Equine athletes can reach peak performance well into their teens
and may excel as schoolmasters into their twenties.
Older Horses Rocking their Golden Years
Horses are living longer than ever before, largely as a result of improved wellness care, regular exercise, better nutrition and medical management when body parts start wearing out. For the most part horses have adapted well to a human oriented life style and it’s not uncommon to see them athletically active, still teaching humans, well into their 20’s. However, no mammal is designed to live forever and there are often debts to be paid for the privilege of a long life. For horses, one of these debts can be a messed up metabolism in the form of overproduction of the hormone ACTH from the pituitary gland. The disease process that results from this overactivity is commonly called Cushing’s disease, but more accurately, PPID = pituitary pars intermedia dysfunction. Clinical signs of PPID include hirsutism (persistent long hair coat that doesn’t shed normally) loss of muscle mass, laminitis and a general predisposition to infection. Recent studies have shown that equine PPID is different from human Cushiing’s disease but may share a closer etiology to Parkinson’s disease. As with many age related illnesses in all animals, there is no cure. Fortunately, effects of this metabolic mess up can be controlled with daily medication and management geared to helping maintain normal body function. Payment of this age related debt comes with both a monetary and a management cost, but the good news is that it doesn’t need to interfere with the continued well being or athletic performance of the horse.
The drug of choice for treatment of PPID is pergolide mesylate (Prascend). This drug is in a class of drugs called dopamine agonists (an important relationship). It was developed to treat Parkinson’s disease in humans and its effectiveness is well documented for treatment of PPID in horses. Along with dietary management, appropriate trace mineral supplementation, regular parasite control, dental and hoof care, it helps keep afflicted horses active and competitive well into their “golden years”.
Good drug, Bad drug? Pergolide, what’s not to like??
As far as the horse with PPID is concerned, pergolide is definitely a “good” drug, however according to the predominant ruling bodies of equine sports competition (national, USEF and international, FEI) it is labeled a “bad” drug. Wait, what? Why is that, you might ask. Remember that bit about pergolide being in a class of drugs called dopamine agonists? Well, dopamine agonist drugs fall into the category of potential performance enhancing, aka “bad” drugs according to equine sport regulators. Therefore, pergolide is banned from use in athletes at sanctioned competitive events. For those showing horses that happen to have PPID, this conflict of interest is problematic for entering either USEF or FEI sanctioned competitions. Unfortunately the ruling on this particular drug poses a clear conflict of interest between advocating for the well being of the animal versus regulation of the sport.
So, your older horse is at his competitive best but he needs daily pergolide to stay that way, what’s an owner/rider/trainer to do? As of December 2018 the USEF allows a horse on pergolide to compete as long as a Therapeutic Exemption Form (TUE) has been completed and approved prior to the competition. The TUE report requires veterinary records including laboratory findings that support a diagnosis of PPID, it must be submitted along with a Medication Report Form (MRF) for review by the USEF. The review process may take upwards of 30 days, so plan ahead. Once approved, the Therapeutic Exemption (TUE) will be honored for 3 years. For horses competing under FEI rules, pergolide remains a banned substance without exceptions. A horse must be taken off the drug during FEI sanctioned competition (see specific time frames in the FEI rulebook).
From our veterinary perspective, disallowing a medication that effectively treats a complicated metabolic and endocrine imbalance is not in the horses best interest. We applaud the USEF for recognizing this fact and taking action to make exceptions for pergolide use in the competition setting. At the moment it appears that the FEI is taking cues from human medicine where health “care” takes a back seat to political power struggles. However, as with the democratic process in general, you who are members of the “club” do have a say. If those with horses in this predicament make their concerns heard loud, clear and often, perhaps the FEI “powers that be” will see fit to deal with this issue in a fashion that puts the well being of the horse as their highest priority. In the meantime, be aware of the rules and.....
Whoop, whoop! Go you senior ponies, go!