As horse owners some of us are guilty of thinking they can judge how hot or cold their horse is. Here are some classic examples of how we choose and change rugs significantly in the winter months:


  1. If you feel cold yourself! – Not accurate! Staying warm is far easier for a horse than staying cool, and it is very unlikely horses will feel cold at the same temperatures humans do.
  2. How warm your horse feels – a horse’s core temperature can be drastically different from the skin temperature.
  3. Checking the weather forecast! – Horses can adapt to much colder temperatures, the forecast is therefore not that important. However, wind speed and rainfall have much greater effect, as a wet horse will lose heat at a much faster rate.


Horses have evolved to have effective methods of maintaining a safe core temperature. This means they are naturally equipped for colder temperatures, and do not need as much help staying warm as you might think.

In the wild, horses are very good at regulating their own body temperature. They must maintain their core temperature at 37-38°C or important chemical reactions inside the body stop functioning properly, potentially doing damage to the horse.

The caecum (one of a horse’s digestive organs) is around a metre long, can hold 60+ litres in volume, and essentially acts as a large built-in heating system fuelled by food. The more hay or grass it eats, the more heat is produced. This system allows horses to deal with colder temperatures by eating more and fuelling this heater, meaning it is important that horses have sufficient access to food in colder temperatures.

There are multiple other methods horses have which help them adapt to both warmer and colder temperatures which we’re sure you have seen:

Warming up when too cold:

  • Digesting fibre to increase the heat produced internally.
  • Shivering – heat is produced by the rapid movement of the muscles.
  • Like goose bumps in humans, horses can make their body hair stand upright in the cold. This is called piloerection, and it increases the insulation capabilities of the coat, conserving heat.
  • When the horse is cold, it can make blood vessels nearer the skin get smaller. This is called vasoconstriction, and it keeps more of the warm blood away from the skin and nearer the core, restricting the amount of heat lost from the skin surface.

Cooling down when too hot:

  • The opposite of vasoconstriction (above) is called vasodilation: when the horse is too hot, blood vessels widen so more warm blood can travel nearer the surface of the skin, meaning more heat can be radiated away.
  • Sweating – the liquid sweat evaporating from the skin’s surface draws heat away, cooling the skin down.
  • Panting – breathing harder and faster cools the body by allowing more warm, moist air to be removed from the body, and cold air to be inhaled.


Disadvantages to using too many rugs on your horse:

-          Rubbing and pressure points, particularly with ill-fitting rugs and on shoulders and withers.

-          Fungal and bacterial infections under the rug.

-          Injuries and entanglement.

-          Wet rugs can sometimes be worse than no rug, as they can increase heat loss by being a cold wet surface and they do not allow the horse to raise its hair for warmth.

-          Horses need vitamin D from UV light, and if the skin is too covered it can lead to deficiency.