Laminitis in Racehorses

Laminitis is a word that strikes fear in the hearts of every horse owner, be it family horses or racehorses. In 1989, the magnificent Secretariat was euthanized because of laminitis; a similar fate was suffered more recently by Barbaro, the people’s hero, who also contracted laminitis after suffering a broken leg. When humans decided to domesticate horses, their diets and workloads changed dramatically from what they were accustomed to in the wild, and this has opened the door to illnesses and injuries which would probably not have occurred had they remained wild. But there is hope for horses with laminitis, depending on the severity, and as more research is done into laminitis, the more is learnt and preventative measures developed.

To understand laminitis, one has to understand the hoof of a horse. It is one of the most spectacular features of the horse, as it is superbly designed to withstand the weight of the horse and protect its legs by absorbing most of the pressure sustained when running. The foot of a horse consists firstly of the hoof wall, which is what is seen when a horse is standing. The hoof wall is extremely strong and serves the function of protecting the inner mechanisms of the hoof. In much the same way as a human nail, the hoof grows continuously to produce new and strong layers.

On the inside of the hoof wall is an uncountable number of lamellae, better described as tissues folds, of which there are two different types, and these lamellae connect the pedal bone of the horse, to the hoof wall. As the horse moves, the lamella extends and compresses to absorb any forces put on the hoof. When these lamellae begin to tear apart from the inner hoof wall, the pedal bone is no longer connected to the hoof wall, and this is start of laminitis which causes unbearable pain for the horse. The gap that is now present between the hoof and the lamellae causes the buildup of fluids, which in turn causes the lamellae to become inflamed and cut off vital oxygen and blood to the hoof. If left untreated, the worst case scenario could happen, that of the pedal bone tearing away from the hoof wall and sinking through the hoof tissues.

It is believed that laminitis occurs more frequently in racehorses, which is likely due to their high grain diet that is combined with very little or no roughage. Although laminitis can happen to any horse, it is found to be the Thoroughbred that suffers from it most frequently suggesting that genetics may also play a role. Although laminitis does sometimes occur without warning, there are a few factors to look out for that often leads to laminitis, such as infections, horses with musculoskeletal issues, prolonged use of antibiotics, overworking on hard ground, hormonal imbalances and stress put on an opposite limb to due injury and carrying extra weight. Owners will be able to notice the onset of laminitis through signs such as a horse constantly shifting its weight, being restless, warmth on the hoof, reluctance to walk, throbbing pulse in the hoof, ridges in the hoof and sore or bruised soles.

X-rays and venograms will determine the severity of the laminitis. Depending on the stage of laminitis the horse is in, farriers and veterinarians will work together to assist the horse by providing therapeutic shoeing which would alleviate the pain, assist owners to adjust the horses diet and in some cases, letting the horse stand in a stable or in a paddock that has thick bedding or soft sand to reduce the pressure on the pedal bone. It is vital for owners to understand that there is no cure for laminitis, so prevention is key to avoiding it. Nevertheless, there is hope, if owners remain vigilant and call in professional help, before it is too late.