Colic is often described as something that “just happens”, but in reality, many cases are linked to everyday management factors. While not all colic can be prevented, understanding what causes colic in horses allows owners to reduce risk and spot problems before they escalate.
This article explains the most common causes of colic in horses, particularly those seen on UK yards, and how routine decisions around feeding, turnout, water, and stress can affect the digestive system.
👉 This article supports the main guide: Signs of colic in horses
Why Horses Are Prone to Colic
Horses have a highly specialised digestive system designed for:
- Continuous grazing
- Constant movement
- Small amounts of food over long periods
Modern management — stabling, hard feeds, restricted turnout — doesn’t always align with this design. Because horses cannot vomit, any disruption to digestion can quickly become painful and dangerous.
1. Sudden Feed Changes
One of the most common causes of colic in horses is rapid dietary change.
This includes:
- Changing hard feed brands
- Increasing or decreasing feed amounts quickly
- Switching hay or haylage without transition
- Sudden access to rich grass
The gut relies on a stable population of bacteria to digest food properly. Sudden changes disrupt this balance, leading to gas build-up, spasms, or impactions.
Best practice:
- Make feed changes gradually over 7–14 days
- Introduce new forage slowly
- Monitor droppings during transitions
2. Dehydration and Reduced Water Intake
Dehydration is a major contributor to impaction colic, especially in winter.
Common reasons horses drink less:
- Cold weather
- Frozen or dirty water buckets
- Unfamiliar water (travel or competitions)
- Illness or stress
When water intake drops, the contents of the gut become drier and harder to move, increasing the risk of blockages.
Practical tips:
- Check buckets daily
- Use slightly warm water in winter
- Add water to feeds
- Monitor drinking habits closely
3. Poor-Quality or Inappropriate Forage
Forage should make up the majority of a horse’s diet, but not all forage supports good gut health.
Problem forage includes:
- Dusty or mouldy hay
- Very coarse, stemmy hay
- Poorly fermented haylage
These can:
- Slow gut movement
- Increase impaction risk
- Irritate the digestive tract
Always inspect forage carefully and change suppliers gradually if needed.
4. Lack of Movement and Excessive Stabling
Movement is essential for gut motility. Horses designed to walk and graze for many hours a day can struggle when confined.
Colic risk increases with:
- Long periods of stabling
- Box rest
- Limited turnout
Even gentle movement helps stimulate digestion.
Helpful strategies:
- Maximise turnout where possible
- Hand-walk if turnout is limited
- Use track systems or multiple hay stations
5. Stress and Routine Changes
Stress has a direct impact on gut function.
Common stress triggers include:
- Yard moves
- Travel
- Competitions
- New horses in the herd
- Changes in routine
Stress can reduce appetite, alter gut motility, and contribute to colic — even in horses that appear calm on the surface.
6. Parasites and Worming Issues
Internal parasites can irritate or damage the digestive tract.
Problems arise from:
- High worm burdens
- Inconsistent worming
- Worm resistance due to over-worming
Modern best practice is worming based on faecal egg counts, reducing unnecessary chemical use while protecting gut health.
7. Dental Problems
Dental issues are an often-overlooked cause of colic.
Poor dentition can lead to:
- Inadequate chewing
- Larger food particles entering the gut
- Increased risk of impactions
Regular dental checks (at least annually) are essential, particularly for older horses.
8. Weather Changes
Sudden weather changes can influence:
- Water intake
- Grazing behaviour
- Stress levels
Cold snaps, heatwaves, and storms are all commonly associated with increased colic cases.
Owners should be extra vigilant during these periods.
How Multiple Factors Combine
Colic rarely has just one cause.
For example:
- Cold weather → less drinking
- Less drinking → dehydration
- Dehydration + coarse hay → impaction colic
Understanding how factors interact helps owners take preventative action early.
👉 For early warning signs, see:Early signs of mild colic in horses and complete list of colic symptoms
What Owners Can Control (and What They Can’t)
You cannot control everything — but you can manage:
- Diet consistency
- Water availability
- Turnout and movement
- Stress reduction
- Routine health care
These factors make a measurable difference to colic risk.
When to Seek Veterinary Advice
If your horse shows:
- Behavioural changes
- Reduced appetite
- Changes in droppings
- Recurrent mild colic episodes
Speak to your vet. Repeated mild colic often indicates an underlying management issue.
👉 For urgent situations, see: When is colic an emergency?
What causes colic in horses
Understanding what causes colic in horses empowers owners to make better daily decisions. While colic can never be eliminated entirely, thoughtful management, consistency, and observation significantly reduce the risk.
Small changes, applied consistently, often have the biggest impact.