Do Horses Get Cold in the Winter or in Rain?

Horses’ bodies begin to grow a double-long winter coat when the days begin shortening, not as a response to colder temperatures. This means that by the time the temperatures actually drop, their coats are already thickening and lengthening. Their coats are double, meaning they grow long guard hairs as well as dense undercoat hairs. The undercoat traps warm air next to the horse’s skin, preventing it from being blown away by wind, or dampened by wind, fog and snow. The guard hairs have a variety of purposes. They trap moisture in the air, keeping it away from the undercoat. A layer of skin oils builds up along them, such that moisture stays away from the skin. In rainy or snowy conditions, the long hairs stick together thanks to this oil, allowing water to run off like a duck’s back. These hairs also keep frost from reaching the undercoat by giving the ice crystals a surface on which to form that is far away from the horse’s skin.. If you pay attention to horses in snow, you will see that they often have a blanket of snow sitting on their back and haunches. This shows how the system of the double coat keeps them warm – their 101-degree-F body is not melting the snow as it lands on them because the hair perfectly insulated them. Finally, the mane and tail are an extra layer of waterproof defense on the neck, and the fine skin of the horse’s dock and thighs where less hair grows.

In addition to external protection against the cold, nature has equipped the horse with an efficient internal heating system. As autumn progresses and winter approaches, grasses and plants get tougher with a higher fiber content. These plants take longer to digest, their components being broken down in the cecum rather than the small intestine. The fermentation process by which these fibers are broken down generates heat, warming the body up. This is why horses tend to seek out more hay in the wintertime.

Is all that to say you should just leave your horse out to the elements because nature has set him up for success? No, it is not. Remember that an old horse in nature is a nine-year-old, and most horses die suffering from starvation or at the hands of a predator well before that. There is a very good reason to not have our horses live the most natural lives possible. However, our care and management of their well-being in captivity should support their nature and how their body was meant to function. 

Winter weather is made up of cold temperatures, wind, and precipitation. Generally speaking, the average healthy adult horse can handle two out of those three conditions at a time. When all three of those conditions are in place, or there are other things going on with the horse’s health, then the horse may need a more radical change in its lifestyle.

Every horse needs the option of some sort of shelter in the wintertime, at least a set of trees for horses in a field or paddock. The best option is a three-sided shelter with the closed side facing into the direction from which the wind blows. If you are interested in designing and constructing such a building, you can look at Building Small Barns, Sheds and Shelters, or Horse Housing.  If having a shelter is not an option (for example, the horse is stabled and goes into a paddock with no shelter for a short time each day, or there are no trees in the pasture), the horse may need to wear a turnout blanket. For information on picking a blanket, see THIS ARTICLE. Regardless, throughout the winter someone needs to check on the horses several times per day. Anyone who lives in a harsh climate knows that the weather can change at the drop of a hat, and with that, the horses’ needs can change equally quickly.

It is also important that all horses have ample access to hay in the winter. Since hay is so important, care must be taken that it stays dry and critter-free. Using slow feeder hay nets  in stalls or Freedom Feeder round bale nets outside can help hay last for longer, and slow down horses who tend to gulp their food quickly. Hay can be stored up on pallets in a barn, and creative use of tarps or jumbo tarps can keep the hay safe from the elements. Depending on his age and activity level, your horse may need other additions to his diet, and to this end, you can learn more in The Horse Nutrition Handbook.

Another very important aspect of winter horse care is access to water. While horses may eat snow, this causes them to burn more calories as their bodies melt the snow in their stomachs – calories that they need to maintain their own body heat. Offering horses tepid water (or at least not icy-cold water) is important to keep them from developing impactions in their gut, especially as they eat more roughage.   

Another thing to watch out for in the wintertime is scratches, a skin disease caused by certain microorganisms living in the soil. When horses stand in mud, the skin on their legs and ankles gets chapped, and the microorganisms begin to take over the skin. The Equiderma line of products is particularly effective in treating scratches and rain rot, another disease that can plague horses in wet conditions.

Horses are amazingly designed to withstand Old Man Winter, but they often need some help in order to maximize their wellbeing during these months. With a bit of diligence and careful attention, your horse can enjoy his winter in comfort, even if you have to brave the elements to ensure it for him.