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How do horses stay warm?

Have you ever noticed on those blistery cold days, when you dread going outside, that your horses seem fresh and content?

Have you ever noticed on those blistery cold days, when you dread going outside, that your horses seem fresh and content?

Are they really enjoying the cold weather as much as they appear? Unquestionably, yes! How can they be so happy in the playing outside in the snow when we cringe at the thought of going outside? It’s simple, they are made for it!

A horse begins to prepare for winter just after the summer solstice (June 22nd ish) when his body recognizes the shortening of the days. This triggers hormones that shift his coat into a growth phase, pushing the summer hairs out of the follicles as the winter hair grows.

This explains why you might have noticed that your horse appears to shed in late-summer.

Horses exposed only to warm weather conditions in this late June-October period may only grow a light winter coat, while horses exposed to colder conditions will grow a longer, thicker coat.

The longer, thicker coats trap more dirt and oils against the skin, resulting in a layer of insulation that helps to keep the horse warm and dry.

The coarse, fluffy winter coat stands up (rather than lying flat like a sleek summer coat) and traps a layer of warm air close to the body.

This process is called piloerection. The blood vessels in the skin constrict from the cold and the hair shafts stand up on end.

This winter coat is amazingly functional.

It is a mixture of thick, dense hairs and long, coarse “guard” hairs. The coat lays in a downward (toward the ground) tilt encouraging rain and snow to glide down and off the horse. This discourages the moisture from saturating the horse and causing him to get chilled from being damp in the cold. It’s like a waterproof jacket!

When the temperature drops, the horse’s appetite increases. An increased consumption of food is the body’s way of putting on a few extra pounds of winter “insulation” in the form of fat.

This light layer of body fat under the skin is the horse’s next level of defense against the winter cold.

Internally, digestion is the primary warming process. The digestion of fibre (hay) in the cecum and large intestine results in the production of heat. This internal furnace keeps the horse warm in cold weather.

Like any furnace, it requires something to run on and in the case of your horse, its hay and lots of it!! In the bitter cold your horse should have a constant supply of good quality hay to keep his furnace going.

A cold horse may start to shiver. Shivering is a very effective way of raising the horse’s internal body temperature. The rapid tensing and releasing of the large muscle groups (which occurs 10-20 times per second) quickly warms the horse. Because it requires a great deal of energy stores, shivering is only a short term warming remedy. Horses should not be left to shiver for extended periods of time.

Even the way horse’s respiratory systems are designed aid in keeping them warm.

The long, spiral shaped tube (called a turbinate) that inhaled air travels through in the nose, helps to warm the air before it reaches the lungs. This prevents heat loss that could potentially cool the horse’s core.

Aren’t they amazing? Our horses are designed to stay warm in extreme temperatures, but there are things we can do to help.

Proving shelter from the wind, snow and rain is one of the basic horse keeping essentials. Large numbers of horses kept together need multiple shelters and/or windbreaks. Trees provide shade in summer but are of little value in winter.

Providing a constant supply of good quality hay is important. Feeding multiple times daily or free choice are both options.

Be aware that in the coldest of days, your horse will drink less than usual.

Partially because the sensation of ‘thirst’ is less in winter and partially because drinking cold water when it’s cold outside isn’t necessarily pleasant.

I like to feed our outside horses warm beet pulp all winter; I simply soak beet pulp in really hot water until it has fully expanded. I mix loose salt into the beet pulp. This increases the water intake for the horse (because beet pulp is wet) and the salt encourages the horses to drink.

Impaction colic in winter is common because of the decreased water consumption.

Beware of using a winter blanket just because you want to help your horse stay warm. Blanketing an unclipped horse can actually cause him to be colder as the hair is unable to stand up under the winter blanket. Either the blanket needs to be substantially warm or don’t bother. The exception to the blanketing unclipped horses is in cases of freezing rain, a waterproof sheet will prevent the horse becoming wet, but so would a nicely bedded shelter! Obviously, clipped horses should always be blanketed outside in cold weather.

Until next time, happy horse keeping!

Shelly Graham is a local rider, trainer, horse breeder and Equine Canada certified coach.