Q. What causes laminitis in ponies and how can it be prevented and treated?
Laminitis is one of the most painful, crippling diseases of horses, ponies and donkeys. It is inflammation of the tissues that bond the hoof wall to the pedal bone in the horse’s hoof. Laminitis weakens the attachment of the pedal bone inside the hoof capsule, and can result in sinking or rotation of the pedal bone within the hoof. This involves painful tearing of the support structure suspending the pedal bone. Severe laminitis may necessitate humane euthanasia of an affected horse to alleviate suffering.
Laminitis can be diagnosed on clinical signs, and a history of a predisposing event. Most laminitic horses have a typical stance, with their front legs angled forwards and their back legs held underneath the body. This stance takes weight off the toe area, which is usually the most painful and shifts weight to the heels. Laminitic horses usually have hot feet, with a bounding digital pulse, and they are reluctant to walk or pick up their feet. Pain is usually more evident in the front feet. Diagnosis of sinking and rotation is made on radiographs of the feet.
The most common causes of laminitis are grain or lush pasture overload; sequel to infection (for example, a retained placenta, severe enteritis or pneumonia); equine Cushing’s disease or equine metabolic syndrome.
Prevention of laminitis centres on timeous management of the predisposing conditions, particularly Cushing’s disease and equine metabolic syndrome. Both of these conditions are best handled by managing body weight in the affected individuals and maintaining a suitable body condition score. Cushing’s disease can be treated with medication (Pergolide is the drug of choice), but ponies affected by equine metabolic syndrome benefit most from frequent, low-level exercise (unless they already have laminitis) and elimination of high carbohydrate feeds from the diet. Hoof care is very important in predisposed ponies – radiographs of the feet will reveal the position of the pedal bone, and allow the farrier to trim and shoe the foot optimally. It is vital to maintain the normal anatomical position of the pedal bone within the hoof capsule.
Acute laminitis treatment centers on the causative event, for example severe infection or endocrine disorder. While this is being addressed, certain empirical measures can be taken to minimise the risk of laminitis. These include anti-inflammatory drugs like Finadyne or Phenylbutazone, vasodilators like Acepromazine, icing of the foot (special freezable boots), reduction of exercise, and housing in a stall with deep bedding or soft sand. Soft sand allows the horse to angle his pedal bone in the most comfortable position. Polystyrene pads applied to the sole, and reverse shoes can help to redistribute weight off the painful toe. Concentrates are forbidden at this stage.
Dr Robin J. Moore, BVSc, Drakenstein Veterinary Clinic
A. Egg shells are recommended as they contain calcium carbonate, a good source of necessary calcium in the diet. Cuttlefish bones can also be used. If egg shells are used they should be thoroughly boiled first. If the bird is on a good diet of proper pellets, fruit and greens with a little seed, no extra supplements are necessary.
Dr Dorianne Elliott, head veterinarian, Bird and Exotic Animal Hospital, Onderstepoort Veterinary Academic Hospital