EquiSearch's Ask the Vet: Horses in Cold Weather How do I know if my horse is cold? Should I blanket him in the winter? Dr. Joyce Harman answers these cold-weather questions and more in this edition of EquiSearch.com's Ask the Vet.
There are a few reasons to use blankets and a bunch not to. Horses who are clipped need to be blanketed, since we have taken their fur off. There are many wonderful, lightweight and well-fitting blankets on the market (blanket fit is for another day). Old horses who cannot keep warm need blankets, even if they never needed them when they were younger. In nature those old horses would have been eaten by a mountain lion, so they would not need a blanket. Horses who have been sick, are too thin, have been rescued or have any other health problems may need blankets. Some individuals of any age are cold-natured and really do need to be blanketed, as do horses who have no shelter. The rest of the unclipped population does not.
How many blankets do horses need? That depends on how much clipping has been done and the weather conditions. However, in most cases a single blanket will do the trick, with heavy blankets being used in the cold weather. You can stick your hand under the blanket and if it is toasty and warm, it is heavy enough for the weather. If it feels cool under the blanket, you may need a heavier one. Please do not get a great fitting outer blanket and add an old-fashioned design sheet underneath. The sheet does not add much warmth, and it usually rubs the shoulders and causes a lot of pain.
If you choose to blanket and start early in the season you will need to keep it up, since the horse will adapt to wearing it, and his temperature regulation will be accustomed to it. Most of the time we blanket because we humans are cold and think our horses must be, too. A vet friend of mine visiting early one December from Vermont remarked that the horses she saw in Virginia had many more layers of blankets on in December than her clients' horses had on in Vermont in January. Hmmm... they are all horses, right? So what is the difference? Vermont owners are accustomed to the cold, so they expect their horses to be adapted as they are. Virginia owners see much less cold weather, so they think their horses are cold when they are cold. The horses in Vermont were all warm and happy with single blankets.
If you do blanket, remember that a horse's fur fluffs out when it is cold. This adds air space like your down jacket has, and that air fills with warmth making the fur more efficient. Blankets crush down that air space, so you need a heavy enough blanket to provide true warmth. A thin sheet may protect a horse from rain, but it may not provide much warmth and may leave the horse colder than if he had no blanket.
How do you tell if your horse is warm enough? You have to get to know your horse and pay attention to small behaviors. Horses who are cold tend to huddle up in a sheltered place and may not be willing to go out into the pasture area even to eat hay to keep warm. They may really crave their stalls. They may shiver. However, shivering is also just a perfectly normal way to warm up, so a warm horse may shiver for a short while when he is cold and be happy. The cold horse will be seen shivering much more frequently or when all the other horses are not. Wet cold weather is harder on horses than dry cold, and a rainy 35-degree day will cause a lot more shivering than any other weather condition. Horses really appreciate some sort of shelter on those wet days, so they can dry off a bit and get warm. But it will not hurt a healthy horse to be outside and get wet and shiver a bit. Sheds are most used on rainy days, while a 10-degree day with snow may not find a single horse near the shed since they are happy in the cold.