By Maddy Butcher
In a thoroughly researched paper, Natalija Aleksandrova makes a strong, supported argument for not blanketing horses. Ever.
Aleksandrova, a horsewoman, hoof trimmer, and equine researcher, posted her essay, which cited 20 scientific references, on the pages of Academia Liberti, a school of holistic equine study based in Germany.
She appeals to horse owners to let horses take care of themselves. By blanketing and using other ill-advised horse management techniques, owners inadvertently rob horses of their natural ability to regulate their body temperatures.
Read about donkeys and blanketing here.
Read Dr. King’s article on Fewer Gifts, Better Care.
The researcher, who lives in Latvia, writes that horses have efficient, multi-faceted thermoregulatory mechanisms. They are perfectly adapted to staying warm all winter, given their anatomy, physiology, and individual and herd behavior.
Domestic horses only need conditions that the species should rightly have ‘by dictate of Nature,’ she writes.
- Freedom of movement 24 hours a day
- Free access to appropriate food (fibrous hay) 24 hours a day
- Herd life
- Proper hoof care
- Shelter that they can enter and leave freely
But what about these thermoregulatory mechanisms? Simply put: they’re how horses maintain their body temperature. These innate abilities can be broken down categorically:
Anatomy and Physiology:
The skin and coat are excellent insulators. In fact, due to horses’ anatomy and physiology, it’s easier for them to stay warm in cold weather than to stay cool in hot weather or after an intense workout.
Long before the first snow flies, horses naturally grow a winter coat. Coats vary by species and environment, but generally horses in colder climates have evolved to grow thicker coats.
In addition, horses increase the insulating abilities of their coats by as much as 30 percent through piloerection: the raising or lowering of the coat via hair-erector muscles.
Blanketing inhibits piloerection.
Horse hair naturally has an oily coating that helps shed rain and snow. Blanketing and over-grooming interfere with this innate, insulating trait. Read more about grooming practices.
“Needless to say, the popular practice of clipping the hair of a horse’s coat eliminates, completely, the thermoregulatory factor of the coat,” writes Aleksandrova.
Horses’ arteries constrict or dilate depending on thermoregulatory requirements. Constriction reduces heat loss by reducing the amount of warm blood brought to the cooler body surface (in winter, for instance). Dilation allows for a larger amount of hot blood from over-heated interiors to reach the body surface and to be cooled (during or after exercise and in hot environments).
Horses don’t hibernate, of course, but they may still add as much as 20 percent body weight in fat as cold weather approaches. 
That extra layer is important; fat is three times more insulating than other tissues, according to Aleksandrova.
Behavior
Horses may burn off some of that fat to stay warm, but they still need to eat more during winter. The shift is called climatic energy demand and it increases by about 1 percent for every degree decrease (Celsius). Metabolically, it’s essential that horses have ready access to fibrous fuel around the clock. The wood that heats their house is hay.
Wild horses conserve energy by moving less in the winter, so do domestic horses.
Horses may stand next to each other or use each other as wind blocks, thus “reducing the body surface area exposed to the environment and gaining heat from a pair or group source,” she writes.
Though not quantified by research, Aleksandrova observes that blanketing creates a 
No-Win scenario because the horse cannot heat specific regions of its body:
“The whole body cools or the whole body heats up. Sweating under a blanket is more of a problem metabolically to the horse than people realize.”
Blanketing forces the entire spectrum of horses’ mechanisms to languish. She writes:
“They don’t need to exercise hair erector muscles, nor to dilate or constrict arteries, nor to activate sweat glands, nor to prepare or deplete healthy fat reserves. All muscles atrophy without exercising for a period of time.
Horses under blankets effectively lose their ability to stay warm on their own.”
In conclusion, Aleksandrova speculates that other management techniques -“stabling, separating from equine companions, forced exercising, lack of continuous fiber (hay) uptake” – can compound their stress and inability to cope with cold.
I can find no article regarding blanketing on the Academia Liberti site. Can you give a direct link to the actual article?
Thanks for the heads up, Cheryl. Academia Liberti changed their pages on us! Here is a lengthy synopsis of her research.
Thanks for the good sense and supporting science. My horses are in pasture and free of blanketing. But as a new horse owner I had to withstand the pressure of folks who felt I should be blanketing. Luckily I had the advice of others who helped me understand it would create a real problem if I started. This article explains it well.
My horse is older and actually shivers in very cold weather. Sometimes I would find him shivering so much, I thought he was next to becoming hypothermic. He has access to shelter, has a good amount of fat, but never develops the thick coat of hair that does his pony friend who does not seem to be affected so much by the cold. My land is in a valley which tunnels the arctic blasts so that my pastures can become very windy. When my horse looks to be uncomfortable , I blanket him. When it’s 20 below zero with a wind chill of who knows what, not to blanket him would be cruel. I think you have to make judgements at times as to what is best for the individual horse. He loves his blanket!
Yes, I have an elder Arabian mare who does not grow enough of a coat to keep her from shivering either. She wears a Rambo medium rug and does great. Does not sweat under the blanket even after running around. In our wet PNW region, people deal with rain rot if they choose to go without the rain sheets. It can pour for a month straight at times.
Thoughts on vast differences in temp? A few weeks ago it went from 72 to 27 Fahrenheit where I live in the span of no longer than 6 hours. Stayed below 32 for a few days the back in the 60’s.
I agree with Fran. I too have to be very careful of windchill here on my hill. Add some moisture to it and I’ve seen my furry Shetland shiver. What Aleksandrova says is true. But like most opinions must be tempered with good judgement and common sense.
Our Donkeys and Horses are rarely if ever blanketed. As fall turn to winter, their coats will thicken nicely, and the Minnie Donkey will turn into a FIR BALL on STILLS. The colder it gets, the fluffier they get. If you are blanking your horse in the fall, you are inter fearing with the animals natural machoism to protective it’s self from the cold, you have now made the horse dependent on the blanket. If the Maine weather is that bad for the day, they stay in a nice warm barn. We do have blankets, including home made ones fore the Donkeys if a situation should arises.
I like the information you all share on the issues of blanketing. It makes sense for horses that are in decent health, have turnout/pasture, can eat when they chose (need to) and can find at least a wind break, if not shelter from wet. To me, where I would deviate will be in cases where the horse is not in good health, or has trouble maintaining weight. I see instances of horses only fed twice per day (and finishing it all having to eat standing out in rain). Not such a big deal until the temperatures go below freezing, and the wind and snow kick in. Then the soaked horse stands and shivers all night. If this goes on too long they become miserably stiff, and have a hard time keeping weight on. Unfortunately there are a lot of horses that are kept in situations that are pretty hard on their natural abilitiy to self-regulate. It would be wonderful if this would change. : )
Our equine vet has always told us: you don’t blanket a horse to keep them warm in winter, you feed them & provide appropriate shelter. They take care of the rest, with their excellent thermoregulation. This has always worked just fine for our horses. I appreciate seeing all the validation in this article. Thank you!
My horse doesn’t grow a winter coat and likes having a blanket. I know this because when he wants the blanket on I hold it up and he’ll stick his head through the neck opening and stands still to let me put it on. When he doesn’t want the blanket on he walks away. My horse also has shelter and access to food 24/7. Most people in my neighborhood only feed their horses twice per day and that’s not sufficient to help them take care of themselves.
I agree. Horses have evolved over 45 million years and only recently (6000 yrs) Humans began domesticating them. I would suspect that if blanketing continues then it may lead to a dependency within the species. This would take a couple thousand years give or take a few but why waste a good blanket now right? Humans….
This leads to the question of clipping in the fall and winter. If exercising your horse and they get really sweaty what is the danger that? Or do you clip them and then have to blanket them.
Here in the Pacific Northwest rainy season horses do get wet through.
I have 13 head of horses and mules and only blanket 2. One is pushing 30, has no teeth and has a thin build to start with. The other is 20 and has never really grown a heavy winter coat like the others. I have found that if I don’t blanket them, they lose weight. It depends on the horse and the circumstances. Until I got these two, I never blanketed anything.