Digestion

Loose Manure & Excess Fecal Water in Horses: Causes & What to Check

Written by Ben Nedas Reviewed by Dr Rosemary Waring

Quick answer

What horse owners need to know

Loose manure, true diarrhea and excess fecal water are not the same thing. A horse with free fecal water may pass normally formed manure alongside separate liquid, whereas diarrhea involves manure losing its normal form and becoming soft or watery.

Temporary soft manure can occur with changes in pasture, feed, travel or stress, but persistent or recurrent changes deserve investigation. Acute watery diarrhea can be serious in horses because significant fluid and electrolyte losses can occur quickly.

Start by looking at the whole horse: appetite, attitude, hydration, temperature, abdominal comfort, recent feed or pasture changes, medication, parasite control and whether the manure itself is loose or simply accompanied by excess water.

Start with the horse

Understanding what you're seeing

What you may notice

Manure changes can look very different from horse to horse.

You may notice:

• Softer-than-normal manure that still has some shape
• Poorly formed or “cow-pat” manure
• Separate brown liquid passed before, during or after otherwise formed manure
• Water running down the hind legs or tail
• Intermittent changes that seem linked to pasture, travel, competition or feed changes
• More frequent manure than usual
• Stronger odor or increased gas
• A horse that soils its tail or hindquarters more than normal

It is useful to distinguish between genuinely loose or watery manure and free fecal water. In free fecal water syndrome, the horse may continue producing normally formed fecal balls but passes additional liquid separately.

Keep a record of when the change happens, how long it lasts, what the horse has been eating and whether anything else has changed in appetite, behavior, weight or performance.

Common causes

There is no single cause of loose manure or excess fecal water in horses.

Possible contributing factors include:

• A recent change in hay, pasture or concentrate feed
• Lush or rapidly changing pasture
• High concentrate or rapidly fermentable carbohydrate intake
• Stress associated with travel, competition, changes in routine or herd dynamics
• Antibiotic or other medication use
• Parasite burden
• Dental problems that affect how forage is chewed
• Sand or soil ingestion
• Inflammatory or other gastrointestinal disease
• Infectious causes of diarrhea
• Individual sensitivity to a particular forage or dietary ingredient

Free fecal water syndrome remains poorly understood. Veterinary references describe its cause as uncertain, although diet, social stress, dentition and other gastrointestinal factors have all been investigated.

True diarrhea has a much wider range of possible causes and can include infectious disease, inflammation, medications, toxins and serious intestinal disorders. It should not automatically be treated as a simple feeding problem.

What should you check first?

Start by asking what has changed.

1. Is the manure actually loose?
Check whether the feces themselves have lost their normal form, or whether normally formed manure is being passed with separate liquid.

2. How is the horse otherwise?
Look at appetite, water intake, attitude, temperature, abdominal comfort and normal activity.

3. Has the diet changed?
Review new hay, pasture access, feed quantities, supplements, concentrate meals and any recent change in forage source.

4. Has pasture changed?
Rapid grass growth and changes in pasture carbohydrate content may alter hindgut fermentation.

5. Has the horse travelled or experienced stress?
Transport, competition, veterinary visits and changes in social environment can temporarily affect fecal consistency.

6. Review forage and concentrate balance.
Consider whether the horse is receiving sufficient forage and whether concentrate meals are larger or more starch-rich than necessary.

7. Review dental and parasite management.
Poor chewing and parasite burden should be considered in horses with persistent digestive changes.

8. Review medications.
Antibiotics and some other medications can alter the gastrointestinal environment.

If the problem is persistent, recurrent or associated with other changes such as weight loss or poor appetite, involve your veterinarian rather than repeatedly changing supplements or feeds without establishing the likely cause.

Feeding & management steps

Management depends on the underlying cause, so there is no universal feeding fix.

Useful principles include:

• Keep forage intake consistent wherever possible
• Avoid abrupt changes in feed or forage
• Introduce new feeds gradually
• Review the amount and type of concentrate being fed
• Split larger concentrate feeds into smaller meals
• Ensure constant access to clean, fresh water
• Review pasture changes when manure problems appear seasonally
• Maintain an appropriate parasite-control program with veterinary guidance
• Keep dental care up to date
• Reduce avoidable stress around feeding, turnout and transport
• Record manure consistency alongside diet and management changes

For horses with free fecal water, veterinary sources report that some individuals respond to changes in forage type or presentation, but no single feeding strategy works for every horse.

Making several dietary changes at once can make it difficult to identify what actually helped. Where the horse is otherwise well, controlled changes made one at a time are usually more informative.

When to contact your veterinarian

Contact your veterinarian promptly if your horse develops acute or profuse watery diarrhea, appears unwell, develops a fever, shows signs of colic, stops eating, becomes depressed or weak, appears dehydrated, or has blood in the manure.

Persistent or repeatedly recurring diarrhea also warrants veterinary investigation, even if the horse otherwise appears relatively well.

Adult horses can lose substantial amounts of fluid and electrolytes through severe diarrhea in a short period of time. True diarrhea should therefore be treated differently from occasional soft manure or free fecal water.

Persistent excess fecal water, weight loss, recurrent abdominal discomfort or a significant change from your horse’s normal manure pattern also deserves investigation to rule out dental, parasitic, inflammatory, infectious or other gastrointestinal causes.

The digestive connection

Where digestion fits

The horse’s hindgut contains a large and complex microbial population responsible for fermenting material that has not been digested earlier in the digestive tract.

What arrives in the hindgut therefore matters.

When large amounts of rapidly fermentable carbohydrate reach the cecum and colon, microbial fermentation and acid production can increase. Changes in diet, forage and substrate availability can alter the hindgut environment and may be reflected in gas production, fecal consistency and other digestive changes.

This does not mean that every horse with loose manure has hindgut acidosis or dysbiosis. Loose manure has many possible causes.

However, where dietary fermentation is part of the problem, management should consider both what the horse is being fed and how effectively that diet is being digested before it reaches the hindgut.

This is why good forage management, sensible concentrate feeding and support for upstream digestion can form complementary parts of a digestive-management program.

EquiNectar research

What EquiNectar research tells us about gastrointestinal health

EquiNectar has been evaluated in horses with a range of gastrointestinal problems, although it has not been established as a treatment for diarrhea or free fecal water syndrome.

A veterinary field study followed 34 horses with clinically diagnosed gastrointestinal conditions during two months of EquiNectar use. Excess fecal water was among the presenting problems included in the study.

Across the complete study population, 82% of horses showed measurable improvement and clinical signs completely resolved in 47%.

Separate EquiNectar research in performance horses has also measured changes in the hindgut environment. Fecal pH increased during supplementation, providing evidence that supporting digestion earlier in the gastrointestinal tract can alter measurable conditions downstream.

These findings support further investigation of digestive-enzyme supplementation as part of gastrointestinal management, but they do not demonstrate that EquiNectar will resolve every case of loose manure or excess fecal water.

34 horses Veterinary field study involving diagnosed gastrointestinal conditions

82% Showed measurable improvement across the complete study population

47% Complete clinical resolution across the complete study population

What this research does — and doesn't — tell us

The 34-horse study was a retrospective veterinary field study involving horses with several different gastrointestinal diagnoses. It was not a randomized, blinded, placebo-controlled trial specifically investigating loose manure or free fecal water syndrome.

The 82% improvement and 47% resolution figures refer to the study population as a whole and should not be interpreted as success rates specifically for horses with excess fecal water.

The results are encouraging and provide real-world evidence relevant to gastrointestinal health, but they do not establish EquiNectar as a treatment for diarrhea, free fecal water syndrome or any other disease.

EquiNectar is a nutritional digestive supplement. Persistent or clinically significant gastrointestinal signs should be investigated by a veterinarian.

Where EquiNectar fits

Supporting digestion as part of good management

EquiNectar is designed to support digestion rather than treat diarrhea or free fecal water syndrome.

Its Enzyme Rich Malt Extract provides naturally occurring digestive enzyme activities that help break down components of feed and forage earlier in the digestive process.

By improving upstream digestion, EquiNectar can change the dietary material available for fermentation in the hindgut. This makes it particularly relevant where diet and hindgut fermentation are thought to be contributing to digestive inconsistency.

It should be used alongside good management: appropriate forage, sensible concentrate feeding, gradual diet changes, clean water, dental care, parasite control and veterinary investigation where needed.

For horses with persistent loose manure or excess fecal water, establishing the likely cause remains the priority.

Explore EquiNectar

Common questions

Frequently asked questions

What is the difference between loose manure and free fecal water in horses?

Loose manure has lost some of its normal shape or consistency. In free fecal water syndrome, a horse typically continues to pass formed feces but also passes separate liquid before, during or after defecation. Free fecal water is therefore different from true diarrhea.

Can grass cause loose manure in horses?

Yes. Some horses develop softer manure when introduced to lush pasture or when pasture conditions change rapidly. This may settle as the horse adapts, but persistent changes, diarrhea or other signs of illness should be investigated.

Can stress cause loose manure?

Temporary soft manure can occur around travel, competition, veterinary visits or other stressful events. Stress may alter gastrointestinal motility and the hindgut environment. Recurrent or persistent manure changes should not automatically be attributed to stress without considering other causes.

When is loose manure in a horse an emergency?

Profuse watery diarrhea, fever, colic signs, loss of appetite, depression, weakness, dehydration or blood in the manure warrant prompt veterinary attention. Adult horses can lose large amounts of fluid and electrolytes through severe diarrhea.

What should I feed a horse with excess fecal water?

There is no single diet proven to resolve free fecal water syndrome in every horse. Start with a veterinary health check and review forage quality, concentrate intake, recent dietary changes and overall ration balance. Some horses respond to changes in forage type or presentation, but changes should be made carefully and preferably one at a time.

Can EquiNectar help a horse with loose manure?

EquiNectar is a digestive supplement rather than a treatment for diarrhea or free fecal water syndrome. It supports the breakdown of feed and forage earlier in digestion and may be relevant where hindgut fermentation and dietary management are part of the problem. Veterinary EquiNectar research has included horses presenting with excess fecal water, but the available study does not provide a specific success rate for that subgroup.