Severe Winter Weather Newborn Calf Care

DR. TERESA L. STECKLER

SIMPSON, ILL.
   This winter has become a broken record – warm temperatures followed by deep plunges.  However, this week in southern Illinois we received a thick layer of ice. Calving during these times of weather extremes required extra vigilance to ensure survival of those calves and hopefully prevent future health problems.
   When calves are born under less-than-desirable conditions – freezing rain, cold temperatures, and windy conditions – it is important for cattlemen to be concerned about hypothermia.
   There are two types of hypothermia: exposure (gradual) and immersion (acute). Exposure hypothermia is the steady loss of body heat in a cold environment through respiration, evaporation and lack of adequate hair coat, body flesh or weather protection. This type affects all classes of livestock but particularly affects young, old and thin animals.
   Immersion hypothermia is the rapid loss of body heat due to saturated hair coat in a cold environment. Immersion hypothermia is often brought on during birth when the calf is born saturated with birthing fluids. Other causes 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.
   Faced with a cold environment, the body tries to defend itself in two ways: shivering, to increase muscle heat production, and blood shunting, to reduce heat loss by diverting blood flow away from the body extremities to the body core.
   Mild hypothermia occurs as the body’s core temperature drops below normal (approximately 100° F for beef calves). In the early stages, vigorous shivering is usually accompanied by increased pulse and breathing rates. A cold nostril and pale cold hooves are early signs that blood is being shunted away from the body’s extremities. In the case of a newborn calf, severe shivering may interfere with its ability to stand and suckle. This sets the calf up for severe hypothermia. Erratic behavior, confusion and clumsiness are all signs of what producers often call “dummy calf.” These are signs of mild hypothermia.
   Severe hypothermia results as the body temperature drops below 94° F. Shunting of blood continues, manifesting cold and pale nostrils and hooves due to poor oxygenation of the tissues near the body surface. Decreased circulation also results in a buildup of acid metabolites (waste products) in the muscles of extremities. After the shivering stops, it is replaced by muscle rigidity. The pulse and respiration begin to slow as the body core cools to 88° F.
   Below core temperature of 94° F, the vital organs are beginning to get cold. As the brain cools, brain cell metabolism slows, resulting in impaired brain function. The level of consciousness deteriorates from confusion to incoherence and eventual unconsciousness. Below 86° F, signs of life are very difficult to detect and the calf may be mistaken for dead. The pupils of the eyes will be dilated and fixed. The pulse may be undetectable. Occasional gasps of respiration at a rate as low as four or five per minute may be the only clue that the calf is still alive. Heart failure may be the actual cause of death.
   The immediate concern is returning the calf’s core body temperature to normal (100° F for newborns). Maintaining the normal core body temperature is a secondary objective. For years, producers have used floor board heaters of pickup trucks, submersion of wet calves in a warm bath, placing calves next to the heater in the house, or placing the calf under a heat lamp.
   Warming and drying boxes have also been used over the years with limited success. Some producers refer to them as “death boxes.” Most early warming boxes were a four-foot by three-foot plywood box where the hypothermic calf could be placed to dry and warm. Heat sources were often a heat lamp or propane heater. There was usually no fan to circulate warm air. Ventilation was not considered in construction. As the hair coat dried, the moisture raised the humidity within the box, setting the calf up for pneumonia. Oftentimes, the calf would be left unattended and suffer from heat stress or scorching.
   The use of a thermometer is highly recommended. Often, a calf will not appear to be hypothermic. However, upon taking its temperature you may realize that the calf’s body temperature is below normal. This is often brought on by dystocia (slow births) which may have put the calf in a hypoxic state (lack of oxygen). A hypoxic calf is slow to dry off and nurse, allowing hypothermia to set in.
   Feed the hypothermic calf warm colostrum as soon as possible to speed recovery and increase the probability of full recovery. It contains energy, protein, fat and vitamins, plus antibodies to protect newborns against disease until their own immune system is totally functional. Breathing the warm air from the calf warmer along with consuming colostrum will warm the calf from the inside out and provide the needed energy to overcome the trauma it just went through.
   The dam’s colostrum is optimal. The next best options are frozen, stored colostrum or one of the commercial colostrum substitutes. Commercial colostrum substitutes need to contain a minimum of 100 grams of immunoglobulin G (IgG) per packet. IgG is an antibody absorbed through the calf’s small intestine and provides protection against disease-causing pathogens.
   Severe hypothermic calves can be revived and saved. However, they often are set back from the experience, and their body defense system can be compromised. This sets the calf up for pneumonia, scours and other calfhood problems. The incidence and severity of hypothermic calves can be reduced through preventative measures.∆
DR. TERESA L. STECKLER: Extension Specialist, Animal Systems/Beef, University of Illinois