Faecal Water Syndrome in Horses

What is Equine Faecal Water Syndrome? Faecal Water Syndrome (FWS) refers to the passing of excess free liquid before, during or after the passing of droppings. It can also happen independently of defecation, where no physical droppings are passed. The droppings themselves may appear quite normally formed or may also be quite loose. In some horses, the issue is persistent whilst in others it can be seasonal or sporadic and entirely random.

It is unfortunately common that Faecal Water Syndrome results in horses having dirty tails and hindlegs that require frequent grooming and washing. In the warmer months, the issue may subsequently attract flies. In severe cases or with sensitive horses, it can lead to irritation and dermatitis on the hindlegs and buttocks, whilst some start to object behaviourally to being washed so often. In mares there is the increased risk of contamination to the vulva, leading to infection or reduced fertility in breeding stock.

What causes Faecal Water Syndrome in horses? The exact cause is often hard to determine but it generally indicates that something somewhere is irritating the digestive tract, or it is simply not working correctly.

In older horses it can be a result of reduced fibre intake when they are no longer able to manage long stem forages such as hay. Fibre has an excellent water carrying capacity but insufficient chewing of hay, or simply an insufficient fibre intake, will reduce this capacity requiring excess water to be expelled separately - only so much fluid can be filtered out and expelled via urination.

Some very coarse hays with a high indigestible fibre content, akin to straw, can also have the same effect as they do not carry water effectively.

The most common irritants otherwise are feeds high in sugar and starch often containing molasses or cereals and cereal by-products. Soya and GM products may also pose an issue, as can any harsh chemicals added to feeds during growth, harvest or production. Some horses with feed intolerances may show this through developing Faecal Water Syndrome rather than a skin reaction. Some medications, a worm burden or administering a wormer may also be a trigger. Stressed horses can also pass loose droppings though this is unlikely to be true Faecal Water Syndrome.

Typically, horses on a forage based diet may be at lower risk of developing Faecal Water Syndrome but ryegrass-based forages and haylage can also be triggers, especially as the latter can be quite acidic due to the fermentation process.

In some cases, the trigger may be a more serious underlying health condition such as Inflammatory Bowel Disease or Hindgut Acidosis.

How do you treat a horse with Faecal Water Syndrome? With these horses it is always best to try and establish the route cause as without doing so, any amount of intervention or treatment may fail.

For older horses it can be a simple case of swapping their forage for an easier to chew alternative such as HayCare or for younger horses, swapping to hay over haylage. It is also essential to avoid any long gaps without forage as this can lower pH throughout the digestive tract and cause irritation.

Any feeds containing unsuitable and potentially irritating ingredients should be removed with a focus on increasing forage variety in the diet. Feeding a more varied forage diet is known to support a more diverse range of hindgut microbes which is beneficial for digestion and also immune response.

Encourage the grazing of hedgerows and verges where free from poisonous plants and overseed with a diverse seed mix (free from ryegrass) to produce more variety in the paddock. Simple System's Natural Grazing Mix is a blend created specifically for horse pasture and is ideal for overseeding.

Use a different forage type for your chop and your pellet feed making use of acid buffering and low sugar lucerne where possible. Certified organic feeds further ensure minimal exposure to irritating chemicals. Sainfoin is particularly useful as it is thought to support the hindgut microbes thanks to its condensed tannin content.

PuraBeet and Instant Linseed may offer soothing support; beet-pulp is high in soluble fibre which adds bulk to the diet and is highly digestible to avoid over-working a stressed digestive tract.

Linseed forms a mucilage like gel when digested to physically coat the lining of the digestive tract and its anti-inflammatory properties can promote healing. Both these also aid the passage of feed.

Eclipse Recovery is rich in the metabolites of fermentation to support gut function, fibre digestion and immune response.

Horses with Faecal Water Syndrome are also at risk of losing dissolved salts and becoming dehydrated. It is important to provide free access to a plain salt source or consider adding Summer Salt to their feed or water to aid rehydration. Alternatively place a Salt Lick Tub in the stable or out in the field. Make sure that plain, unsalted water is also always freely available, and they are drinking adequately.

If the condition persists or worsens despite changes to management and feeding, or you become concerned for your horse’s health and welfare, it is always wise to consult with your vet.

For a free Feed Plan tailored to your horse's individual requirements please contact our equine nutrition team on 01728 604 008. Alternatively complete our advice request form.