Understanding Your Horse’s Digestive System
Warning Signs Every Owner Must Know
Your horse’s gut is remarkable — and remarkably fragile. Here’s how to read the signals before they become emergencies.
Your horse’s digestive system is nothing short of extraordinary — and extraordinarily fragile. Unlike dogs, cats, or even humans, horses are designed to trickle-feed for up to 18 hours a day. They have a relatively small stomach, a hindgut that ferments fibre, and a digestive tract stretching over 30 metres. It’s a system built for a very specific lifestyle, and when we disrupt it — intentionally or not — the consequences can range from mild discomfort to a life-threatening emergency.
The good news? Your horse can’t hide his discomfort the way some animals can. If you know what you’re looking for, he’ll tell you — through his posture, his eyes, his gut sounds, and his behaviour — long before a problem becomes critical.
This post walks you through the essential warning signs of digestive distress, what they might mean, and exactly what to do. Because understanding your horse’s gut could one day save his life.
Why the Horse’s Digestive System Is So Vulnerable
Before we look at warning signs, it helps to understand why horses are so prone to digestive upset in the first place. Several anatomical quirks stack the odds against them:
- Horses cannot vomit. The cardiac sphincter is so strong that once food enters the stomach, it only moves forward — making blockages and gas build-up especially dangerous.
- The stomach is small (roughly 8–15 litres) relative to body size, designed for small, frequent meals — not large infrequent ones.
- The hindgut houses a delicate microbial ecosystem. Sudden dietary changes, stress, or antibiotics can devastate this balance within hours.
- The colon has several tight bends where impactions love to form, particularly at the pelvic flexure.
- The intestines can move — sections can twist, telescope into each other, or become displaced. All of these are surgical emergencies that can develop within hours.
“The horses in my care over 45 years have taught me one thing above all: they always tell you. The question is whether we’re listening.”
The Warning Signs: What to Watch For
Warning signs fall into three urgency levels. Learn to distinguish them — the difference matters enormously when you’re deciding whether to call your vet immediately or monitor overnight.
Emergency Signs — Call Your Vet Immediately
Do not wait · Do not give pain relief until you’ve spoken to your vet — it can mask symptoms your vet needs to assess
- Violent, uncontrollable rolling or thrashingA horse in severe abdominal pain will throw himself down repeatedly, often regardless of the surface. There’s a desperate, frantic quality to it — very different from a normal roll.
- Persistent, repetitive pawing at the groundIf it’s repetitive and doesn’t stop, combined with other signs, treat it seriously. Your horse is communicating discomfort.
- Repeatedly looking back at the flankYour horse is telling you exactly where it hurts. Repeated flank-watching combined with pawing or rolling = colic until proven otherwise.
- Elevated heart rate over 60 bpm at restNormal resting heart rate is 28–44 bpm. A rate above 60 bpm is a red flag. Above 80 bpm suggests severe pain or shock. Learn to take your horse’s heart rate — it’s one of the most useful emergency skills you can have.
- Pale, white, or bluish gums / CRT over 2 secondsHealthy gums are salmon pink. Press and release — colour should return within 2 seconds. Pale or blue gums with slow refill = circulatory compromise. This is an emergency.
- Complete absence of gut sounds in all four quadrantsAll four quadrants should have sounds. Silence on all sides for 10+ minutes is not normal and suggests intestinal paralysis or severe impaction.
- Distended, drum-tight abdomenA tight, drum-like belly — particularly on the right flank — suggests gas colic or displacement. This can turn surgical fast.
- Sweating without exercise or heatPatchy cold sweat, especially around the flanks and neck, is a pain response. Combined with other signs, do not delay.
- Lying down and unable or unwilling to riseWeakness combined with reluctance to stand can indicate severe pain, cardiovascular compromise, or a twisted gut.
Watch Closely — Contact Your Vet if Signs Persist or Worsen
Check every 15–30 minutes · Call your vet if not resolved within 1–2 hours
- Mild, intermittent discomfort — occasional pawing, shifting weight, brief lying downNote the time it started. Mild colic that doesn’t resolve within 1–2 hours warrants a vet call.
- Reduced or absent gut sounds on one side onlySome variation is normal, but silence on one side combined with other signs warrants attention.
- Significantly reduced manure output over 12–24 hoursKnow what’s normal for your horse. A meaningful decrease in droppings may signal an impaction beginning to form.
- Loose, watery, or mucus-coated droppings (persistent)Occasional loose droppings aren’t unusual, but persistent loose or mucus-coated manure can indicate hindgut inflammation or infection.
- Refusing feed or leaving more than half of a mealHorses rarely refuse food without reason. Even leaving part of a feed is worth noting. More than one refused meal warrants investigation.
- Dull, depressed, or withdrawn demeanour — “not himself”You know your horse. If he seems quiet, uninterested in his environment, or not himself — trust that instinct.
- Teeth grinding (bruxism)Can indicate gastric ulcers, especially in horses who also show discomfort after feeding, reluctance to work, or girthing issues.
- Excessive, repeated yawningOften overlooked, but repeated yawning can signal gastric discomfort or ulcers — particularly in stabled horses.
Monitor & Investigate — Subtle Signs That Deserve Attention
These quiet signals appear over days or weeks — easy to miss, but important to catch early
- Weight loss despite adequate feedingConsider gastric ulcers, hindgut dysbiosis, parasite burden, or dental issues affecting digestion and nutrient absorption.
- Pot-bellied appearance with poor topline, especially in young horsesA pendulous belly combined with a thin topline can indicate heavy parasite burden affecting nutrient absorption.
- Dull coat and generally poor conditionChronic digestive inefficiency means poor nutrient absorption. The coat often shows it before anything else does.
- Pinned ears, biting, or aggression around feeding timeSome horses become defensive at feed time because eating hurts. Gastric ulcers are a very common culprit.
- Reluctance to work — especially lateral movements, collection, or transitionsUlcer pain is often worse when a horse bends or engages the core. Many horses labelled “difficult” have undiagnosed gastric ulcers.
- Sand in manure (float fresh droppings in a bucket of water)If sand settles at the bottom, your horse has sand accumulation in the gut — a significant colic risk, especially in sandy paddocks.
- Significant changes in drinking habitsDrinking much more or less than usual can indicate gut imbalance. Adequate hydration is critical for preventing impaction colic.
Your First Response: What to Do in the First 20 Minutes
If you suspect colic or digestive distress, here’s your immediate action plan. Work through these steps in order before you pick up the phone — your vet will want all of this information.
⚡ First 20 Minutes — Action Plan
- 1Remove all feed immediately. No hay, water, or treats until you’ve assessed the situation.
- 2Check vital signs: heart rate (normal 28–44 bpm), respiratory rate (normal 12–20 breaths/min), gum colour and CRT, temperature (normal 37–38.5°C / 99–101.5°F).
- 3Listen to gut sounds in all four quadrants — upper and lower, both sides. Note what you hear (or don’t hear).
- 4Check manure: when did your horse last pass droppings? How much, and what did they look like?
- 5Keep your horse calm. Hand-walk if he is mildly uncomfortable and wants to roll. For severe pain, do NOT force walking — call your vet first.
- 6Do NOT give Bute or Banamine without vet guidance first. Pain is diagnostic information your vet needs.
- 7Call your vet with all your observations ready: heart rate, gum colour, gut sounds, last manure, symptom timeline, and any recent changes to feed or routine.
Free Download: Horse Digestive Health Warning Signs Checklist
Print this quick-reference checklist and keep it in your feed room, horse float, or first aid kit. Includes emergency vitals, a gut sounds guide, and a symptom tracker to share with your vet.
Download Your Free Checklist →Prevention: Setting Your Horse Up for Digestive Health
Understanding warning signs is the reactive half of the equation. Prevention is the proactive half — and it’s where 45 years of experience tells me the biggest gains are made.
- ◆Maximise forage timeHorses should have forage available for at least 16–18 hours a day. Long gaps without hay dramatically increase gastric ulcer risk and disrupt hindgut motility.
- ◆Introduce feed changes graduallyAny change to hay, grain, or pasture should happen over a minimum of 7–10 days to allow the hindgut microbiome to adjust safely.
- ◆Maintain a targeted parasite management programmeWork with your vet to design a programme based on faecal egg counts, not calendar-based dosing. Strategic deworming is more effective and reduces resistance.
- ◆Ensure access to fresh water at all timesDehydration is the leading cause of impaction colic. In cold weather, horses often drink less — consider a water heater or offering warm water.
- ◆Keep feeding times consistentThe horse’s gut runs on routine. Even a 2-hour delay in feeding increases cortisol and disrupts gastric acid balance.
- ◆Feed small, frequent concentrate mealsIf your horse requires hard feed, split it into at least two — ideally three — meals, and always feed hay before concentrates to buffer gastric acid.
- ◆Schedule regular dental checks (every 6–12 months)Poor dental health means incomplete chewing, which leads to larger fibre particles reaching the hindgut — increasing fermentation disruption and impaction risk.
You don’t need a veterinary degree to be a vigilant horse owner. You need to know your horse’s baseline — what’s normal for him in terms of gut sounds, droppings, appetite, water intake, and behaviour — and you need to take the quiet signals seriously before they become emergencies.
Build the habit of a quick daily check — gums, gut sounds, manure, attitude — and you’ll catch problems early, every time. Stay curious, stay observant, and trust your instincts. When something feels off with your horse — it usually is.
