ASK THE EXPERT.
NOT JUST AN ‘OLD PONY’ DISEASE STUDIES SHOW THAT HORSES DEVELOP EQUINE CUSHING’S DISEASE ANY TIME AFTER THE AGE OF 10, WHICH MEANS THAT MANY DRESSAGE HORSES PERFORMING TODAY COULD BE AT RISK OF THIS POTENTIALLY DEBILITATING CONDITION. DR MARCUS BENNETT MRCVS ADDRESSES THE IMPORTANCE OF SPOTTING THE SIGNS OF THE DISEASE EARLY, AND WHAT YOU CAN DO IF YOU SUSPECT YOUR HORSE MAY BE SHOWING SYMPTOMS.
Q
What causes Equine Cushing’s disease? Equine Cushing’s disease – or more correctly termed Pituitary Pars Intermedia Dysfunction (PPID) – can occur in any horse or pony. It occurs when the control mechanism for the pituitary gland fails, and the gland produces abnormally high hormone levels (see diagram below). There is no gender or breed disposition, but it does become more common with age.
PITUITARY GLAND
NORMAL DOPAMINE PRODUCED BY THE HYPOTHALMUS REGULATES THE PITUITARY GLAND
REDUCED DOPAMINE PRODUCED BY THE HYPOTHALMUS SO PITUITARY GLAND ACTIVITY IS UNCONTROLLED
NORMAL HORMONE PRODUCTION BY PITUATARY GLAND
INCREASED HORMONE PRODUCTION BY OVERACTIVE PITUATARY GLAND
CLINICALLY WELL HORSE
SIGNS OF EQUINE CUSHING’S DISEASE
70 // Issue 7 2021 // BRITISH DRESSAGE
Q
What are the tell-tale signs to look for? Gait and the appearance of the hooves Laminitis is the most life-threatening symptom caused by Cushing’s disease. Although the severe signs of laminitis are well recognised, research shows that the early and moderate signs are still under-recognised. One of the early signs of laminitis can be divergent hoof rings; this is where the hoof rings are closer together at the toe than at the heels. An easy-to-follow checklist which may help you pick up the early signs of laminitis in your horse can be downloaded from CareAboutCushings.com/how-to-spot-it Athletic performance and energy levels Equine Cushing’s disease is known to cause lethargy which can manifest itself in several ways. In dressage this symptom could be seen as a lack-lustre performance, or reduced impulsion. Appearance Equine Cushing’s disease can cause muscle wastage and changes in where fat is deposited. These changes will have a gradual onset and can include the development of a pot belly or cresty neck, loss of topline, a dimpled appearance to the muscle over the
rump, and the development of fat pads over the eye area. In addition to this, Equine Cushing’s disease can cause unusual sweat patterns and coat changes such as a late or partial shed, or the appearance of long guard hairs on the belly. Water troughs and wet bedding Increased drinking and urination can indicate the presence of Cushing’s disease, and this is most commonly noticed by owners when the amount of wet bedding increases, their horses are spotted drinking from unusual containers or their horse’s water trough is needing to be re lled ore fre uently Vet visits Struggling to get an infection under control (e.g. a high worm burden, a foot abscess, a corneal ulcer or mud fever) can be a sign of Cushing’s. This is because Equine Cushing’s disease is known to suppress the immune syste a ing it ore di cult for t e orse to g t o infections It’s also important to recognise that many of the symptoms of Cushing’s can have a slow and insidious onset and can sometimes be confused with the signs of aging. This is
