November/December 2018 |

It's the question we Canadian horse owners ask ourselves every fall: Do I need to start blanketing my horse yet (or ever)? The first step in figuring out the answer is to understand how horses control their internal temperature.

In their natural state, horses control their internal heat by a rather complicated, but very efficient physiological mechanism called thermoregulation. In fact, they are particularly well adapted to handle cold weather.

To begin with, the horse's coat serves as insulation. As days become shorter and cooler the winter coat comes in, longer and thicker than the summer coat. In addition to the heavier coat, the horse can increase insulation through piloerection, a mechanism through which the hairs can be raised, turned, or lowered by the hair erection muscles. Piloerection can increase coat depth between 10 to 30 per cent in adult horses. Finally, the horse's hairs are coated with an oily substance called sebum that helps to repel rain and snow, keeping his skin dry. Through its relative thickness, the skin itself works as a further layer of insulation. Arteries in the skin can be constricted or dilated, regulating blood flow to the skin. Constriction of these tiny arteries prevents internal heat loss by reducing the amount of warm blood brought to the cool surface of the skin. The amount of body fat is also an essential factor. In general, a horse with a good layer of fat will keep his body temperature better than a thin horse, due to the fatty tissue's low thermal conductivity and poor blood supply.

Aside from the actual weather (taking into account air temperature, wind chill and precipitation), there are a number of factors to consider when deciding whether or not your horse needs to be blanketed. These include:


Northern-type horses such as Haflingers, Fjords, Canadians, Shetland ponies, Welsh ponies and the more rustic lines of Quarter Horses, Paints and Appaloosas, tend to have rather round, heavy bodies and short limbs. Along with a thick winter coat, a long mane, and furry ears, they are able to retain their body heat better than most long-legged, hot-blooded (Thoroughbred and Arab-type) horses.

Age and general health: 

Foals and senior horses have more trouble keeping warm than animals in their prime. Senior horses tend to have trouble keeping weight on and may burn essential body fat in an effort to keep warm. The same is true for chronically ill or recovering horses.


Eating helps to increase heat production in the horse's body. In cold weather, horses should have unrestricted access to hay. Depending on the other factors, you may need to increase feed intake to help your horse maintain his weight and body fat and therefore, his body temperature.

Living conditions: 

Horses living outdoors or that are turned out for several hours every day must have shelter, which can reduce heat loss up to 20 per cent by protecting them from wind, rain and snow. If they are in good health and have a thick winter coat, horses may not need to be blanketed unless temperatures fall to extreme lows or they become wet. Horses kept indoors that are partially or fully clipped, horses that have recently moved from a warmer climate, or horses with health problems will probably need blankets, even if they are only turned out for short periods of time.

If you decide your horse would indeed benefit from blanketing, the next question is: Which blanket to choose?

Major equine apparel manufacturing companies offer a wide variety of turn out rugs, blankets and sheets for every need and every budget. Gone are the days of the dreaded New Zealand rug. Modern turn out rugs have a reasonably light-weight outer shell made of polyester, nylon or a combination of these, with an inner lining of nylon, polycotton or polar fleece. In addition, most models have hind leg straps to help keep them in place when your horse rolls or runs. Stable blankets may be made from nylon, polyester, cotton, a cotton blend, polar fleece or some combination of these, and may or may not have hind leg straps.

Aside from the obvious ones of proper size and fit (see sidebar on page 57), there are three important factors to consider when choosing a blanket.

The first is denier, which is the measure of fibre or thread density. The higher the denier of the blanket's outer shell, the stronger and more durable it will be. This is especially important if you have one of those horses that enjoys ripping his blankets to shreds.


210 denier: very light strength 

420 denier: light strength 

600 denier: medium strength 

1200 denier: heavy strength 

1600 denier: extra heavy strength 

2100 denier: super heavy strength

The second factor to look at is fill, which indicates how warm the blanket will be. The higher the weight number (in grams), the warmer the blanket will be.


No fill: no real warmth (may offer some protection from wind and rain)

50-150 grams: light warmth

250-250 grams: medium warmth

300 grams: heavy warmth

400 grams: extra heavy warmth

Most horses can handle whatever winter throws at them with some extra hay to keep them warm, and shelter to provide an escape from the elements.

The third thing to look at is whether or not you need the blanket or rug to be water-resistant. Turn out rugs and sheets are by necessity windproof and water-resistant, while stable blankets generally are not.

While a partially or fully clipped horse or one with a sparse winter coat may need to wear a blanket even when he's in the stable, it's never a good idea to overdo things. Constant blanketing or a too-heavy blanket can flatten the horse's coat, preventing piloerection and thereby reducing his natural insulation.

Blankets should be breathable and fit well to prevent shifting or rubbing. They should be removed regularly and horses checked for body condition, injuries, and skin problems such as rain rot or ringworm, which can be caused by humidity. Finally, make sure your horse isn't over-dressed. If you find him sweating beneath his blanket or if temperatures rise, change or remove the blanket accordingly. Overheating can actually pose more of a risk to your horse's health than the chilly winter weather. 

Measure Twice, Buy Once

You want to be sure to get it right. If a blanket is too small, it can rub or restrict movement. If a blanket is too large, your horse can step on it or become entangled in it. Blankets either run in 2" increments

(American sizing: 66", 68", 70", etc) or 3" increments (European sizing: 66", 69", 72", etc). If your horse falls between sizes, it is best to go up to the next larger size. You might also want to think about whether you are going to be layering this blanket over other blankets (if so, add an inch or two).


Temperature C

Clipped and stabled horse

Undipped and stabled horse

Undipped horse outdoors 24/7


Nothing or very light sheet




Light weight turn out rug

Nothing or breathable sheet

Nothing or breathable rain sheet (bad weather)

Medium weight turn out rug

Nothing or breathable sheet

Nothing or breathable rain sheet (bad weather)


Medium weight turn out rug

Nothing or light weight turn out rug

Nothing or light weight turn out rug


Heavy weight turn out rug

Nothing or medium weight turn out rug

Nothing or medium weight turn out rug


Heavy weight turn

out rug (hood optional)

Nothing or heavy weight turn out rug

Heavy weight turn out rug


Heavy weight turn

out rug (hood optional)

Nothing or heavy weight turn out rug

Heavy weight turn out rug


Heavy weight turn

out rug (hood & extra liner)

Heavy weight turn out rug

Heavy weight turn out rug

This chart is a helpful guide to the blanket size your horse may need according to their height. We always recommend measuring your horse as well. To measure your horse, start at the centre of the chest (A). Then go around the widest point of the horse's shoulder and follow parallel to the ground along the side of your horse to the point of their hind end where it meets the tail (B). On average, your chest to tail measurement will be the blanket size. But, this is only a guide. The length of your horse's back and the width of body will impact the size your horse needs.


Horse Height

Blanket Size (in)

Blanket Size (cm)

11.2 h


137 cm

11.2 -12.2 h


145 cm

12.2-13.2 h


152 cm

13.2 -14.0 h


160 cm

14.0 -14.2 h


168 cm

14.2 -15.2 h

69" - 72"

183 cm -190 cm

16.0 -16.2 h

75" - 78"

190 cm -198 cm

16.2 h

78" - 81"

198 cm - 206 cm

17.0 h

81" - 84"

206 cm - 213 cm

17.1 h


213 cm

17.2 h


220 cm  I   November/December 2018