Laminitis is a devastating, very painful disease that occurs when inflammation interrupts blood flow to the internal structure that suspends the horse’s distal phalanx (coffin bone) within the hoof capsule. This often results in structural failure of the tissue, causing displacement of the bone with the hoof capsule. In severe cases the bone can come right through the bottom of the sole of the horse’s foot.
Precipitating factors associated with laminitis include:
Excessive or sudden exposure to sugars within the pasture, also called pasture-associated or "grass founder"; especially in early spring and fall when the grass is starting to grow
Endocrine Disease-Associated – diseases include Equine Metabolic Syndrome or Pituitary Pars Intermedia Dysfunction (PPID or Equine Cushing’s Disease)
High level of toxins in the horse’s blood stream which can occur due to grain overload, colitis, or severe systemic bacterial infections
Poor hoof care or foot diseases
Supporting-limb laminitis, which occurs when the horse excessively stands on one limb due to pain in the other, causing the limb that is excessively weight-bearing to develop laminitis
Excessive concussive forces applied to the feet; also called “road founder”
High fever; Potomac Horse Fever in particular has been associated with high fever and laminitis
High and/or prolonged exposure to corticosteroids
Retained placenta after foaling
Black Walnut shavings exposure due to the presence of a toxin
Most cases of laminitis can be prevented by mitigating risk factors.
Preventing obesity. The most important way you can prevent your horse from developing laminitis is by preventing obesity – an overweight horse is just a laminitis case waiting to happen, particularly in pony breeds and those that tend to be easy keepers. These horses are genetically engineered to derive energy from sparse vegetation – think of the mustangs that can survive on desert scrubland. When they are fed excessive amounts of starches and sugars, they pack on the pounds. Appropriate diet and exercise play a very important role in the overall health of your horse.
Limit access to pasture grass, especially in the early spring and fall when the grass is starting to grow. Despite the pasture grass being short, it is packed full of sugars, which is why we see an increased incidence of "grass founder." It is important to slowly reintroduce horses to growing green grass after periods of slow or no growth (winter and summer).
Identifying horses with an endocrine disease such as PPID and instigating treatment is key to keeping them healthy.
If your horse gets into the grain room, has a high fever or is otherwise sick, or has not passed their placenta within 2.5 to 3 hours of foaling, you need to contact your veterinarian immediately.
Laminitis is a very, very painful disease. Horses suffering from laminitis show signs of foot-soreness. They are reluctant to walk and turn, will shift weight back and forth on their front and hind feet, and will spend an increased amount of time laying down. Their feet will be warm to the touch and the digital pulses to their feet will be elevated. The most classic sign of laminitis is called the “sawhorse stance” when the horse is standing with most of its weight shifted back on its hind end.
Urgent Intervention & Treatment
It is important to note that there is a period of time where the horse will have very subtle signs of foot soreness prior to developing the very obvious and dramatic “sawhorse stance,” so it is important to be vigilant and to call your veterinarian immediately if your horse is becoming foot sore and is at an increased risk of laminitis.
The sooner a diagnosis is made and treatment instituted, the better the chances are of recovery.
Diagnosis is made via history, veterinary examination, and radiographic assessment to view the location of the bone within the hoof capsule. Treatment depends on the inciting cause, but usually includes anti-inflammatory medication, alterations in diet and exercise, and supportive foot care as well as appropriate treatment for the possible cause (nasogastric tubing for grain overload for example).
We are always learning more about this disease. Your veterinarian is a wealth of information concerning this topic. Routine veterinary care is key in prevention – your veterinarian can help you to determine possible risk factors and help come up with solutions to decrease your horse’s risk.
For more on laminitis, check out the following resources:
American Association of Equine Practitioners. “Laminitis: prevention and treatment”. AAEP.org, www.aaep.org/horsehealth/laminitis-prevention-treatment. Accessed 24 September 2019.