Cold weather during spring calving season creates a risk of calf loss due to hypothermia, but South Dakota State University Extension specialist Tracey Renelt says early intervention can save valuable calves. The leading causes of death during this 24-hour period are dystocia and hypothermia. Hypothermia occurs in two forms — exposure, or gradual, and immersion, or acute. Exposure hypothermia is the steady loss of body heat in a cold environment through respiration, evaporation and lack of weather protection. Immersion hypothermia is the rapid loss of body heat due to a wet, saturated hair coat in a cold environment. Immersion hypothermia often occurs after the birthing process because the calf is born saturated with uterine fluids. Other causes of immersion hypothermia of young calves may include being born in deep snow or on wet ground, falling into a creek, or being saturated from heavy rains followed by chilling winds, Renelt says.
Mild hypothermia occurs when a calf’s core temperature drops below normal, which is about 100° F. Body temperature below 94° F results in severe hypothermia, and below 86° F signs of life become difficult to detect and the calf can be mistaken for dead. Use a thermometer to identify and determine the degree of hypothermia. Difficult births frequently can contribute to hypothermia, as the calf’s weakness makes it slow to get up and nurse. Returning the calf’s core body temperature to normal is the immediate priority. Ranchers over the years have used dry towels or calf blankets to rub calves dry and increase their temperature. Warming calves inside a truck or next to a heater in the house, by submerging wet calves in warm baths, or by placing the calf in a warming box all are effective. Feeding the hypothermic calf warm colostrum as soon as possible helps warm the calf from inside and increases the probability of full recovery. Once the calf has regained its normal body temperature and is completely dried off, it should be returned to its normal environment. Early intervention can save even severely hypothermic calves, but Renelt says, these calves could have compromised immune systems and should be watched closely after recovery.