12/23/2025
Equine Frostbite
Brian S. Burks, DVM
Diplomate, ABVP
Board Certified in Equine Practice
Have you ever felt the chilly, tingly, numbing feeling of your ears, nose, or toes exposed to cold temperatures for too long? If the exposure continues, frostbite can occur.
Frostbite describes the metabolic, cellular, and vascular changes and subsequent tissue injury that occurs when extremities are exposed to extreme cold.
For horses, frostbite is a rare, but real possibility during extreme cold. It is more likely to occur in geriatric, neonatal, and debilitated horses compared to healthy adults. Frostbite often occurs at the ear tips; it is more common in donkeys and mules with longer ears. Foals born in subzero temperatures or windy, wet, cold conditions may have problems with ears, feet, or tail.
Horses have a thick winter coat that protects them, along with the mane and tail to insulate against the cold. More fat is stored under the skin as winter arrives. The horse’s muzzle is richly supplied with blood and can withstand extreme cold. Lower limbs require less circulation than the upper portion of them that has more muscle. The feet have arteriovenous shunts that allow the horse to turn the blood supply on and off, and the dense hoof capsule protects the deeper tissues of the foot.
A horse is healthiest on its feet, moving around. Recumbent animals are at more risk than healthy horses; they can become hypothermic and even freeze to death. Sick and dehydrated horses are more likely to develop frostbite as their circulation is decreased to the extremities.
At very cold temperatures, cell metabolism is inhibited, and dehydration occurs (the air is much more sere). Cells are disrupted by ice crystals, ischemia, and vascular damage. This can be due to prolonged exposure at the higher limits of sub-freezing temperatures or can be only a few minutes when the temperatures become more extreme, especially when the wind chill has reached sub-zero temperatures. Frostbite can occur at temperatures above freezing. Although temperature plays a role, so may other medications or substances that cause vasoconstriction. For example, endophyte infected grass hay has a mold that serves as a toxin causing the vessels to contract, leading to ischemia, which will lead to loss of the ear tips or tail at higher temperatures.
We tend to anthropomorphize and think that our animals cannot be left outside in frigid conditions. Horses are adapted to colder temperatures and utilize piloerection to lift the hair, providing a layer of relatively warm air next to the skin that protects them. Blankets stop this from happening. Equines are thermo-neutral between 20- and 40-degrees Fahrenheit. This means that they are not expending any energy to stay warm or cool.
Horses with blankets in relatively warm barns can also be a problem. If they sweat under the blanket, it can cause the horse to be colder than having no blanket. Wet blankets or bandages can cause hypothermia and lead to frostbite, even at temperatures above freezing, especially if the wind is blowing.
The most common areas affected include the g***s p***s, ear tips, coronet, and heels. The skin becomes pale, followed by reddening and swelling. Skin and hair may be shed later. Occasionally pigment in the skin is permanently lost, and the hair may grow back white. Necrosis and dry gangrene may occur with severe frostbite; the skin blackens. When horses are clipped, especially for medical procedures where the skin is completely exposed, they can become cold or suffer from frost bite. Such horses will benefit from a blanket, even a light one.
In the extremities, there is a tangle of blood vessels where the arteries coming from the body are wrapped closely around the veins returning from the extremities to the core. This anatomy is absent from the rest of the body.
The capillaries that nourish the far-away tissues are between the arteries and veins. They are so tiny and have such a large surface area that pumping warm, core-body temperature blood into them would cool off the entire body.
Horses can protect their lower limbs from freezing by using arterio-venous shunts. These shunts have a valve that is closed most of the time, allowing the arteries to pump blood efficiently into the capillaries and from there back into the veins and back to the heart. When it is extremely cold, these shunts open and divert the arteriole blood directly into the venule and then back to the body, bypassing the capillaries. This shunting also cools down the extremities and conserves body heat. Horses thus effectively control the amount of blood that enters the foot, which minimizes heat loss. Thus, enough blood appears to enter the lower limb to keep it alive, but it is made to withstand very low temperatures. Medically, horses with laminitis are often stood in ice slurries up to the carpus for 72 hours without any adverse effects. This cooling slows metabolism, allowing the cells to maintain homeostasis.
Classification of frostbite is applied after rewarming. It can take three to four weeks before the full extent of the damage can be assessed. Foals are likely to be much worse than adults as they lack fat deposits for insulation, therefore heat loss is greater. Heat loss is much greater in foals also due to a relatively large surface area.
First degree Frostbite: erythema (redness) or white to deep purple and swelling; redness may indicate recirculation has started.
Second degree: Severe edema with papules (solid, raised areas of skin)
Third degree: ischemic necrosis of the skin and subcutaneous tissues. The blisters may be hemorrhagic. This may require amputation/debridement.
Treatment:
1. Shelter the horse from the cold and move into a warmer place. Remove any wet clothing. Look for signs of hypothermia (lowered body temperature) and treat accordingly. Cold ground provides conduction of heat away from the body, so indoors or blankets on the floor are a must. Cover with blankets to prevent heat loss via convection (into the air).
2. If immediate medical help is available, it is usually best to wrap the affected areas in sterile dressings (in humans, remember to separate affected fingers and toes) and transport to a hospital for further care.
3. If immediate care is not available, rewarming first aid may be given. Soak the affected areas in warm (never hot) water -- or repeatedly apply warm cloths to affected ears, feet, or p***s -- for 20 to 30 minutes. The recommended water temperature is 104 to 111 degrees Fahrenheit. Keep circulating the water to aid the warming process. Severe burning pain, swelling, and color changes may occur during warming. Warming is complete when the skin is soft, and sensation returns.
4. Apply antibiotic and steroid cream to the area, followed by dry, sterile dressings. In humans, put dressings between frostbitten fingers or toes to keep them separated.
5. Move thawed areas as little as possible.
6. Re-freezing of thawed extremities can cause more severe damage. Prevent refreezing by wrapping the thawed areas and keeping the person warm. If protection from refreezing cannot be guaranteed, it may be better to delay the initial rewarming process until a warm, safe location is reached.
7. If the frostbite is extensive, give warm water to replace lost fluids. Nasogastric intubation or warmed intravenous fluids may be necessary. It is important to rewarm the ‘core’ temperature while the surface temperature is being raised; the latter may result in vasodilation, and further loss of ‘core’ heat.
Good prognostic indicators are normal colored, pliable skin, and good skin sensation. Poor prognostic indicators include firm, non-elastic skin, and dark blisters.
Do NOT thaw out a frostbitten area if it cannot be kept defrosted. Refreezing worsens tissue damage.
Do NOT use direct dry heat (such as a radiator, campfire, heating pad, or hair dryer) to thaw the frostbitten areas. Direct heat can burn the tissues that are already damaged.
Do NOT rub or massage the affected area. This causes mechanical damage to fragile skin.
Do NOT disturb blisters on frostbitten skin.
Do NOT smoke or drink alcoholic beverages during recovery as both can interfere with blood circulation. That means you or the horse; I have seen people try to give beer or spirits to horses. The St. Bernard does not really carry alcoholic beverages in the container.
In addition to good nursing care, a variety of medications may be appropriate, including flunixin meglumine, acepromazine, aspirin, Pentoxifylline, and broad-spectrum antibiotics, as determined by a veterinarian. Topical aloe vera may be of value several times per day.
Prevention:
1. Remove wet blankets ASAP.
2. Shelter horses from high winds.
3. Provide extra hay.
4. Allow movement to increase blood flow; however, horses turned out on very cold days may not move around much. Give them an area to shelter from wind, rain, and snow.
Call your veterinarian immediately if there is fever, severe discoloration of the body part (as best as you can tell on a horse), or there is drainage from the affected area.
Dr. Brian Burks, Dipl. ABVP is the owner/veterinarian at Fox Run Equine Center, a 24-hour medical-surgical center near Pittsburgh, Pennsylvania. He is board certified by the American Board of Veterinary Practitioners (Equine Practice). This certifies him as an expert in all categories of equine practice. He enjoys the diagnostic and treatment challenges of internal medicine and ophthalmology. Find out more and contact us:
Fox Run Equine Center
www.foxrunrequine.com, [email protected]
724-727-3481
