EDITOR’S NOTE: This is the second of two parts on frostbite in cattle.
Often when a newborn calf suffers frostbite, he is also hypothermic — body temperature below normal. If his core temperature is too low he may die. Getting him warm is just as important as thawing out frozen extremities like ears, tail and feet.
“If you find a near-frozen animal out in the cold, such as a young calf, warming it up gently is usually recommended, not overdoing it with too much heat at once,” says Dr. Katharina Lohmann, of the Western College of Veterinary Medicine in Saskatoon, Saskatchewan, Canada. “If you find a newborn out in the cold it’s important to bring it in, warm it up and make sure it’s dried off.”
Getting some energy into the animal with proper nutrition (such as colostrum for a newborn) is also very important. Warm colostrum (warm to the touch but not hot) can help warm the calf from the inside, as well as provide the extra calories for generating body heat. Colostrum contains twice the fat calories of regular milk.
“Severely hypothermic animals may require more intensive therapy such as warmed IV fluids or warm oral fluids if they can tolerate the latter,” Lohmann says. “It can sometimes be difficult to separate hypothermia from frostbite. You often see both problems together.”
It’s always advisable to take the animal’s rectal temperature. If it’s subnormal you need to be treating for hypothermia as well as potential frostbite.
“Rapid thaw at moderate temperatures (100 to 105 degrees F.) is often recommended,” she says. “ We generally use hot-water bottles and heat lamps and closely monitor rectal temperature so the animal doesn’t overheat. Overheating is potentially harmful.”
Getting the damaged skin too hot can add to the frostbite damage. Some of the hot boxes with heat lamps can actually become too hot.
Warming an animal too much or too quickly, such as putting a very cold calf into hot water (such as in a hot tub), may cause heat injury, and may also be life threatening in cases of severe hypothermia. In a cold animal, blood has been shunted away from the extremities and into the body core, to try to keep the internal organs warm enough to keep them functioning. If you suddenly put the cold animal into hot water this can be too drastic a change. It drives the cold from the outer body surfaces into the body core. If the heart is chilled too much (cold shock), it will stop, and the animal will suddenly die. Ranchers attempting to thaw frozen calves in a bathtub with water too warm sometimes discover this phenomenon.
It’s better to start out with lukewarm water, then gradually warm it up to body temperature (101 degrees). Keep in mind that humans who suffer hypothermia or whose temperature is drastically lowered for surgery are always brought back to normal temperature slowly.
A safe way to warm a severely cold calf is to use warm IV fluids and warm air to warm the air he’s breathing. You need to warm the innermost part of the body as swiftly as you warm the outside. If it’s a cold, wet newborn, you also need to be drying him at the same time. Wet calves have a harder time warming up. Towels and hair driers can help speed the process.
If the calf was merely chilled and gets his body temperature back up to normal within an hour or so, and he has a belly full of colostrum and is now dry, he can probably go back out with mom. If he suffered frostbitten ears, tail or feet, however, and those extremities are compromised, he needs to stay indoors (perhaps with mom in a stall in the barn, with good bedding) until he is fully recovered and the frostbitten tissues are no longer swollen and painful. Otherwise they are more vulnerable to cold stress and freezing again.