If you've ever shopped for an electric blanket for your bed, you may have been surprised to find that there were two sets of controls. That's because there seems to be an unwritten law of nature that no two people can agree on a perfect temperature. That same unwritten law says that no two horse people will agree about blanketing horses—when to blanket, how heavy a blanket to use, and the myriad variations of those questions.
Rather than tell you any hard and fast rules (since there are none), we'll give you some guidelines to help you figure out what's best for your horse and his situation. You might be surprised to find that, in some cases, not blanketing is actually the best decision.
Equine Thermal Energy
We'll begin by looking at the horse himself. Horses stay warm much better than people do, and they are quite comfortable even when you and I might be reaching for a jacket. In short, you can't determine a horse's need for a blanket by how chilly you feel.
The primary way a horse gets or stays warm is by digesting hay. Digestion is really a fermentation process, and one of the by-products is heat. When your horse is facing a cold night, the first consideration is to provide him with plenty of hay to keep that furnace burning. And in order for that digestion process to work well, he needs water. Ideally it won't be ice cold.
The horse's bulk is a great help in keeping warmth in. Think of how thick a horse's body is, relative to the slender frame of a human. Just as a large block of ice takes longer to thaw than a smaller chunk, a large, warm body stays warmer longer than a thin one.
On top of that, a horse's winter coat has the ability to fluff up, the hair literally standing on end, thereby creating a warm layer of air around the horse. Long "guard" hairs create an additional layer and fend off light rain or snow.
Even though it's cold out, an average horse in good condition, eating plenty of roughage, and wearing his own hair coat is probably going to stay warm—as long as he can stay dry and isn't in direct wind.
When to Blanket
The farther you get from the ideal, the more appropriate it is to consider a blanket. Not every horse has a wooly coat. Some breeds of horses have thinner coats, and others have thin coats from blanketing, being under lights, living in a warm climate or barn, or having been clipped. Even within a barn, you may find one horse who doesn't need a blanket, another who just needs a sheet at night, and another who seems to require a winter parka.
But a fuzzy coat isn't the only determining factor. Consider whether the horse is underweight, isn't eating enough roughage, isn't able to get out of the wind or wet, or has some health concern that compromises his ability to stay warm. Remember, though, when you put a blanket on your horse, you squash that natural insulating layer of air in his coat. In borderline situations, he may actually be more comfortable wearing his natural blanket than your store-bought one.
It's usually necessary to blanket a body-clipped horse. You can layer blankets, the way you might wear a light sweater under your coat. And for any horse out in wet weather, keeping him dry is key to keeping him warm.
If the horse isn't body clipped, you have the dual challenge of cooling the horse down after a workout without allowing him to get chilled. You'll need to put towels or a wool cooler under a light sheet and remove the towel or cooler as it gets damp.
With any horse, you should periodically reach under the blanket to be sure the horse isn't hot or sweaty, especially a horse who has been worked, because he can appear cool but then get sweaty again once he is back in the stall.
Though horses adapt to changes in climate, they don't adapt well to rapid changes. So the horse who was fine when left unblanketed last week might benefit from light blanketing tonight as the leading edge of a cold front comes through. Remember that the big worry during weather changes is that the horse may colic, often due to decreased drinking. So while blanketing is important, having not-too-cold water is critical.
Some owners think they're doing their horses a favor by closing up a barn to keep their horses warm. But they're also closing in ammonia fumes and allowing moisture to build up. So instead of heating the barn, it's better to blanket the horses and allow for plenty of ventilation.
It takes calories to stay warm, and some horses need all the calories they can eat. That's especially true of older horses who have difficulty chewing or holding weight, and of horses who have been through a health or shipping stress. In those cases, blanketing helps conserve energy and boosts their ability to stay warm.
If blanketing is the best option for your horse, try to avoid having him wear the blanket 24/7. Even a little unblanketed turnout time in the sunlight on a winter day will do most horses good—whether to have a good roll or just to give their skin a breather from the blanket.
Once you've decided that your horse might benefit from blanketing, you still have plenty of smaller decisions to make. Does he need a light blanket or sheet for daytime and a heavier blanket for night? Will he be turned out, necessitating a waterproof blanket, or does he just need a stable blanket for time indoors? Will he be turned out with other horses who will run and play? If so, he needs a blanket that will survive that.
Or will you turn him out blanketless, but then groom him before re-blanketing? If he rolls in the mud with his blanket, what will he wear while you're washing the muddy one?
And aside from the cost of buying a blanket or two, there's the time commitment that goes with blanketing and unblanketing, day after day. Who is going to do that work? If your horse is cold, blanketing may be your best option. But if you have choices, such as whether to body clip him or not, other time and nuisance factors come into play.
There's the matter of keeping the blanket clean. Depending on the blanket materials, that may mean brushing the underside of it daily—or at least checking it—to remove any hay, hair, or stickers that could potentially rub against your horse's coat. It may mean washing the blanket, which also means drying it thoroughly before putting it back on your horse. This likely means you're going to need a second blanket. Don't forget that it's inevitable that you'll have to do some repairs—even if it's only to reattach a buckle.
Even with a blanket, which will help keep your horse clean, you should groom your horse every day. He'll get itchy wearing a blanket, just as you would if you wore the same sweater day in and day out.
If your horse is turned out with his blanket, you have to make sure that the fabric doesn't absorb and hold water when it gets soaked. A wet blanket will get a horse cold very quickly. Read the labels carefully. "Water-resistant" may be fine in a light mist, but you need "waterproof" if your horse is to stay out in the weather. And that means you'll have to re-weatherproof it after cleaning.
Of course, you'll have to be sure that the blanket fits well and doesn't rub your horse's coat. Even if it seems to fit, keep an eye out for the telltale hairs that seem as though they've been shortened, as if newly clipped or roughed up. This often happens over the hips, on the shoulders, or around the neck opening or withers after the horse has been wearing the blanket for a while.
When the hair gets rubbed, the skin will become tender also. For some horses, even a good-fitting blanket will eventually rub, so he may need an undergarment that will allow the blanket to slip along his shoulders more easily.
And even when everything works perfectly, you can still come home to find your horse naked and your blanket investment shredded by a naughty pasture mate.
As in most things, getting by as nature intended is generally your best option. But when blanketing is the right choice, you get to enjoy the warm feeling of knowing you've done your best for your buddy.