Laminitis has several distinct triggers, and understanding which one applies to your horse is central to both treatment and long-term prevention.
Pasture and grass-associated causes are among the most common, particularly in spring and autumn when pasture grasses are high in sugars and fructans. Horses grazing on lush, rapidly growing grass can experience a sudden overload of soluble carbohydrates in the hindgut, disrupting the microbial balance and triggering an inflammatory cascade that reaches the laminae. This risk is significantly higher in horses with Equine Metabolic Syndrome (EMS), a condition characterised by insulin resistance and often accompanied by regional fat deposits, such as a thickened neck crest.
Cushing's disease, or PPID (Pituitary Pars Intermedia Dysfunction), is another major cause, particularly in older horses and ponies. PPID disrupts hormone regulation in ways that can drive persistently high insulin levels, leaving affected horses vulnerable to laminitis even outside the typical spring grass season.
Obesity and insulin dysregulation go hand in hand with both EMS and PPID. Elevated insulin appears to have a direct, damaging effect on the laminae, which is why weight management is such a central part of laminitis prevention.
Beyond metabolic causes, mechanical laminitis, sometimes called road founder, can result from prolonged concussion on hard surfaces or excessive weight-bearing on one limb due to injury elsewhere. This form is less about hormonal imbalance and more about repeated physical stress on structures that were never designed to absorb that much impact.
Retained placenta in mares after foaling is another recognised trigger, thought to arise when toxins from the retained tissue enter the bloodstream and disrupt normal laminar function within days of birth. Similarly, systemic illness or sepsis, such as severe colic, colitis or infection elsewhere in the body, can trigger what is known as sepsis-related laminitis. In these cases, the inflammatory response set off by the underlying illness spreads through the bloodstream and damages the laminae in all four feet at once, which is why horses recovering from serious systemic disease are watched so closely for early hoof changes.
