Free Fecal Water syndrome (FFW) is a condition in which horses produce normal feces, but before, during, or after defecation, free water runs out of the anus. Unlike a true, infectious diarrhea, there appears to be no direct health concerns associated with FFW. However, there are some indirect effects. The watery feces can cause skin irritation as it continuously runs down the hind limbs. During the winter months, the tail may be constantly wet and is at risk for frostbite. In summer, it can attract more flies to the horse. It becomes a management issue for the owner that must be addressed.
There are some horses that are at greater risk of developing this syndrome, such as geldings and Paints. These horses often fall further down the social hierarchy and tend to have more anxiety. In addition, horses recovering from severe colitis (infection of the large intestine) may also be predisposed.
It is proposed that the hindgut of horses with FFW has a change in motility. An increased motility, strong gut contractions, and/or inflammation, all impair the ability of the gut to absorb water.
In order to narrow down the contributing factors, your vet will ask some historical questions about your horse and its diet, such as:
Age – Older horses are more prone to this issue.
Social hierarchy within the herd – FFW can be more of an issue with submissive horses near the bottom of the pecking order, but not necessarily. These horses may be stressed, often being the last to eat at the feeder, left with poorer quality hay.
Diet, supplements – Has there been a recent change from pasture to dry hay, which could have altered the bacterial population in the hindgut due to increased fiber length? We often see more of these cases in the winter, when horses are fed dry hay exclusively.
Dental issues – Is poor dentition causing poor digestion of feed?
Deworming – Has the horse been treated with an effective dewormer in the fall?
Diagnostics for Free Fecal Water Syndrome
If there is no improvement with some diet or social changes, your vet may advise some additional diagnostics, such as:
Bloodwork – Complete Blood Count (CBC) and Biochemistry profile. This can help rule out infectious causes of diarrhea and inflammatory bowel disease, which would show elevations in white blood cell counts and inflammatory proteins.
Fecal Egg Count – A fecal sample can be analyzed in the clinic to detect high worm burdens.
Cushing’s disease test - An endocrine (metabolic) disease of older horses could be implicated in certain unresponsive cases. Positive Cushing’s horses often have impaired immune systems, which can delay recovery efforts for FFW.
Rectal examination/ultrasound – May reveal intestinal inflammation or cancer.
Gastric endoscope – in rare circumstances, a stomach ulcer has been associated with FFW.
Nutrition and Treatment
Horses with Free Fecal Water need access to good quality forage (hay), so they can eat frequently throughout the day. Some horses respond well if the hay is changed to chaff, or chopped hay. Others require hay pellets or hay cube mashes exclusively in order to prevent the issue.
For some horses, especially those with poor teeth, feeding a hay cube mash daily can help. Adding wet pure pysllium husk fiber and salt can improve the effectiveness of the mash. Pysllium is the active ingredient in Metamucil, used to improve bowel regularity in humans. There are equine specific psyllium products, available at your feedmill or tack shop, which are designed to be palatable and effective. With respect to salt in the mash, start with ½ TBSP of table salt per day and then increase it up to 2 TBSP daily if needed. Some horses don’t like their mash too salty.
The starch (grain) in their ration should be kept to a minimum, with only 1 gram per kilogram of body weight per meal. For a 450 Kg horse, that’s only 450 grams (1 pound) of grain per meal, which should only be fed to active horses whom would lose body condition otherwise.
Adding a probiotic, such as Equine Choice, available at the vet clinic, can help improve hindgut digestion.
Your veterinarian may also recommend using a product called Bio-Sponge (Platinum Animal Health), to aid in the management of FFW. It is a smectite clay product, formerly know as montmorillonite clay. It has the ability to adsorb large amounts of water. It is available in powdered form or paste syringes. It can be given up to 7 days at the start of treatment for FFW to help aid gastrointestinal function.
A fecal transplant can be helpful in chronic, unresponsive cases. Your veterinarian will need to perform the procedure by collecting feces from another healthy horse, with low parasite burden. The feces is then mixed with water and fiber pellets and administered using a nasogastric tube.