You will rarely see horses suffering from frostbite. This is because horses are able to withstand cold temperatures much better than we do. In the fall season, horses begin to shed their summer hair, and it is then replaced by a thicker, longer coat. As the temperatures plunge, the horse stores more fat beneath the skin, and this provides much-needed insulation against the biting cold and reduces the loss of body heat. This is because the blood vessels that give off heat during summer are located deeper below the skin when winter arrives.
Unlike humans who suffer from frostbite when their fingers, noses, and toes are frozen by very cold temperatures, the muzzle of a horse has a rich supply of blood and can tolerate severe cold without getting frozen. In addition, the slender legs of a horse consist mainly of tendon and bone. This means they lose less heat and need less blood than muscles, making them less susceptible to frostbite. The hooves are also dense and thick which helps to protect the inner tissues of the feet. A horse’s blood circulation system is able to function without a lot of blood in the hooves. During very frigid temperatures, blood flows directly from the arteries to the veins without having to pass through the capillaries. This mechanism helps to prevent the horse’s feet from freezing.
The mane and tail of a horse also offer protection. The mane offers insulation and protection from water to the neck and head. Further, by instinctively turning its back to the wind, a horse protects its face and neck, which have thin skin and more blood vessels. The tail protects the delicate reproductive organs from extreme cold. Cid Hayden, a vet from Salmon, Idaho points out that moving around outdoors in severe weather also helps horses by keeping the blood circulating in the body. This makes them less vulnerable to getting chilled than if they were lying on the ground chewing the cud.
From time to time, however, abnormally cold temperatures can cause frostbite in horses. Among adult horses, this is manifested by loss of the ear tips which fall off within one week. Cold weather can be deadly to foals since they have little body fat. If not warmed up immediately, newly-born foals are susceptible to frostbite and hypothermia. However, horses usually give birth in summer or spring unless one wants to use artificial methods to make them breed them in winter. In that case, the mares need to be monitored round-the-clock.
Dangers of frostbite
Katharina Lohmann of the Western College of Veterinary Medicine, Saskatchewan notes that despite the extremely cold winters in the area frostbites among adult horses is quite rare. But it is experienced more in foals where some can be seen without part of their tails and ears. Sometimes their feet may even slough off. Lohmann adds that there are some horses without ear tips due to frostbites when they were babies.
A newborn foal that is not nursed immediately is at a high risk of getting cold stress. The first milk - also called colostrum - has twice the fat content of normal milk. This milk is essential for giving the foal energy and warmth for the first critical hours after birth. The feet of an adult are remarkably resistant to extreme cold. Chris Pollit, a scientist studying how to prevent laminitis (hoof inflammation) using ice water, found that a horse can endure standing on a bucket with ice-cold water for 48 hours continuously. Hayden has also seen a group of horses that stood in six inches of snow without shelter for two weeks at temperatures of 30 degrees Fahrenheit without suffering from frostbite.
According to Katrina Lohmann, a horse that is moving around is much less prone to frostbite than one that is sick and lies down for long periods. Even cattle that are suffering from arthritis and are unable to rise up can become hypothermic and freeze to death. In addition, a horse in poor health is less insulated from the cold since it has little fat stored under the skin and its blood circulation is compromised. Such sick animals are likely to get frostbite due to reduced blood supply in the body. An animal that is dehydrated due to diarrhea, for instance, is susceptible to freezing in the tail, feet, and ears. Lohmann stresses the importance of getting enough nutrition and having a shelter for horses during winter.
Older, skinny horses and young foals are usually at risk of getting frostbite since they have little body fat reserves. Other factors that enhance the risk of a horse suffering from frostbite are the levels of coldness, the duration of exposure to the cold conditions, and moisture. Wet skin that is suddenly exposed to cold - for instance, a newborn foal that is outdoors or a horse that is wet due to rain or sweat - is more likely to suffer from frostbite.
Diagnosing and treating frostbite
Frostbite results from ice crystals forming in the cell membranes which make the cells to rupture and die. If it affects the outermost layers of the skin, the layers may become discolored and peel away. Since the deeper layers are alive, the skin will eventually heal. When it has healed, the skin may lose its pigmentation. If frostbite affects the deeper layers of skin, it causes extensive damage resulting in the death of the tissues.
According to Cid Hayden, signs that a horse is suffering from frostbite include reduced sensation in the tissues and loss of flexibility in the skin. The skin then changes to black, but this is only visible where the skin is pink in color. Later, this skin hardens like leather before finally sloughing away. Healing by scarring occurs only when no viable skin is left.
If the tissue cells are dead, there is not much that can be done about them. If you consult your vet and establish that the frostbite is not too serious, one form of treatment is warming the affected tissues. As the blood begins to return to the tissue, it causes swelling (edema), inflammation, and redness.
If the tissues under the skin are damaged, hemorrhage and edema can occur. This is attributed to changes in the permeability of blood vessels and reduced movement of fluid from tissues.
When diagnosing a horse for frostbite, the vet examines the affected areas to check whether there is sensation, whether the tissues are alive, and the levels of blood supply. If the horse cannot feel when pricked with a needle and there is no blood, this indicates that the tissue is dead. During diagnoses for tissue damage after frostbite, studies by vets have found that painful limbs are better than where there is no sensation.
However, frostbite can be aggravated by other factors including the presence of plant toxins and fungal disease that affect the grass. This can lead to blood vessel constriction near the surface of a horse’s body. Once this happens, blood circulation is affected and this increases the chances of the horse losing their tails, ears, or feet. A problem that impairs circulation can increase the likelihood of a horse getting frostbite, even in temperatures that normally would not be considered severe.
Lohmann advises that any dead tissue due to frostbite must be surgically removed if it has not sloughed away. If the blood is still circulating and there is some sensation, the horse needs to be kept indoors and warmed up until the swelling subsides so as to prevent the impaired tissue from freezing again. The horse can also be administered painkillers and antibiotics to treat or prevent infection in the weakened tissues. This needs to be done as quickly as possible. Vets also advise that the horse is given a tetanus vaccination.
Sometimes if warming the tissues is too painful, the horse may need to be sedated. A horse in pain due to frostbites may shake its head (if the ears are frozen) or bite the affected body part. Rubbing the frostbitten area so as to restore blood circulation is not recommended since the compromised tissue can be damaged further. Standing the animal in buckets with warm water and applying warm towels to the feet of the horse can help.
Whereas frostbite is rare in horses, look out for signs of frostbite in your horse particularly if you live in an area that experiences frigid temperatures for long periods. Provide shelter when it rains or if there is snow or ice. In case your horse shows signs of frostbite, get him out of the cold and give your vet a call.
Image credit: Pinterest.com
Disclaimer: Of Horse! and sponsors do not endorse nor validate the accuracy of a blog post. Each article is the opinion of the blogger.