Dehydration is one of the most underestimated health risks in horses. It does not only occur during hot summer months — it is equally common in winter when water intake drops due to cold temperatures.
Even mild dehydration can affect:
- Gut motility
- Performance
- Recovery
- Thermoregulation
- Colic risk
Severe dehydration is a veterinary emergency.
This guide explains how to recognise early signs, assess hydration status properly, and prevent avoidable complications.
Why Hydration Is Critical
A horse’s body is approximately 60–70% water.
Water is essential for:
- Circulation
- Digestive movement
- Electrolyte balance
- Joint lubrication
- Temperature control
- Cellular function
Reduced water intake affects the digestive tract first — increasing the risk of impaction colic.
Why Dehydration Is Common in the UK
Summer Risks
- Increased sweating and fluid loss
- Travel and competition stress
- Heat reducing appetite
Winter Risks
- Cold water discouraging drinking
- Frozen troughs limiting access
- Reduced thirst response
- Increased hay intake without added moisture
Winter dehydration is often silent and easily missed.
Early Signs of Dehydration
Subtle signs appear before severe symptoms.
1. Reduced Water Intake
Know your horse’s normal intake.
Average adult horse drinks:
- 20–40 litres per day
- More if in work or warm weather
A sudden reduction is a red flag.
2. Dry or Reduced Droppings
Droppings may become:
- Smaller
- Harder
- Less frequent
Dry manure often precedes impaction colic.
3. Mild Lethargy
A mildly dehydrated horse may appear:
- Quiet
- Less responsive
- Slightly dull
Hydration directly affects energy levels.
4. Changes in Skin Elasticity
Perform a skin pinch test:
- Gently pinch skin on the neck
- Release
- Normal: snaps back immediately
- Delayed return: possible dehydration
Note: This test is less reliable in older horses.
5. Dry or Tacky Gums
Lift the upper lip.
Healthy gums should be:
- Moist
- Pale pink
Dry, sticky, or darkened gums indicate concern.
Moderate to Severe Signs (Urgent)
Seek veterinary attention if you observe:
- Elevated heart rate
- Sunken eyes
- Weakness
- Prolonged skin tenting
- No droppings
- Depression
- Thick saliva
Severe dehydration can become life-threatening quickly.
Capillary Refill Time (CRT)
Press your finger against the gum until it turns pale.
Release and count seconds until pink returns.
- Normal: under 2 seconds
- Delayed refill: possible dehydration or circulatory compromise
CRT is especially important in suspected colic cases.
Horses at Higher Risk
Monitor closely if your horse is:
- In regular work or competition
- Travelling long distances
- Senior
- Experiencing diarrhoea
- On dry forage only
- Living with dental issues
- Recovering from illness
Monitoring should always be proactive.
Preventing Dehydration
1. Ensure Constant Access to Clean Water
Check daily for:
- Frozen troughs
- Algae build-up
- Blocked drinkers or valves
Clean water encourages drinking.
2. Offer Slightly Warm Water in Winter
Providing lukewarm water in cold weather can significantly increase intake.
Horses typically prefer water between 7–20°C. Ice-cold water discourages drinking.
3. Use Electrolytes During Heavy Work
When sweating heavily:
- Replace electrolytes
- Encourage drinking
- Monitor recovery
Electrolytes support hydration but never replace water.
4. Soak Feed Where Appropriate
Adding water to feeds such as:
- Beet pulp
- Fibre feeds
Helps increase fluid intake safely — especially useful in winter or during travel.
5. Monitor After Travel
Travel stress can reduce drinking.
- Offer water immediately on arrival
- Check droppings over the next 24 hours
The Link Between Hydration and Colic
Dehydration slows gut movement.
Reduced gut motility increases the risk of impaction.
Many colic cases have dehydration as a contributing factor — maintaining hydration significantly reduces risk.
When to Call the Vet
Seek immediate advice if your horse:
- Has not been drinking for an extended period
- Produces no droppings
- Shows elevated heart rate
- Appears persistently lethargic
- Displays signs of colic
Do not attempt to force water intake without professional guidance.
The Core Principle
Hydration is not seasonal — it must be monitored year-round.
Know your horse’s normal:
- Drinking habits
- Dropping frequency
- Gum moisture
- Energy levels
Small changes matter.
Water is the most important nutrient in your horse’s diet — protect it accordingly.
Knowledge Hub: https://jsm-equestrian-supplies.co.uk/knowledge-hub/
Category: https://jsm-equestrian-supplies.co.uk/category/horse-health/
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