VALLEY — Horses and other animals thrive in winter weather. When we see them we may be concerned for them but they are more comfortable than we realize. Animals who spend their time outdoors adjust to cold winter weather in more than one way. The acclimation to cold weather can be both quick or long term. The goal is to save body heat.
The quickest response a horse, or any animal, can make to cold weather is to change their habits. First, instead of moving around and being highly active they will reduce activity to only what is necessary. Next they will look for shelter from the cold and wind. Shelter may be behind trees, a hill, the barn or by a group of animals coming together like a football huddle. Being together can reduce heat loss.
Horses will stand with their head away from the wind. With their tail toward the wind and down they lose less body heat. Animals will also stop moving around and foraging to conserve energy. Ok, then why do we see horses running around in cold weather? The movement will increase muscle contractions which generates heat internally. Yes, some winter running is just for fun! Shivering and other muscle activity generates body heat as well.
For long term exposure to cold the animals take a longer term approach to acclimation. They develop a heavy winter hair coat. This hair coat is an excellent insulator. Cold weather will cause the hair to stand up, trapping and retaining body heat. The outside of the hair coat may be cool but the insulation holds the heat in. That’s why you may see animals with snow or frost down their back in the morning before the sun melts it. A sheep’s wool coat does the same thing; the curly wool traps warm air in and keeps cold air out.
The outside temperature also has a hand in whether the animals are comfortable or not. Animals have a “Thermal Neutral Zone.” This is a temperature range where internal body heat production remains consistent and the animal is comfortable. If the outside temperature gets outside the thermal neutral zone the animal will need to increase or decrease body temperature. Animals have a “Lower Critical Temperature” (LCT). Once the outside temperature reaches the LCT animals internal body heat production increases.
For horses the LCT is around 22°F for young horses and 32°F for mature animals. For cattle the LCT is around 18°F. When the temperature reaches these levels, we can help by providing shelter or additional feed. A shed is most often a three-sided building with a roof. Shelter can conserve up to 20 percent of a horse’s body heat.
Feed also plays a role in keeping animals warm. Grain provides a quick boost of internal heat production. It is quickly digested and the heat production is complete. Hay on the other hand takes longer to digest. The microbes in the digestive tract have to work longer to break down the fibers, so they generate heat longer. This is one reason feeding in the evening is a good idea. As the nights are colder the animals keep generating internal heat longer keeping them warm.
Animals have a built in mechanism for surviving in cold climates. They grow a second or heavier hair coat. People have clothes, coats, hats, gloves and boots to help do the same thing. Another interesting fact is that animals that grow in a colder climate are usually a larger body size than animals in a warmer climate.
If you have questions, you can also call the Colorado State University Extension, San Luis Valley Area Office at 719-852-7381, email us at [email protected] or contact your local Veterinarian.
Extension programs are available to all without discrimination, Colorado State University Extension, U.S. Department of Agriculture and Colorado counties cooperating.