Robert Corbett, nutritionist and veterinarian with Dairy Health Consultation in Utah, reminds calf-raisers to evaluate their feeding program for impending cold weather. Calves need more energy in cold weather to compensate for increased demand to maintain core body temperature, in addition to fighting off disease. It’s conceivable that a calf’s energy requirement may more than double when temperatures drop below 0 degrees F.
Research has shown that at a temperature of 39 degrees F, a calf has a 32 percent increase in energy requirement compared to a calf raised at 50 degrees F.
If extra energy is not supplied, a calf will utilize its own fat reserves for energy. Fat deposits in young calves are usually not very large and, once they are used up, the calf starts breaking down muscle protein for heat production and energy.
During extreme weather conditions, the solids content of milk replacer can be increased to 15 to 18 percent, says Corbett. Concentrations above 18 percent may tend to cause an osmotic diarrhea. “I have not had any problem with increasing the solids content up to the 18 percent level,” he notes.
Several supplements are available that contain 60 percent fat, which can be added to whole milk or milk replacer to increase its energy density. A third feeding may be necessary in order to provide the energy level required by the calf to maintain its body temperature without losing weight.
Corbett says that it is especially important to warm the milk replacer or whole milk to 105 degrees F before feeding so the calf does not have to expend extra energy to bring the milk up to body temperature after ingestion.