The thermoneutral zone is the temperature range where the body can maintain its core temperature with little to no extra energy expenditure. For humans, this range is quite narrow at 21–28 °C, but for horses it’s much broader at 5–25 °C.

This difference means we should avoid rugging horses based on how cold we feel. Over-rugging can lead to serious health issues, including metabolic problems and thermoregulatory dysfunction.

Tips for Choosing a Winter Rug Weight

• Clipped horses may need a heavier gram fill to stay comfortable.

• Remember: horses warm themselves more easily than they cool down under a rug. If unsure, choose a lighter rug.
  

• Check your horse regularly to make sure they are neither too hot nor too cold.

• Consider your horse’s age and natural ability to stay warm.
  

• As a general guide, rugging is usually appropriate when temperatures drop below 5–10 °C, but always adjust for your horse’s individual needs.

• Always ensure rugs are waterproof. A wet rug is worse than no rug at all.

This is an indicative guide only. Always take into account factors such as wind chill, your horse’s age, weight, and condition.