Dealing with Cushing's Disease in Senior Horse

An amateur dressage rider's life changes when her senior horse contracts Cushing's disease.
Avatar:
Author:
Publish date:
Social count:
0
An amateur dressage rider's life changes when her senior horse contracts Cushing's disease.
Leslie Doak and Le Cadeau | Photo courtesy of Leslie Doak

Leslie Doak and Le Cadeau | Photo courtesy of Leslie Doak

I am a serial monogamist when it comes to horses. I can only seem to love one at a time. They stay with me through their lives, and I see it as a privilege to care for them as they age, as I do for my senior horse with Cushing's disease. They have invariably cared for me during the arduous process of becoming riding partners. They usually did not hurt me when the opportunities presented. They inexplicably delivered me at X safely, when effective riding technique had departed long before the end of a test. They endured my silly expressions of anger, which should have been directed toward myself. They put up with even sillier new ideas for training, which arrived with regularity but not necessarily effectiveness. Their unconditional acceptance of our relationship was unique in this highly conditional world. Well, maybe there is one condition--food.

My current old man is a 23-year-old French Warmblood, Le Cadeau, which means "the gift," and he truly has been. He was my 40th birthday present to myself and the horse I had worked and saved for. As an amateur with a full-time job, I faced the classic irony: enough money but not enough time. Previously, the inverse irony prevailed: enough time but not enough money. We did some good work together in the first seven or so years. I learned a great deal from him. He was kind, but not easy, just the right mix for learning. On occasion, he was just plain ornery, but there were moments of brilliance that took my breath away. I love arena work and am happy taking good instruction, working toward ideals rather than awards. I do have terrific respect for those who achieve both. We showed some, but neither of us liked it much. Showing takes an inner drive from both the rider and the horse. Sometimes it works if just one or the other has the drive, but it is not likely to work if that drive is missing in both.

Then, one day, he was old. He was turned out on four legs and came back on three. The official diagnosis was a blown tendon. All indications were that it would heal and it did. What I did not know at the time was that horses in the early stages of Cushing's disease sometimes have tendon problems. What I have found in my research may be anecdotal, but the reports are there. It may simply be coincidental rather than causal that old horses have tendon problems and old horses have Cushing's. I am not a veterinarian or a scientist: I just know what we have been through.

After the tendon healing, we went back to work slowly. Had I foreseen the future, I would have been concerned that his coat was a little shaggier in the winter and not so sleek in the summer. I just thought he was being a teenager. He seemed a little ouchy now and then, but I figured that there had to be some degree of permanent damage to that tendon. I simply stopped riding if he seemed off. Then, on a fine November day, we had a lovely ride and completed the post-ride primping. I disconnected the crossties to return him to his stall and he did not want to move. He looked worried and uncomfortable. Finally, gentle prodding and food baiting won. He walked, stiff and sore, to his stall. He had laminitis. I was still naive, but certain that he had not been fed or ridden too much. So, the veterinarian recommended the Dexamethasone suppression test. Naive again, I believed that it was a rule-out test, so I could be assured that this was not Cushing's. Of course, it was.

I have read since, that often horses with Cushing's come down with laminitis in the fall. Without pretending to be an expert on the disease, my understanding is that Cushing's is caused by an enlargement on the pituitary gland, which is responsible for the regulation of hormone production. The pituitary is the master gland. In the fall, the pituitary gland receives information from the pineal gland indicating the changing length of days. Since the pituitary is not functioning correctly in a Cushing's horse, there is a hormonal response (excess, endotoxic) that results in laminitis. So, as the days shorten in the fall, the risk of laminitis rises.

We eliminated all alfalfa and other foods particularly rich in carbohydrates and sugars, as a safeguard against the laminitis. Later, I discovered that any beautiful green hay would cause foot soreness by sundown. My equine vacuum cleaner became a picky eater. He would eat a food especially selected for his well-being for a week or two and then suddenly reject it. The veterinarian prescribed Cyproheptadine which, at the time, came in pill form. It was no challenge for this horse, like most others in my experience, to leave those pills behind in his grain bin. My scientist husband began weighing the prescribed number of Cypro pills on a laboratory scale, then grinding the pills in a coffee grinder and weighing out the white powder which was harder to leave behind than the pills. This was before the anthrax scare, so our only worry was that someone would think we were cocaine dealers.

There was a little side trip on this journey, involving the thyroid. Since the enlargement on the pituitary gland wrecks havoc with the endocrine system, it is not surprising that other glands become involved. My horse tested for hypothyroid, as well. So, the veterinarian prescribed Thyro-L, as well as the Cypro. About a month after we started giving him the thyroid-booster, I took the horse out to longe. He took off at a gallop, fortunately still attached to the line, to me and in a circle, and ran full out for what seemed like 20 minutes. I was afraid he would simply have a heart attack and collapse. When he finally came back to reality and walked for an hour or so to dry the sweat (Cushing's horses have difficulty controlling body temperature), I made a deal with the vet. We pulled him off the thyroid medicine and just allowed the Cypro to work for a month. After that time, a thyroid function test showed that the thyroid had corrected. Apparently, thyroid and Cushing's issues can be very difficult to sort out.

A year went by and, with very expensive corrective shoeing, I thought we were dodging the bullet. Then came November again, and, almost to the day, he had another laminitis flare-up. At the same time, the farrier who had done such a miraculous job with my horse's feet moved away. So, I had the double-whammy: medication that had ceased to be effective and no way to continue the corrective shoeing. Long story short, the veterinarian prescribed Pergolide and the farrier suggested bare feet. Both solutions have worked and are still working. We blew by last November, but another is soon coming up.

I mentioned that Cushing's horses have trouble controlling their body temperature. Las Vegas summers are brutal, especially when the temperature rises over 110 degrees. I did not know that horses pant. They do not loll their tongues like dogs, but breathe rapidly through the nose. Again, I thought he would just collapse, until the veterinarian assured me that it had nothing to do with getting oxygen. It was a cooling behavior and he could do it for as long as he needed to. I gave him a low trace clip, so he would still have protection from sun and insects. Fly sheets have an average life span of 12 hours on this horse. This past summer, my horse added breathing into his waterer to his cooling repertoire and is known to flick water with his muzzle like an elephant to keep his chest wet.

He does lose weight easily, even though his appetite seems good right now. He is rowdy at his stall door at feeding time and competes with his neighbors for who can suck up the most the fastest. His body shape is changing: He is losing muscle mass, looking lumpy on his butt and ribby in motion. He eats but cannot fill in the places that are hollow. I longe and ride lightly, according to the weather and his mood. I like to think this improves his self-esteem: It probably only makes me feel like I am doing something. He still expects a carrot each and every time I pass the refrigerator and paws on the rare occasions that I do not deliver. While he has bouts of depression, they have become less frequent and last no more than a couple of days.

The more recent articles on Cushing's in horses put forth the idea that the disease is much more common in older horses than previously understood. In the late 1970s, my first horse was entering his 20s and his chronic lameness and wet stall led me to ask a veterinarian whether this was commonly age-related. The veterinarian, at that time, never used the term "Cushing's" but did suggest an enlargement on the adrenal gland (well, it is close to the pituitary and does play a role in the excess cortisol production). So, my first horse did not receive the benefits of the human medicines that we now have available. He still lived for many years after his first tendon problems presented, until the Cushing's took over. It is certainly possible that many horses with Cushing's are out there undiagnosed. There are so many different indicators of the disease. One article suggested that all horses with Cushing's will eventually present laminitis, if they live long enough. It is probably time to stop surfing the Internet for articles on Cushing's! We all know where this ends. I am reminded each time I see him that it is all about the journey, not the destination.