Rainbow and Cushing's Disease

Rainbow, our 31-year-old veteran a.k.a Fossil, has had Cushing’s Disease for about five years. Fortunately, to the date of writing, this has not impacted on her quality of life.

What is Cushing's disease?

Its full technical name is Pituitary Pars Intermediary Dysfunction which morphs into the convenient acronym PPID. It is the result of a malfunction of the pituitary gland that is located at the base of the brain. This is the control centre for the secretion of hormones throughout the body. The most common cause of this malfunction is believed to be the growth of a tumor in the pituitary gland. This in turn causes the adrenal glands near the kidneys to produce too much cortisol which affect blood pressure and the general condition of the horse.

It is most prevalent in older horses.

How was Rainbow diagnosed?

One of the earliest symptoms of an equine developing Cushing’s is when they do not shed their winter coat. Their hair continues to grow, it becomes thick and coarse while others around them have got their full glossy summer coats. We noticed this in Rainbow about five years ago and asked our vet to examine her for the disease. This involved a physical examination and the analysis of a blood sample. Both proved positive for old Rainbow and ever since then her condition has been managed successfully with an ongoing course of medication.

Her quality of life has continued apart from the occasional "bad hair day."

The Bad Hair Day—Not the First Nor the Last

By Easter 2019, Rainbow had regrown her coat that we had strip clipped during the warm autumn. Her hair was thick and coarse this year and the weather was warming up quickly. Over the preceding two weeks she had suffered a mild bout of colic. In hindsight we think may have been caused by her getting too warm. And it was the fourth such bout over as many months during a mild winter. It was time for the clippers which I have been banned from using.

On the Saturday, I had arranged to ride out on the forest with a friend while Heather was going to stay at the yard with Rainbow and give her a full clip. That was the plan and my part of it went well.

I helped Heather get Rainbow into the clipping area on the yard. Sorted out the battery powered clippers and then went off for my ride.

When I came back Rainbow was turned out in her paddock happily grazing. From a distance she looked quite smart. It was only when I put Benney away and spoke to Heather that I learnt the full story.

After clipping one side and starting on the other the batteries had gone flat.

The full horror of Rainbow’s bad hair day was revealed when I turned Benney out to join her in the field. What had from a distance looked like a shiny well cut coat was contoured with tram lines and tufty patches. Then on the other side Heather had managed to clip the neck and it is was by the time she reached the shoulder that the batteries ran out of power.

It looked like a combination of Punk and Turkish with spikes and lumps interspersed with strips of severely short hair. Unique would be another way of describing the look.

By Sunday, the batteries were fully charged. The plan was that I was going to go for a hack again while Heather finished clipping Rainbow.

Once again, my part of the plan went well.

When I returned to the yard Rainbow was not in her paddock but in the tie up area for clipping. She was munching quietly on her hay net while Heather stood next to her beaming the broad smile of success. Even in the half light of the barn I could see that Heather with a little help had managed to make Rainbow smart again.

Sometimes the difference between a bad haircut and a good one is three to four weeks. In Rainbow’s case it was only 24 hours.

Further Treatment

To get to the root cause of the mild colic, which Rainbow has had three or four times over the last six months, our vet carried out a worm count and this was slightly higher than normal. The treatment was a dose of a stronger worming paste. The next stage, which take place very soon, is that Rainbow undergoes a scan to eliminate the possibility of any suspicious growths developing in her intestines.