How horses can withstand cold
- By Jenny Austin
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- 13 Oct, 2023
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How do horses stand the cold and not need rugging?
Horses have the ability to withstand the cold far better than us. There are several things about their bodies that come together to provide the horse with the ability to live in cold climates. We clever humans, with our high-tech fabrics still haven’t created anything to match the cold-beating mechanisms of the Horse.
Here’s how they do it.
Evolution
Humans originated in central Africa, our energy-neutral (no extra energy expended to maintain body temperature) range is about 10 to 29 degrees Celsius. Horses, on the other hand, evolved further north in higher elevations where it is extremely cold. Their energy-neutral range is about -9 to 15 degrees. That’s why our horses delight in weather that seems freezing to us. Our bodies are designed to dissipate heat, but horses are fabricated to produce and maintain it.
Digestion
The horse’s enormous digestive tract generates a large amount of heat while processing fibre.
Body Design
The blocky body, like moose, elk and other cold-weather herbivores, retains heat really well. The limbs of the horse have less muscle than humans, therefore need less blood and consequently lose less heat. The thick, roundish muzzle has a rich blood supply to withstand the cold. The very long journey that air takes from the nostrils to the lungs warms the cold air on the way.
When they need to warm up
Of course horses aren’t completely cold resistant. Sometimes certain factors can rob them of body heat and they need to warm up. The obvious first solutions are turning rumps to the wind, getting closer to herd buddies, seeking shelter or moving more. If these behavioural responses fail, the body has some mechanisms to cope.
Shivering
This extremely fast tensing and relaxing of the heavy muscle groups quickly heats up the body. Horses are superb at shivering; it’s more comfortable for them to shiver than it is for humans.
Heat Exchange
In extreme cold, the blood takes a detour to deep under the skin, close to the arteries. Blood returning to the heart and lungs is warmed by the outgoing arteries preventing cold blood from penetrating the core.
Piloerection
Each hair follicle has a muscle attached to the base of it, which lifts the hairs up to create an insulating layer of air between the skin and hair. Rugs prevent this from happening by flattening the hair follicles and eventually the muscles atrophy.
Shutting off circulation to the extremities
Shunts open up in the feet so that blood flows from the smallest arteries directly into larger veins, called venules, without passing through the capillaries. After the feet have warmed sufficiently, the shunts close again to restore nutritive capillary flow. Shunts are also used in the tail and ears.
Metabolism
As cold continues to stress the body, the thermo-regulatory centres turn their attention to generating more internal heat, sending out messages to the adrenal glands to boost core metabolism.
Acclimatisation
The horse prepares for the cold long before winter, right after the longest day of the year. Receptors in the eyes (and other parts of the body) relay information to the brain. This triggers the release of hormones to prepare the coat for winter. During the autumn, ambient temperature determines how long and thick the horse's winter coat grows. If he is exposed only to warm air or is rugged or stabled, the winter coat will grow in only slightly heavier than the summer coat. On the other hand, if it’s exposed to extreme cold during this time, the coat will be correspondingly thick and long. Your horse's winter coat consists of different kinds of hairs that together create a loft within a layer of body-warmed air next to the skin. The downward tilt of the hairs deflects falling rain before they reach the skin and directs them to the hair tips, from which they fall to the ground. As the temperature drops, the horse's appetite and calorie intake increase boosting heat-generating digestion and metabolism. On the cellular level, heat-generating metabolism is also increased for the winter. As cold sets in for the long term, the hypothalamus signals the pituitary to release thyrotropin or thyroid-stimulating hormone (TSH). Reaching the thyroid gland in the neck, TSH triggers the release of thyroid hormones that slowly boost metabolism for the winter months. The impact of all these changes is a marvel of thermo-regulation. Efficiently generating more heat while increasing his layers of insulation, the acclimatized horse has greatly improved his ability to tolerate cold. It will take a really severe cold spell to force him to resort to fuel burning and other emergency warming responses like shivering.
Are you aware of the Five Freedoms in the Animal Welfare Act? This Blog explains how we interpret these and put them into practice in our daily dealings with our own and clients’ horses. They are:
- Freedom from hunger and thirst: by providing enough fresh water and the right type and amount of food to keep them fit.
- Freedom from discomfort: by making sure that animals have the right type of environment, including shelter and somewhere comfortable to rest.
- Freedom from pain, injury and disease: by preventing them from getting ill or injured and by making sure animals are diagnosed and treated rapidly if they do. Animals should have access to veterinary care when needed.
- Freedom from fear and distress: by making sure their conditions and treatment avoid mental suffering.
- Freedom to behave normally: by making sure animals have enough space, proper facilities and the company of other animals of their own kind.
Number 1 Freedom of the Animal Welfare Act is “Freedom from Hunger and Thirst : by providing enough fresh water and the right type and amount of food to keep them fit”. Now this can sound very straightforward but it’s easy to get it wrong and is a massive topic. Here at TTT :
· We ensure that horses in our care have 24/7 low ESC+starch grass hay, plus grazing. If they are losing weight we might add in some higher calorie hay such as lucerne or a cereal hay.
· The most important part is that it’s 24/7 low starch, high fibre “trickle feeding” as suits horses digestive systems.
· We have in our training contract that if owners wish their horse to have a bucket feed, that they must supply that as an extra, and we are happy to give them whatever is instructed.
· We will contact the owner and suggest a more energy dense bucket feed if the horse is losing weight on hay/grass.
· Our own horses have a small feed of rinsed and soaked beet pulp, lucerne chaff, salt, a custom mineral mix and some have other supplements as needed for joint and gut health.
· Our horses, if in work, will have soaked, cracked lupins added and we give whole oats after hard work.
· Of course, we always have fresh water available.
· We have heard recently of a trainer using feed/water restriction as a training tool – that is cruel and unnecessary and would never, ever happen here.
Number 2 Freedom of the Animal Welfare Act is “Freedom from Discomfort by making sure that animals have the right type of environment, including shelter and somewhere comfortable to rest.”
This one is fairly simple- here at TTT:
· Horses are paddocked with a suitable companion, not yarded or stabled, with room to browse and move around. There’s soft sand to sleep on, trees for shelter and a lovely outlook.
Number 3 Freedom of the Animal Welfare Act is “Freedom from pain, injury and disease: by preventing them from getting ill or injured and by making sure animals are diagnosed and treated rapidly if they do. Animals should have access to veterinary care when needed.”
This one is not as straightforward as it seems and is closely linked to Number 1 and 4. Here at TTT:
· Equipment is tailored for the comfort of each horse, not for the trainers’ comfort, to eliminate pain from ill-fitting equipment.
· We never hit or beat a horse with anything.
· We never tie up their legs or similar acts which cause pain and injury.
· We don’t work horses to exhaustion or expect paces that they are not physically ready for.
· The environment is free from hazards and as safe as we can make it to minimise risk of injuries.
· We ask owners to have their horses in good condition upon arrival, with their teeth and worming recently attended to and with full disclosure of previous injuries, illness and disease.
· We only provide companions which are suitable for settling new horses, not those which will harass or are aggressive.
· We feed as per Freedom Number 1 to keep the horses healthy
· Owners are notified immediately of any health concerns and our contract states that we will call a Veterinarian anyway if we deem it necessary but we can’t reach the owner first.
Number 4 Freedom of the Animal Welfare Act is “Freedom from fear and distress: by making sure their conditions and treatment avoid mental suffering”.
This one is also complicated and very much open to interpretation. Here at TTT:
· Our training method keeps the horses stress levels under their fear threshold. The physical signs of stress have been identified and well documented by the equestrian science community and because of our extensive experience we are able to immediately identify the symptoms of stress. Anything that escalates stress and adrenaline is counter-productive to good learning.
· We don’t implement some common and popular training methods that can cause fear and distress. For example, excessive use of the round pen; excessive circling/lunging; use of restraints e.g. hobbles, side reins and the like; excessive use of lateral movements, etc.
· We aim for calm at all times and achieve this by breaking down training outcomes into individual elements, then establishing one outcome at a time until it is thoroughly understood. Richard’s Passive Focus Exercise is one way to attain calm.
· We do not progress to faster gaits until we have established good responses to our aids in the slower paces and until the horse has developed good strength and balance. This ensures smooth transitions, communication and minimum stress at all paces.
Some points are copied from Freedom Number 3 as they overlap, i.e. physical and mental suffering can be caused by the same thing -
· Equipment is tailored for the comfort of each horse, not for the trainers’ comfort, to eliminate pain (and distress) from ill-fitting equipment.
· We never hit or beat a horse with anything (causes pain and distress)
· We never tie up their legs or similar acts which cause pain and injury (and distress)
· We don’t work horses to exhaustion or expect paces that they are not physically ready for.
· We only provide companions which are suitable for settling new horses, not those which will harass or are aggressive.
Number 5 Freedom of the Animal Welfare Act is “Freedom to behave normally: by making sure animals have enough space, proper facilities and the company of other animals of their own kind.”
This one overlaps and encompasses the first 4 Freedoms. So, as a summary, here at TTT:
· Horses have 24/7 spacious paddock living with grazing or ad-lib mixed species grass hay
· They have carefully matched companions
· They have trees and valleys for shelter
· They are very closely observed throughout the day (and we can hear them at night)
· We are extremely experienced and notice the tiniest issues before they escalate
· We are educated in nutrition, hoof care, conformation and riding disciplines
· Emotional, mental and physical health of the horses is our number 1 priority
Richard van Dijk & Jenny Austin
