People also believed a weekly bran mash would keep the bowels moving; however, we now understand that this is achieved in a less than desirable way. The passage of loose manure results from disrupting the delicate balance of bacteria in the horse’s cecum and large colon. As a result, feeding infrequent bran mashes is no longer recommended for horses. Additionally, feeding bran frequently can cause problems with the calcium-phosphorus balance in some horses’ rations.

A better approach to help keep your horse warm in winter is to feed plenty of forage. Those same bacteria in your horse’s cecum and large intestine that become disrupted by sudden diet changes are responsible for breaking down complex carbohydrates. Forages provide large amounts of complex carbohydrates.

Microbial breakdown of complex carbohydrate is a process of fermentation. Fermentation in the cecum and large colon occurs in the absence of oxygen, and this anaerobic degradation of organic compounds results in the release of volatile fatty acids (VFAs). These VFAs are absorbed by the horse and converted to useable forms of energy.

Without the bacteria, yeasts, and other organisms involved in this fermentation process, horses wouldn’t be able to utilize the complex carbohydrates within forages. This is because, like other mammals, horses don’t themselves create the enzyme necessary to break apart the bonds holding complex carbohydrates together.

While it’s possible for a horse at maintenance who’s consuming an all-forage diet to meet approximately 80% of his daily calorie requirement from the fermentation of complex carbohydrates (the remaining calorie requirements comes from simple carbohydrates and fats in the forage), it’s not a 100% efficient process. Some of the energy released when complex carbohydrates are broken apart is lost as heat and helps to maintain body temperature. Essentially, the heat produced via fermentation of forage in the horse’s hindgut is like having an internal furnace.

Feeding plenty of forage during cold weather will help your horse maintain core body temperature. Increasing hay intake in winter will do a much better job of helping your horse stay warm than feeding a warm mash. However, feeding dry hay does not address the main benefit of the wet mash, which is increased water intake. One way to achieve both internal heat production from forage fermentation and increased water intake is to feed soaked hay pellets or beet pulp.

Both hay pellets and beet pulp provide sources of complex carbohydrate that require fermentation. If your horse is only fed hay, feeding soaked hay pellets might be the better choice if these soaked meals are not fed every day. Because the pellets are closer in nutritional composition to the hay you’re already feeding than beet pulp, there should be less risk of digestive disruption if the hay pellets are fed infrequently. Keep in mind, though, that your hay and the hay pellets will have nutritional differences, so a risk still exists. However, you would be reducing that risk as much as possible. If your horse actually needs extra calories (beet pulp provides more calories per pound than hay), and you will feed these meals daily, then beet pulp might be the better solution.

Soaked hay pellets fed with a little salt will provide complex carbohydrates for fermentation, water for hydration, and the salt will help to stimulate thirst in the future. Maximizing forage intake is the best way to help your horse stay warm from the inside out this winter, and adding water to meals will help ensure he stays hydrated. Certainly, if it makes you feel better, using hot water to make your soaked meal isn’t detrimental. Just make sure that it is not scalding when you feed it.