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In recent years, we have observed a growing trend of using warm rugs to protect horses during the winter. The fact of housing more horses in open yards or providing winter turnouts during the day, rather than confining them to stables for 23 hours, has undoubtedly played a role in this shift. Frequently, horse owners are concerned that their horses might become wet and/or cold. What factors should be taken into account when exposing your horse to inclement weather?

Many people tend to overlook the fact that a horse’s winter coat is a highly effective natural protection that surpasses even the performance of modern functional jackets. As creatures of the open plains, horses have evolved to thrive in adverse weather conditions, including snow, biting winds, and rain.

The winter coat of a horse consists of two different types of hair: a warming undercoat and an outer coat that is water-repellent and may have hollow fibers in the winter, providing insulation.

The mane crest and tail also serve to divert water away from the particularly sensitive areas of the horse. If you closely observe a “soaking wet” horse, you will notice that the top coat is flattened down, allowing rain to run off the surface. Moisture doesn’t penetrate the skin at all in this state.

When you part the coat, you can see the dry undercoat in the deeper layers, which creates an excellent insulating layer. The outermost layer of fur can even freeze, while the skin underneath remains warm and dry, thanks to the undercoat’s insulating properties.

After a rainy period followed by a temperature drop, the top layer of the coat may become icy, but the undercoat and skin remain dry, warm, and the horse remains in good spirits.

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Simultaneously, the capillary action of the hair carries perspiration away from the skin to the outer layer, allowing it to either run off or evaporate, serving as a cooler rug. Even after a ride where the horse has been sweating, you can observe that, after a mere 15 minutes of leisurely walking, the undercoat close to the skin is already dry, despite the horse still appearing wet on the surface.

Simultaneously, the horse can adjust the angle of its hair depending on the external temperature, regulating heat radiation as needed. When the sun is shining, the hair muscles adjust the hair position to allow for heat dissipation, preventing overheating. On the other hand, in cold weather, the coat lies flat to trap a warming layer of air in the undercoat, providing better insulation than even a down jacket.

Using a warming rug significantly disrupts this remarkable self-regulating mechanism, especially if the horse is also clipped underneath. This results in the horse being consistently either too cold or too warm. Sweat cannot be released sufficiently, and the cooling effect through evaporation, if the horse gets too warm, does not function properly with a rug.

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You just have to monitor throughout the day how frequently we add or remove layers of clothing. Based on the surrounding temperature, we adjust the number of clothing layers we wear to maintain a comfortable body temperature. However, people don’t rush to the stable every hour to change their horse’s rug to match the temperature.

A rug that is warm enough at night is far too warm on a sunny or windless day. And it doesn’t work the other way round either. In the morning and evening hours, you would then need an additional medium-weight blanket. To ensure that the horse maintains the correct body temperature throughout the day, you would need to change the rug multiple times. No one does that.

Furthermore, most horse owners typically blanket their horses with a winter rug in October and remove it sometime in March. This would be equivalent to putting on your clothes in October and taking them off again in March, spending 23 hours a day wearing them during this period, including, of course, the post-exercise sweating. Sounds disgusting? It is – for the horse no less than for us.

Because horses are naturally clean animals and their fur has a dirt-repellent property, akin to a natural lotus effect. Even when a horse’s coat appears dirty on the outside (as owners of grey and piebald horses may know), a horse without a rug will never appear as feces-covered and crusty as a rug might look after a week of wearing.

Moreover, when you use a rug, you create a dark, warm, and humid environment underneath it, which is the ideal breeding ground for skin fungi. To prevent the horses from developing fungal issues, manufacturers often treat blankets with fungicides, making them less than ideal for the horse’s health. Overall, using a horse rug cannot be considered ideal for the horse’s well-being..

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We humans often tend to make assumptions about horses based on our own experiences and needs. What do we do in winter? We tend to layer ourselves with clothing and seek shelter indoors by a warm stove as much as possible. The practice of keeping horses in the stable during past years, shutting all doors and windows to maintain warmth, has led to various health issues, ranging from chronic coughing (due to poor ventilation) to colic (caused by a lack of exercise).

There is a shift in mindset, with a growing realization that horses can be turned out even in inclement weather. The trend towards open yards, paddock trails, and thoughtful exercise management is a positive development. Owners often worry about whether their horses are comfortable and warm, but it’s essential to remember that a horse’s winter coat is a highly effective natural insulation.

A study from Norway, a country known for its harsh winters, examined this topic more closely. When horses (without a rug) are given the choice between being outside or in an (un-) heated stable, they typically prefer to be outside without a rug. Regardless of the weather conditions, the horses spent an average of 50% of their time outside the stable, even during rain and snow. On warm and sunny days, they even chose to be outside almost 90% of the time on average.

The type of horse made a significant difference in their outdoor preferences. Horses with more “blood” (warmbloods, thoroughbreds, and blood-type ponies) spent much less time outdoors than the “robust horse type,” including cold-blooded horses and sturdy ponies. Indeed, the thickness and type of the winter coat play a significant role in a horse’s preference for staying outdoors. Thoroughbreds typically have thinner winter coats, while Icelandic horses, for example, have thick, insulating woolly coats. Horses with thinner or less insulating coats may feel the cold more quickly than those with thicker, more insulating winter coats.

Just like humans, horses have individual variations in their tolerance to cold. Some horses are naturally more cold-resistant, while others may need a bit more protection in chilly weather. Dry cold weather is generally better tolerated by horses, and a simple shelter for protection from wind and precipitation is often sufficient to keep them comfortable. Wet and cold conditions can make horses more likely to seek shelter, especially those that tend to shiver or become uncomfortable in such weather. It’s not necessary to install a heating system in an open yard for horses. Their natural adaptations, such as their winter coats, are usually sufficient for them to withstand cold weather. Absolutely, horses are well-equipped to handle dry, cold weather. Their winter coats and natural adaptations allow them to stay comfortable in these conditions. A windbreak can be highly beneficial for horses during cold, windy weather.

When strong winds displace the undercoat, the heat-retaining properties of the coat’s cushion are compromised. In such conditions, a herd of (wild) horses tends to huddle closely, aligning themselves with their hindquarters facing the wind. They rotate positions from outer to inner, allowing each member to take shelter in the slipstream and preserve warmth. In cases where a group lacks the cohesion to shield each other from the weather, or if a horse is in the turnout alone, you may consider installing windbreaking wooden barriers or windbreak netting as an alternative.

In these areas, it’s common to find your horse comfortably snoozing behind the barrier, feeling relaxed and warm even in strong winds. During rainy weather, horses with thinner winter coats tend to appreciate the shelter of a roof over their heads. Older horses, in particular, may struggle to generate sufficient heat and might lose weight more quickly. In such cases, it might be necessary to use a rug overnight or even consider keeping the horse in the stable during the night. It’s not uncommon to observe horses that stand outside, completely at ease in heavy rain, and many of them even enjoy being in the midst of falling snow. And there’s nothing more delightful for horses than rolling in the snow.

Therefore, before confining your horse to a “warm stable” or covering it with a rug, it’s essential to observe how it reacts and copes with the weather. Providing an adequate amount of roughage, ideally ad libitum or until the horse is satiated, in close-meshed hay nets, is essential as an energy source, along with ensuring wind and rain protection. Consider a “keep warm” solution only if the horse is consistently losing weight, displaying persistent muscle tension, or shivering while on the turnout. However, this is required less frequently than commonly assumed.