A horses thermoneutral zone (TNZ) is the air temperature range in which horses expend no energy to maintain normal body temperatures of 99° to 101° F. The lower critical temperature (LCT) is the lowest temperature in the TNZ, below which horses increase metabolic rates and expend energy to maintain normal body temperature. Research suggests healthy, adult horses have a wide LCT, from 41° F for horses in mild climates to 5° F in natural-coated, un-clipped horses adapted to colder temperatures.
Factors influencing a given horse's TNZ include; ambient air temperature, wind, sunlight, moisture and air temperature that the horse is acclimated to. We are all familiar with the incredible winter coats horses grow. Thick coats provide a tremendous insulation factor. Wind and moisture, in the form of rain or melted snow are common factors influencing a given horses TNZ. Keep in mind that young, thin and older horses are less cold tolerant.
Cold Weather Management Recommendations:
- A waterproof blanket provides great protection for horses living outside all the time. Remove the blanket every few days for cleaning to minimize risk for skin fungal infections. Be prepared to rotate blankets, replace wet blankets with clean dry blankets.
- Shelter from snow, wind and winter rain is recommended. This allows horses to stay dry which helps them stay warm. Barns or run in sheds with raised floors are optimal.
- Gradually acclimate horses to extreme cold temperatures. Full acclimation takes about 21 days.
- Research confirms cold weather increases dietary energy requirements. Feeding free choice, good quality hay, is a simple method providing additional digestible energy in mature, idle horses experiencing ambient air temperatures below their LCT.
- Maintain free choice access to non-frozen water. Many horses don't desire to drink "ice-cold" water. There are numerous types of water heaters capable of maintaining drinking water slightly above freezing temperature.
- Ensure horses receive adequate vitamin/mineral supplementation, including salt! Allow free choice access or add one tablespoon daily to the horses grain mix. Feed plain, white, granular livestock salt with no mineral added. Top-dress appropriate vitamin/mineral supplement to the grain serving.
Simply said, the following three things will decrease cold stress in your horse.
1. Provide areas for horses to get out of the wind chill.
2. Keep your horse dry.
3. Increase dietary energy to provide more calories for the horse to stay warm.
And the bottom line; blanketing can be an important management tool to reduce cold stress in horses experiencing winter weather extremes!
