti-inflammatories
• Specialized shoeing or trimming
• Icing the feet