Laminitis (commonly called “founder”) affects an estimated 7-14% of the world’s equine population. It’s the inflammation of the tiny, interwoven lamellae that attach a horse’s hoof to the underlying coffin bone (third phalanx, or P3) and support the horse’s entire body weight. Anything that impacts the integrity of the lamellae, such as inflammation, weakens their hold. This causes the coffin bone to displace within the hoof capsule and move toward the ground. The condition is very painful and is often life-threatening to horses.
Causes of Laminitis
The same disease has several different causes, which include:
- Endocrine-associated laminitis, which is the most common cause, occurs in horses with insulin dysregulation, often due to equine metabolic syndrome (EMS) or pituitary pars intermedia dysfunction (PPID, or equine Cushing’s disease ), and exacerbated by ingestion of starch and sugars in feed or pasture (grass founder).
- Sepsis-related laminitis is due to toxins in the bloodstream of sick horses (e.g., those with diarrhea, colic, retained placenta, or metritis—uterine infection);
- Supporting-limb laminitis, which is caused by excessive weight bearing on a limb as a result of a painful injury in the opposite limb (e.g., fracture).
Clinical Signs (Symptoms) of Laminitis in Horses
- Reluctance or inability to walk, or profound lameness;
- Frequent weight shifting;
- Abnormal stance and weight distribution to relieve pressure on the affected limb(s);
- Increased heart and respiratory rate, and sweating;
- Glazed, pained facial expression;
- Bounding digital arterial pulses; and
- Feet that are consistently warmer than usual to the touch.