Warm temperatures and plenty of moisture has brought on lots of lush, green grazing for all classes of livestock in the Ozarks this spring. For horse owners however, the excessive pasture forage brings with it a heightened concern over laminitis and founder.
Laminitis can be defined as inflammation of the soft tissues (lamina) that attach the equine skeleton to the hoof capsule. In effect, these structures support the entire weight of the horse and distribute that weight to the hoof wall and sole. Therefore, inflammation of these lamina and subsequent separation of the tissues is excruciatingly painful for the horse and often results in permanent damage to the structures within the foot. The changes that take place within the hoof due to founder can be career ending or even life threatening for many horses.
Most horse owners are familiar with horses that founder after an episode of grain overload, however, excessive grazing of lush spring pasture can also cause laminitis in much the same way. Other causes include acute colic, retained fetal membranes in mares, metabolic/endocrine disease and unilateral lameness.
It is estimated that approximately 15 percent of the U.S. population of horses will be affected with laminitis at some point in their lifetime with upwards of 75 percent experiencing a poor outcome. Treatment for this condition is often challenging as the pathophysiology of the disease is not fully understood. Still, horses that receive appropriate treatment and supportive care earlier in the course of disease can be expected to have a better chance for recovery and survival. Signs for horse owners to watch for include alternate lifting of the feet indicating pain, reluctance to move unless forced to do so, a stance in which the horse redistributes its weight to the hind limbs, heat over the surface of the hoof wall and swelling at the coronary band. If you notice these clinical signs in your horse I advise a prompt examination by your veterinarian.
If an inciting cause is known the first task in treating the disease is to eliminate the inciting cause. In cases of carbohydrate overload on pasture, the horse must be brought in off the grass. Limiting turnout is also a good way to prevent cases of laminitis especially in horses that may have had previous bouts with the disease. Next, your veterinarian will likely recommend a combination of therapies that may include anti-inflammatories/analgesics, stall rest, corrective trimming/shoeing and therapy directed at improving the bloodflow to the foot. Taking x-rays can allow for monitoring of the changes taking place within the foot, a more accurate prognosis and more precise trimming/shoeing by the farrier.
Keep in mind the clinical signs and risk factors associated with this disease and watch your horses closely this spring.
Darren Loula, DVM, is a large animal veterinarian at Fair Grove Vet Service in Fair Grove, Mo.
