12/12/2024
I have addressed this problem so many times in the field and in my group that I still don’t quite know why it has taken so long to actually do a short article on F***l Water Syndrome aka “FWS”.
FWS typically presents in horses as an excessive amount of thin brown liquid being ejected from a horse’s a**s. This is different from diarrhea because it doesn’t have any f***l matter contained in the liquid. The horse’s manure may be on the soft side or may be perfectly formed.
In most cases FWS isn’t debilitating to the horse but it is messy and can coat their butts and legs with nasty smelling and irritating liquid. It is especially difficult during the cold winter months as you can see from the photo I used. The fluid clumps on fur and freezes while the cold temperatures make it difficult if not impossible to clean.
Obviously FWS is a gastro-intestinal issue but most owners miss the mark when treating FWS. Owners will throw expensive supplements at the problem and the symptoms will persist. I know this from personal experience with my mare, Flair. That poor mare had about 32 different supplements thrown at her and nothing worked.
Probiotics, prebiotics, biosponge, ulcer treatments, gut supplements and anything else I tried wouldn’t clear it up. Nothing ever even slowed it down.
Then while attending an equine nutrition clinic I was having a cocktail with one of the more well known equine nutrition PhDs and I mentioned my frustration to her. Of course she had the answer!
Just so everyone knows, it’s not that I’m really smart but I hang out with really smart people!
In the overwhelming majority of cases FWS is being caused by a mild case of a condition known as Right Dorsal Colitis. I got the full monty clinical explanation, and as I would do in any conversation with an extremely bright, lovely woman who is twenty years younger I sat at the edge of my chair in rapt attention while understanding none of it but all I needed to know was that it is a condition similar to Irritable Bowel Syndrome in humans.
IBS is something that most people in my age range (somewhere between classic and Jurassic) are familiar with. The cure for both conditions is simple: add easily digestible fiber. I began taking a tablespoon of psyllium each day and my IBS cleared up almost immediately.
Right Dorsal Colitis can become very serious and require clinical intervention in some cases. In severe cases FWS is accompanied by lethargy, weight loss, lack of appetite and colic. I am NOT a vet so you should discuss any concerns that you have with your vet and follow their treatment advice.
Many times RDC is caused by coarse hay. Mature, coarse hay is very high in fiber and can be difficult to process in the gut causing some inflammation resulting in the watery fountain of stench emanating from your horse’s butt.
My own experience with FWS is very much like what I hear from others. The FWS shows up in the fall when the horses are off grass and on hay. Whenever I get different hay. My horses are both easy keepers and metabolic so I feed mostly very mature low NSC grass hay ensuring that I am dealing with FWS for most of the year. Quite often you will find that it is worse during the winter and the simple explanation is that they are eating more hay which attenuates the problem.
The dietary treatment for both conditions is to replace some (or all) of the forage with a complete feed enabling the gut to recover by offering some easily digestible fiber.
You can also try using some psyllium but it’s expensive and it typically requires a large dose.
My personal go to and the advice that I have offered to hundreds of people as a first treatment is to simply add a pound of hay stretcher pellets per day to the horse’s normal diet and this usually clears it up. If the FWS doesn’t clear up in a few days I increase it to two pounds per day.
Any genuine complete feed will work as long as the crude fiber is over 20% and the fat level is low. I typically choose to use hay stretcher because it is very high in fiber, usually over 25% and it is not heavily fortified nor high in calories so I don’t really need to make huge adjustments in their diets. I simply toss a cup or two on top of their normal ration and call it a day.
For a 1,000 pound horse two pounds per day should offer relief of the symptoms but if two pounds of hay stretcher doesn’t change things it’s probably time to try something else and at this point all bets are off. Psyllium would be my next step along with a gut supplement.
It is almost never a lack of probiotics unless the horse had recently been on a course of antibiotics.
The long term solution is to feed better hay. If you can find some nice, soft second cutting grass hay it would go a long way towards drying things up.
There are a number of downsides to feeding better hay. Cost and availability are at the top of the list. Then there’s the horse. Second cutting hay isn’t the best choice for easy keepers or insulin resistant horses so this option has its limits.
Many times FWS is linked to insulin resistant horses as a sure sign that they are insulin resistant. The conditions are not related except that most IR horses are on j***y, low starch, low calorie hay.
Please allow me to head off the naysayers and negative comments. This is not by any means a sure fire cure for FWS. It is, however, a very inexpensive treatment as a first go to attempt and it does work in most cases. If not, then try all the whiz bang supplements that probably won’t work either.
In short, if you have a horse with a squirty butt go buy a bag of cheap hay stretcher pellets and run some through the horse. If it works, you got off cheap, if not at least you know something that isn’t going to work.
As a final reminder and a more serious tone, if the FWS persists and the hay stretcher doesn’t work I would strongly encourage you to please consult your veterinarian and have all the appropriate diagnostics done.
Thank you for reading this article.
I am retired and write blog articles to try to make horse owner's lives easier and horse's lives better.
If you found this article to be helpful my horses would be very grateful if you would consider buying some hay for them by going to:
https://buymeacoffee.com/jimthefeedguy
Of course your contributions are not required, nor expected but all are very much appreciated.
Cheers!
