The days are getting shorter, the thermostat is dropping, and we’re all finding ourselves reaching for our jackets and jumpers before stepping outside to see our horses.
Even though we’re starting to feel the chill, it doesn’t mean we should immediately layer on the heavy Winter rugs without understanding how our horses manage cold weather.
The reality is that your horse feels the cold weather very differently to how you do. Their bodies are radically different to us in terms of size and composition. After all, we don’t have a natural thick layer of hair covering us to keep us warm!
In this horse rugging guide, we take a look at the science of thermoregulation in horses and how they adapt to some of the world’s extreme temperatures of heat and cold to help you navigate the oftentimes overly complex world of rugging horses.
The Highly Adaptable Horse
Evolved over the past 45 to 55 million years, the modern day equus ferus caballus (the horse) is a remarkable warm-blooded mammal that can be found living in temperatures ranging from -40°C to 60°C.
Through thermoregulation, your horse aims to maintain a central (core) temperature of 38°C, or as close as possible, despite how hot or cold the weather may be.
In the harshest of environments, the extremities of your horse’s body, such as their hooves, may fall to 5-10°C or reach up to 60°C when standing on hot ground!
Your horse’s thermoneutral zone ranges from 0°C (the lower critical temperature) to 25°C (the upper critical temperature). Most horses will feel cold when the temperature falls below 0°C or hot when it rises above 25°C.
While there is some variation to this depending on the horse’s age, breed, feeding regime and body condition, when a horse is within the thermoneutral zone, they can easily control their body temperature by opening and closing blood vessels in their skin.
However, at temperatures below freezing (0°C), your horse needs some additional help to stay warm. This can be achieved in several ways:
- Eating quality forage: continuous access to quality forage creates internal heat when the fibre is fermented by the horse in their hindgut
- Increasing metabolic rate: those extra pounds gained through Summer enable the horse to use more energy to keep warm
- Using natural insulation: a thick insulating Winter coat allows the horse to trap heat, forming a warm layer of external body heat
- Seeking shelter: natural and man-made shelter provides the horse with respite from persistent wind, rain, or snow, as well as huddling closely with their herd
- Bodily responses: blood flow to the outer limbs may drop as its diverted to the core and in very low temperatures, the horse may also shiver
To Rug or Not to Rug
That is the question! Before we answer it, we should ask ourselves why do we rug horses and when is it necessary?
We typically rug our horses for three reasons: to keep them warm, to keep them dry, and to keep them clean.
The main thing to remember when rugging is don’t rug your horse based on how cold you feel! Horses in good health, with access to continuous forage and free-choice shelter may not need to be rugged at all unless temperatures overnight dip below 5-10°C.
Rugging is important for old, young, and ill horses, those in poor body condition and those with a naturally short Winter coat or a clipped coat. The best rule of thumb for any rugged horse is to start with lighter rugs and change to heavier rugs over time.
Over-rugging is risky business if not managed correctly:
- Too much heat produced under the rug will cause your horse to sweat, causing rubbing which can lead to wounds and infections.
- If left on too long, a thick rug can prevent sunlight from penetrating your horse’s coat, limiting vitamin D absorption that supports bone health.
- A thick rug prevents heat loss which may lead to your horse gaining weight over Winter doubling the risk of laminitis for certain breeds.
To determine if your choice of rug is right for your horse and to avoid over-rugging, there are some simple checks you can do:
- Feel your horse’s legs, face, and ears to see how warm they are without a rug.
- When rugged, place your hand on the wither area. If the area is cold, a thicker rug may be needed. If its damp, the rug should be removed as your horse is sweating.
- After a month of rugging, you may find your horse becomes acclimatised to the cold weather. In that case, a thinner rug, or no rug at all, may be needed.
- Always allow your horse to turnout without a rug for a minimum of one hour per day, preferably when the sun is warmest, to provide a daily dose of vitamin D.
Choosing the Right Rug
Selecting the correct rug for your horse, including fit, material and thickness, is not just for their comfort, but is a matter of health and welfare. The wrong rug can interfere with your horse’s natural insulation or over-heat them, leading to stress and possible weight gain.
Below are some tips recommended by the British Horse Society which you can use as a guide for rugging horses:
- Denier: this rating relates to the outer fabric of the rug. The higher the denier, the hardier the rug, so opt for a high denier if your horse has a history of ripping rugs.
- Fill: this describes the rug’s weight, which will fall into one of three categories – light weight (0g, 5g, 100g), medium weight (150g, 200g, 250g) and heavy weight (300g+)
- Consider the following when choosing a rug for your horse:
- Time of year
- Level of work
- Feeding regime
- Access to shelter
- Provision of forage
- Body condition score
- Local weather conditions
- Coat quality – is it thin or clipped?
Just like your horse’s saddle, their rug may need to be refitted or changed as their body weight and condition fluctuates. All rugs should be removed daily to check for any signs of over-heating or rubbing. The right rug will keep your horse warm, comfortable and healthy.
Incorrect & over rugging in mild or seasonal change weather such as Autumn, can lead to sweating and your horse getting a ‘chill’ which can result in respiratory symptoms. So don’t underestimate the importance of rugging appropriately for the season and if in doubt, go lighter – they will burn calories/energy to keep themselves warm, but its more difficult for them to cool themselves if they are too hot.
Disclaimer: This article is not intended to replace professional veterinary advice. Always consult your veterinarian if your horse as any health-related issue or is exhibiting symptoms.