Although the official start to winter is now upon us, we have already experienced several weeks of cold weather. In sub-freezing temperatures, calves (and all mammals) are motivated to maintain internal body temperature. Thermal stress can increase calf morbidity and mortality and reduce rates of growth. Focusing on calves’ increased needs in the winter months can provide the best opportunity for success.
    Maternity and newborn calf housing: Combatting cold stress in calves starts in the calving pen. Calves are born with a minimal amount of body fat reserves. The calf’s small body mass relative to external surface area results in rapid loss of body heat. Clean, deep-bedded straw helps, but wet calves lose heat quickly to the environment.
    Towel drying a newborn calf aids in fluffing its hair coat. This works as an insulator by creating a boundary between the calf’s body and the chilly ambient air. Pay attention to drying the ears as this will help reduce the risk of frost damage. Warming boxes work well to finish the drying process and keep calves warm during the first 12 hours after birth. However, calf boxes must be kept very clean to reduce disease pressure. They should be cleaned and sanitized between calves.
    Calves receiving supportive warming therapy after birth will have less stress and, as a result, will likely have greater efficiency of immunoglobulin absorption from colostrum feeding.
    Calves should be moved out of the warming box into the next calf facility by 24 hours of age. Again, deep-bedded straw is a great option for insulating effects. Calves placed into hutches and cold barns should be furnished with calf jackets for approximately the first three weeks of age. Adjust the jacket so it continues to fit as the calf grows.
    Nutrition considerations: The first goal is to satisfy calves’ maintenance requirements. Increasing the plane of nutrition to combat cold stress is of primary importance. Caloric demand for maintenance increases as the temperature decreases below 55 degrees Fahrenheit. The more energy a calf must use to maintain body temperature, the less that is available for growth. This calf is more susceptible to mobilizing body fat reserves and amino acids. Additionally, energy is pulled away from the immune system, making calves more prone to diseases.
    Strategies to increase energy intake during cold stress include altering the amounts and timing of milk feeding. Milk volume is often increased by about one-third. Shifting from two to three times daily feeding will also increase milk intake. Supplemental fat can also be added to milk feeding. Be aware this addition can impact total solids in the milk. Work with you calf nutritionist and advisors to decide which strategies fit your operation best.
    Water intake is critical to starter consumption and rumen development. Offer warm water to calves after the milk feeding. Pails may need to be dumped prior to the next feeding in extreme cold conditions.
    Additional management considerations: Excessive calf handling should be avoided during really cold days. Consider holding off on pen moves or vaccinations if possible as these events create addition stress on the animals and thus demand more energy. Another unintended consequence of cold weather is greater fluctuation in milk temperature at feeding. The ideal feeding temperature is 105 degrees Fahrenheit. You may need to get creative in how to maintain this feeding temperature. Moving milk replacer powder into a warm room can make a significant difference.
    Finally, monitor and track calf growth and health. This will help identify bottlenecks and troubleshoot challenges. Excellent management during winter will allow calves to overcome cold stress and continue to grow at target rates.
    Barry Visser is a nutritionist for Vita Plus.