To rug or not to rug? When a rug helps your horse and when it harms

As soon as the first night below freezing is forecast, rugs appear over the stable doors in many yards. The question behind it is a fair one: is my horse cold? For most healthy horses the honest answer is: less than we think. A horse is built for the cold. But there are horses that genuinely suffer without a rug, and there are rugs that do more harm than good. The difference can be learned.

Horses are built for the cold

We judge cold from inside our own skin. For us, zero degrees is unpleasant; for a horse with a winter coat it is often comfortable. Horses come from open landscapes with cold winters, and their bodies are made for it. In winter, many horses struggle more with too much warmth than with too little.

A horse has two sources of heat that we do not have. The first is the winter coat, which grows in autumn, triggered by the shortening days. The second is digestion. When hay and straw are broken down in the large intestine, heat is produced, and a lot of it. That is why experienced horse people say: the best heater for a horse is a full hay rack.

Which brings us to the most important sentence in this article: a horse that has enough forage in winter feels the cold far less often than one that eats too little. So before you think about a rug, look at the hay rack first.

How the winter coat keeps warm

The winter coat is denser and longer than the summer coat, but it only shows what it can really do in the cold. Tiny muscles at the hair roots make the hairs stand up. Between them a cushion of air forms, and air is one of the best insulators there is. If you run your hand over an unrugged horse on a frosty day, the surface often feels cold while underneath it is warm. Sometimes there is even frost lying on its back without the horse being cold. That is not a warning sign but proof that the insulation is working.

A rug flattens this coat. It replaces the insulation instead of adding to it. And because the body notices that it is warm under the rug, it grows a less dense coat. Hence the rule: if you rug early in autumn, you usually have to rug all winter. A horse that has come through autumn without a rug has a winter coat that will see it through the winter.

Wet and wind are the real problem

A healthy horse copes well with dry cold. It gets difficult when several things come together: rain that soaks the coat right down to the skin, and wind that chills the wet surface. A wet coat barely insulates any more, because the cushion of air collapses. A horse standing in persistent rain at five degrees with no shelter can be colder than one at minus ten in dry air.

So the first question is not how cold it is, but how the horse is kept. Does it have a field shelter it can retreat into when it rains and blows? Does it have a hedge, a wall, a windbreak? A horse with good shelter needs a rug far less often than one standing in an open field with no protection.

If there is no shelter and the weather stays wet and windy for days, a waterproof turnout rug with no fill or only a light fill can make sense. It keeps the coat dry and still lets it do its job.

When a rug really makes sense

Some horses do need a rug, and for them it is not a question of comfort but of health:

• Clipped horses. If you remove the winter coat because the horse is worked hard in winter and would otherwise sweat heavily, you take away its insulation. A clipped horse has to be rugged.
• Old horses. Many older horses grow less coat, chew less well and can no longer hold their body temperature as easily.
• Thin or sick horses. A horse with few reserves uses up on keeping warm what it actually needs for other things.
• Horses with a fine coat, such as many Thoroughbreds and Arabs, which naturally grow less winter coat.
• Horses with no protection from rain and wind, for as long as the weather stays wet and cold.
• After riding, when the horse is sweaty: a cooler until it is dry, then off again.

For everyone else: watch rather than rug just in case. A healthy horse living out with shelter and hay ad lib does not need a rug in most winters.

How to tell if your horse is cold

The ears are a poor guide, even though that is exactly where many people feel. Ears and legs are often cool in cold weather without the horse being cold. Your hand in the right place is more reliable:

• Reach under the coat or under the rug at the chest, shoulder and flank. If it feels warm and dry there, everything is fine.
• Shivering is a clear sign of being cold. A horse that is shivering needs shelter, hay and, if necessary, a rug.
• A hunched posture with the head low, the tail clamped and its back to the wind, over a longer period, shows that it is uncomfortable.
• Weight loss over the winter can mean that the horse needs too much energy to keep warm or is getting too little forage.

If the horse feels damp or hot under the rug, it is too warm. That happens more often than you might think, and it is not harmless.

Too warm is a problem too

A horse that sweats under a rug that is too heavy is then left standing in a damp coat. If it turns cooler, at night for instance, it gets chilled under the wet rug. This happens quickly in changeable weather with mild days and cold nights, when the rug goes on in the morning and is not adjusted.

Too much warmth can also put a strain on the airways. A horse that keeps switching between sweating and chilling is more susceptible. If your horse coughs in winter, read my article on coughing in horses. Often the cause lies not only in the lungs but in the stable air, the dust and exactly these changes in temperature.

So the rule of thumb is: better one rug too light than too heavy, and adjust it when the temperature swings a lot. Several rugs of different weights are more practical than one very warm one.

If you rug, do it properly

If your horse needs a rug, the way you look after it decides whether it helps or harms:

• Check the fit. A rug that rubs at the shoulder or withers causes bald patches and sore skin. Look underneath regularly.
• Take it off and check every day. Under a rug that stays on for weeks, injuries, skin problems and weight loss go unnoticed.
• Only on a dry coat. A rug on a wet horse traps the wet.
• Change wet rugs. A soaked rug without a waterproof outer layer is worse than none.
• Adjust surcingles and leg straps so the horse cannot get caught up when it rolls.

The whole picture matters more than the rug

The rug question is a small question within a big one: how is my horse doing in winter? Forage, water that does not freeze in winter, a dry place to lie down, movement and company contribute more to health than any rug. With these basics in place, you can use the rug as a tool you only reach for when it really helps.

That is why, in my work with horses, I never look only at the coat in winter. I look at how a horse eats, how it stands, how it moves and how it gets on with its herd. A horse that feels good shows it. So does a horse that is cold.