KILLER DISEASE STRIKES THE SHOWING WORLD

A lethal disease is sweeping the world of horse showing. Presently there is no cure and the disease is not fully understood. The disease has been given the acronym ODL. Horse vets are so concerned that, this year, two international conferences have been convened to discuss the problem. Although the disease can strike any horse it seems to affect animals involved in the showing world much more commonly. The symptoms can vary from a quite insidious onset to a sudden attack which leaves the horse in considerable distress and pain, often unable to rise. The organs affected vary but usually involve the gut, liver, kidney and feet. The eyes are affected in the early stages, the affected animals develop a mild opacity of the cornea; giving the eye a dull slightly cloudy appearance. Approximately 20% of cases have to be destroyed and the remainder are usually left crippled for life. As yet no infective organisms, such as bacteria or viruses, have been consistently isolated from affected horses. Horse are being struck down at grass and whilst stabled and in work.

Professor Philip Johnson of the University of Missouri, a pioneer researcher into ODL, comments "Greater than 30 new pharmaceuticals are in various stages of research. However, it will likely take many years before any of these drugs are shown to be useful and safe in horses".

There is an increasing awareness amongst vets and researchers that the incidence of the disease is associated with certain types of feeding and management practices. These can lead to the development of cells within the abdomen which begin to secrete hormones, in a totally unusual and hitherto unsuspected manner. These hormones interact with hormones from the horse's pancreas and change the way the horse's energy metabolism operates. The altered hormone balance is thought to adversely affect the cells lining the blood vessels, leading to impaired blood flow and vasoconstriction. Additionally, affected mares are found to be difficult to get in foal.

A side effect of this hormonal activity is a subtle change in the horse's shape as it develops swellings on the top of the neck, around the loins and tail head and the udder or sheath. These swellings can be very difficult to get rid of. Once these changes have taken place, clinical experience indicates that many horses become metabolic cripples for life. They are unable to handle their food normally and are subject to the devastating effects of ODL. Researchers are becoming increasingly convinced that the predisposing factors to ODL begin early in the horse's life. Professor Johnson states " Management practices that promote the development of (ODL) are likely initiated during the first 10 years of the horse's life".

So, what is ODL and how can you prevent your horse dying from it. Experience of vets involved with the condition indicates that although the disease is devastating in affected horses, in many cases it can be prevented. So what are the feeds and management practices which we should avoid in order to safeguard the horses we love and cherish?

Primarily the secret is to avoid feeds which are high in calories. When fed to horses, and ponies, in excess of their energy needs these feeds start the disease process by making the animal lay down fat. In fact it is the fat cells within the abdomen which secrete the abnormal hormones which upset the horse's metabolism so badly. Coarse mixes, high energy nuts and cubes and straight grains are the danger feeds which lead not only to ODL but osteochondrosis when fed to young growing horses. Instead chose forage feeds, which are high in digestible fibre but low in calories, alfalfa, hay, straw and unmolassed sugar beet are good types of feed to chose.

In addition to commercially available feeds, owners should be aware of the dangers of allowing the horse access to fresh grass, as this can be very high in energy. The secret to managing horses to avoid ODL is to make sure you keep your horse at a condition score of 2½ to 3. That is not so thin that you can see his ribs but so that you can feel them easily when you run your hand along his side. He should not be allowed to carry fatty swellings along his crest or loins or sheath as this immediately puts him at high risk of ODL.

So why is ODL so much more common in show horses ? From the foregoing you should be able to answer this question yourselves. It is because show judges, generally, demand that animals be fat if they are to have a chance of winning a rosette. Robert Eustace FRCVS Director of the Laminitis Clinic opines, "Condition is fat. Show condition is obese. You can make your horse fit and healthy by developing muscle tone through exercise without the need to have him fat. Until show judges and breed societies begin to understand how their predilection for obese show animals is directly responsible for the high incidence of ODL, hundreds of horses will continue to die every year. Intentionally encouraging a horse to develop a disease is cruelty. As exhibitors you should seriously think of boycotting classes judged by people who demand obesity as a prerequisite for success".

So what does ODL stand for - Obesity Dependent Laminitis (also known as Metabolic Syndrome).