Does or ewes with ears cropped due to frostbite damage at birth are not an uncommon sight on Northeastern goat and sheep farms. Although the condition is not life-threatening, it can lead to interesting explanations in the show ring. In severe winters, frostbite can be farm more serious, affecting newborns’ feet and tails and teats of dairy does.
Under normal conditions, blood carries oxygen throughout an animal’s body to keep all tissues healthy. However, if an animal’s body temperature suddenly starts to drop, its blood vessels constrict to keep the animal alive by diverting oxygen-rich blood away from extremities (feet, tail, ears, legs) and toward vital organs (liver, heart, brain, etc.). Lack of blood and oxygen damages tissue cells in deprived extremities, in which ice crystals begin to form. Blood clots may also develop, further reducing circulation to damaged tissues. If the condition persists long enough, dry gangrene (tissue death) can occur, leading to the tissue damage and amputations associated with frostbite.
Loss of body heat and body temperature (hypothermia) is hastened by wind chill and wetness; sufficient nutrients and body fat can help protect against heat loss. Newborn kids and lambs are particularly vulnerable to hypothermia. They are born with very little body fat and are unable to regulate their temperature. A meal of warm, high-quality colostrum is required as soon as possible as a source of life-giving calories and passive immunity against disease.
Rubbing wet and chilled neonates with towels and warming them can save their lives. However, this treatment is not advisable for frostbite damage. Instead, rapidly thaw frost-bitten extremities in warm water at about 101 to <105°F. This is a little warmer than the inside of one’s wrist, or about the temperature of a warmed bottle of milk or colostrum. It is then very important to dry affected extremities before they can freeze again. Do not rub frostbitten tissues or apply direct heat >105°F because this can damage fragile tissues even more.
Air-drying extremities is easy if the newborn has been taken to a warm facility for thawing frostbitten tissues. However, in a frigid barn, it is more challenging. Wrapping extremities in a warmed towel or using a well-padded heating pad are two options. Otherwise, if the only choices are a hair dryer or heat lamp, keep the dryer’s blowing temperature low, ensure the heat lamp is well anchored, and keep both a safe distance from affected tissues. Frostbitten areas are very susceptible to sunburn or heat lamp burn. The key is to warm the around the tissues rather than the tissues themselves.
Do not bandage the affected areas because this could interfere with circulation. Ears, especially long ears, are most commonly affected. However, in severe subzero temperatures, newborns in a drafty barn can suffer frostbite to tails and legs. If frostbite is believed to be more extensive than an ear or two, thoroughly thaw and dry legs using the above procedures. Hind legs are more susceptible than front legs because most newborn kids and lambs keep their front legs warn by tucking them under their bodies while lying down.
Frostbitten areas are very vulnerable to re-freezing. If frostbite damage to legs is suspected, try to house affected newborns at above-freezing temperatures for several days and prevent rigorous exercise. Continue to warm the affected area(s) in 101 to <105°F water twice daily for the new several days. Lanolin, zinc oxide ointment, or aloe vera may be applied gently to affected skin. After a few days, hair on affected areas may shed. Ear tips may shrivel or swell; eventually, all or part of an ear margin may die and slough off. If legs are affected, they will swell after a few days and hair and tissues will begin to fall off. When leg damage is suspected, consult a veterinarian to determine if IV fluids or other medications are indicated to manage pain, block the release of inflammatory mediators, and help increase blood circulation.
If tissue starts to slough, consult a veterinarian to determine if spraying a liquid bandage onto the affected areas will help protect sensitive skin, and whether antibiotics are indicated.
Immediate amputation of frostbitten tissue is not advised because there may be only severe tissues damage, not gangrene. The concern is that if present, gangrene can extend farther up the leg than initially determined. It can take up to six weeks for a distinct line of demarcation between living and dead tissue to appear, so delaying until the full extent of tissue damage is obvious is prudent. There seems to be very little pain when frostbitten tissues slough off. If foot and leg tissue below the cannon bone is lost, the animal may develop calluses and get around fairly well on a “naked foot.” Depending on where the break is, degree of animal comfort, and farm situation, a decision will need to be made to euthanize the animal, grow it to slaughter weight, or keep it as a pet.
Dr. Pamela Karner of Starland Veterinary Services in N.Y. emphasizes that “by the time frostbite has been identified in an animal, it is too late to do much. Prevention is the key; wet and cold combined are deadly.” When kidding or lambing in winter, make sure barns are suitable for anticipated weather conditions. If temperatures and wind chill result in subzero outside temperatures, increase the amount of deep bedding and frequency of birthing checks to ensure newborns are dried rapidly after birth, especially on their extremities. A few cropped ears are inevitable when sheep and goat farming in cold climes, but keep frostbite from causing more serious damage.
tatiana Stanton, Cornell Univ. Small Ruminant Extension Specialist
Thank you to Mariah Gentry, Class of 2016, Cornell University College of Veterinary Medicine, Ambulatory and Production Medicine for her excellent information about frostbite. Thank you to Dr. Mary Smith, DVM, Professor of Ambulatory and Production Medicine, College of Veterinary Medicine, Cornell University, Ithaca, New York for her pictures and additional insights.