Being familiar with the signs that your horse may have Cushings is important, because there are medications and management changes available that can make a huge different in your horse’s quality of life, AND prolong their life.
What is it?
Pituitary pars intermedia dysfunction (PPID; equine Cushing’s disease) is an endocrine disorder that occurs in over 20% of aged horses, ponies, and donkeys, but based on my herd and the horses I hear about through my community, I believe that, anecdotally, that number could very well be higher in Miniature Horses. Currently, of the 15 horses I have who are over 20, six of them have Cushings, and I have three 18 year olds who have been diagnosed as well.
Most horses are over 15 years old when diagnosed, but PPID can occur in younger horses. It is rare in horses less than 10 years old, but not unheard of.
PPID is caused by a benign tumor on the pituitary gland, that affects their hormone production, most notably resulting in an excess production of cortisol, a stress hormone, which can cause all sorts of issues for them.
The process is progressive, so horses will develop more and more symptoms, and catching the early signs and beginning medication will help prolong their active life, by hopefully preventing laminitis and other physical changes.
How is it Diagnosed?
PPID is diagnosed by blood test, performed by your veterinarian. Usually they will run a complete metabolic bloodpanel to check for not just PPID , but also Insulin Resistance and Equine Metabolic Syndrome, because the symptoms can be similar and more information can be gathered to find the right treatment approach for your horse. And even after your horse is diagnosed and is on medication, it’s important to regularly (once a year generally, but check with your vet) recheck their bloodwork so that adjustments can be made as needed to medication dosages – as it is a progressive disease, meds will need to be adjusted to compensate.
Medication
It used to be that a horse who developed Cushings was simply going to deteriorate until they had to be euthanized. The stereotypical “old horse” appearance, with a long shaggy coat, protruding backbone and ribs, and head hanging with dull eyes is a textbook example of advanced, unmanaged PPID.
Today, we are lucky to have an extremely effective treatment available in the drug Prascend (pergolide). Prascend is available in a tablet form, that is easy to split for smaller dosages and can be given in feed, or dissolved into water and syringed into their mouth. It is extremely effective in most cases, with a nearly magical seeming improvement. I’ve seen horses who appear 10 years younger in just a few short weeks of medication, horses who return to soundness after years of struggling with laminitis, and a huge change in their demeanor, going from “old” to full of energy.
There are a few horses who have side effects of appetite loss and lethargy on Prascend, and may need to have a gradually increased dose, and I have heard of rare cases where a horse couldn’t adjust to the meds and it wasn’t a viable treatment, but the benefits of the medication make it worth making every effort to try. I have not personally had any issues with Prascend, only benefits!
They do need to be on Prascend daily for the rest of their life – it’s not a cure, but it is an effective management.
Management
The medication does need to work in conjunction with management changes. Horses with PPID do much better on a diet that is very low in sugars and carbohydrates.
Feed hay that has been tested to have a low NCS (nonstructural carbohydrates – which turn to sugars during digestion), or soak your hay to lower the starch content prior to feeding. As horses with Cushings are also usually aged, I have had very good luck feeding soaked cubes – both for the tested low sugar content and the ease of chewing and digestibility.
If you’re feeding a concentrate, choose an extruded feed that is, again, low in sugar and starch content. Whole grains can be dangerous, as they’re high in starch that is converted to sugar during digestion. Most feed companies will produce a senior feed that is safe for horses with metabolic issues.
Be very cautious about green grass with horses that are diagnosed with Cushings, especially if laminitis has been one of their symptoms in the past.
If your horse has had laminitis as a result of their Cushings, then frequent, knowledgeable farrier care will be a huge part of their management as well. Keeping their angles comfortable for them makes a huge difference. Depending on their current comfort level, my Cushings/laminitis horses will be trimmed every 2-6 weeks.
Once they’re on medication, their coat usually improves and begins to shed again, but initially you may need to help them out by clipping in the summertime to help prevent overheating.
Symptoms to Watch For
Because PPID is a hormonal imbalance, it can manifest in a LOT of different symptoms. I’m going to share the ones that I’ve seen most commonly in my horses, and heard from those in my community, but if you have a horse who is over 15 and you have any sort of suspicion that “something” is off with them, then it’s definitely worth talking to your vet about testing for Cushings.
Weight Loss – by far the number one sign I’ve noticed in my horses is that I’m struggling to keep weight on them. I’ve had their teeth done, I’ve upped their feed, and nothing seems to help. Diagnosis with PPID and treatment with Prascend and they pick right up again!
Laminitis – If your horse develops laminitis with no changes in their management or environment, especially in the winter, then definitely test them for PPID and other metabolic issues.
Lethargy/Not Themselves/Seeming “Old” – Sometimes this is a symptom I only realized in retrospect. We thought Image was just finally calming down in his old age, and then he started on Prascend and within 2 weeks was the same impatient, pawing, high energy pain in the butt we all knew and loved! Other times it’s been one of the primary reasons I tested – something just seemed “off” too me.
Long, Curly Hair Coat, or Not Shedding – Horses than don’t lose their winter coat even in the summer time, or have very long, curly hair coat, I’ve noticed especially on their legs.
Other Symptoms:
Regional Fat Deposits
Loss of Muscle over Topline
Increased Water Consumption/Urination
Skin Conditions & Other Infections
I recently learned that Recurrent Corneal Ulcers, Rounded Abdomen and Tendon Laxity are also symptoms – all of which I had seen in my horses prior to treatment, but never connected them as a symptom of Cushings!
Basically, if you noticed anything out of the ordinary, especially if your horse is over the age of 15, then it’s worth having the vet run the bloodwork, as the meds can make such a difference in their quality of life.
Pictured is Pride, before and after being on Prascend to manage his PPID. In the first photo, note his long, curly hair coat (especially on his legs), his feet showing strong evidence of recurrent episodes of laminitis (he was quite sore and reluctant to move), and tendon laxity, particularly on his hind legs. Contrasted with the second photo, with his shiny black coat, normal looking legs and feet – and sound enough to enjoy a drive, as you can see from the harness marks! He’d been carefully managed in his previous home – diagnosis of PPID, treatment with Prascend and more frequent farrier care were the only changes we made. The photos are 9 months apart. He was 27 years old in these photos, he’s 29 now and still in excellent health on Prascend.
