4 August 2023

PSSM – An unexploded bomb in the equine world?

PSSM – An unexploded bomb in the equine world?

This article has been written by a good friend of Chapelstone – a woman passionate about equine health. What she has discovered about PSSM may provide answers for so many horse owners.

Hello everyone. I thought I’d give an update on Rupert because I truly think what I’ve found out is the tip of a massive, massive iceberg affecting enormous numbers of horses.

In a nutshell, I got Rupert last July from someone I knew. I bought him because he had previously lived at my old home alongside my beloved Jack and I was in desperate need of a companion for him. I knew Rupert was quirky and I knew that it would be very unlikely that I’d ride him as I’d seen his previous rider manage his quirks very well but she is a much more experienced and braver rider than I am. There was a suggestion of ulcers but he had not been scoped. And, for as long as I’ve known him he has been a bad cribber and wind sucker but for all the time I knew him/knew of him he was living out with other horses and had very sympathetic owners so the immediate modification of his living arrangements wasn’t going to elicit much of a change.

ANYWAY, Rupert arrived and he was clearly a bit stressed, quite reactive and at times rather strange, for want of a better word. He was a hand-reared orphan foal from the Coolmore Stud i.e his mother was a foster mare for the racehorses and he’d been immediately taken away and put into a barn with other poor babies. This history was used to explain all his behaviours and of course, will have played a massive part in some of the things he did.

However, as we went into cooler weather he became more and more angry and defensive. Increasingly he would flatten his ears on my approach, he would not initiate any contact (which he had to some extent during the summer) and if you tried to stroke him he would bite out at you. I carried on trying to give him space to decompress etc and enriched the environment etc but we really were not progressing. I figured that there had to be a pain element to such behaviour and embarked upon many thousands of pounds of veterinary investigations – Back Xrays, Neck Xrays, multiple blood tests, scans, and weekly body workers (which was fairly disastrous as he would not tolerate touch), a full diet overhaul (already a diet that was sensitive to the suggestion of ulcers but then going through the Equibiome test and making the recommended changes) and then a course of injected Omeprazole to see if the ulcers were behind the behaviours. I was not prepared to put him through the stress of a scope as he was becoming increasingly dangerous to handle and I knew that starvation, travel and then the scope were way too much for him.

There was a moderate change to the way he held himself after the Omeprazole and by this time he was being rugged (about 250g rugs) even though none of my other horses had ever needed rugging, they have full access to three shelters, ad-lib forage etc.

But the angry defensive and dangerous behaviours kept going on, to the point where I was getting frightened of being around him.

By the start of this year, I was beginning to make my peace with the idea that he may never be right and that perhaps euthanasia was to be considered. He was so unhappy and angry all the time and it was extremely distressing to see because NOTHING was working.

A very knowledgeable friend suggested I test him for PSSM and when it became increasingly clear that as the weather was improving so was his mood and tolerance my vet agreed to do the hair test on Rupert.

Long story short – he was tested and came up positive for PSSM 2 PX variant. I am utterly delighted to have some answers at last.

Where I believe it is a real problem is that over the past few weeks I’ve made contact with owners groups and the prevalence of PSSM 1 and 2 throughout breeding lines is shocking. My own vet has come across a number of local cases since we got Rupert’s results because he then tried on a few other horses that were demonstrating problematic behaviours.

I am going to attach a link to the info about it – this can show signs when ridden, it can show up through behaviour, it can show up alongside all sorts of other conditions.

I truly think PSSM is an unexploded bomb in the horse world and that so many behavioural cases may find that PSSM lies at the heart of it….

Here’s the link to some more information – truly hope this might be of use to some of you


Bottom line is that horses are not shits or twats or bad….they are trying to deal with the situations they find themselves in and reacting to things that may not be immediately obvious at all. It’s taken months and months of digging and at times misery to get to the bottom of Rupert’s stuff and this is just the beginning of our journey together. I have been so lucky with the wonderful people who worked with us who always gave him the benefit of the doubt and knew that eventually, we’d find the key to unlocking the puzzle of this lovely boy and his defensiveness.