It’s safe to say winter has finally arrived in western Michigan with temperatures now hanging steadily in the 30s during the day and cooling off to well below freezing at night. With cooler temperatures comes a need to implement additional calf management practices to ensure calves arrive with the best opportunity for a healthy and productive start to life.
A young calf has a thermoneutral zone between 55-77 degrees F. Any temperature above this range and calves need to dissipate heat to stay cool. Below that range, they need to conserve heat to stay warm.
In fact, when the ambient temperature drops between 25-55 degrees F, energy requirements may increase 32 percent; even more in colder temperatures. If calves can’t meet these increased energy requirements, they will mobilize body fat reserves and lose body condition. Cold-stressed calves also experience suppressed immune systems and become more prone to illness.
Increase Caloric Intake
The best way to provide additional energy to calves in cold weather is to increase their caloric intake. Adding a third feeding per day is an excellent strategy. Another option is increasing total milk volume fed, typically by one-third. If feeding milk replacer, increase the volume of powder in the same amount of water to create a more energy-dense meal, but don’t exceed 20 percent total solids. To ensure accuracy, utilize a scale to weigh milk replacer.
If milk is too cold, calves need to utilize energy to heat it up, so feed it at around 105 degrees F. Fat supplements can also help with keeping warm. Add them to milk or milk replacer at 2-6 oz. Calves also appreciate consistency so schedule evenly spaced feedings at the same times each day.
In times of cold stress, calf starter intake rates are often elevated, so provide high-quality calf starter, fresh and free of fines, beginning on day three. Pre-weaned calves need warm water immediately after each feeding beginning on day three, while weaned calves need an unlimited supply of water. Like milk, if water is too cold, calves must expend energy to warm it and often will not drink. Water intake is positively correlated with starter intake, rate of gain and is necessary for hydration and digestion.
Keep High-Quality Housing
Within one hour of birth, newborn calves need to be thoroughly toweled dry, provided four quarts of high-quality colostrum and moved into the warming box. Keep warming boxes around 60 degrees F. After 12-24 hours, calves are free to leave the warming box, but not without their calf jacket. As they grow, keep jackets adjusted for proper fit and prioritize the youngest animals.
As ambient temperature rises above freezing, older calves may no longer require jackets. Check them frequently and remove jackets from any calves that are sweating. When moving from the warming boxes into hutches or group housing, calves need sufficient bedding to nest and stay warm and dry. Bed hutches should be bedded with at least 60 lbs. of straw each and, in all housing setups, calves should be able to nest deeply enough that two-thirds of their legs are buried in straw. Bedding should also pass the “kneel test.” Kneel in bedding for 30 seconds. If it passes the kneel test, your knees should come out dry. A base layer of sawdust or shavings can help absorb moisture and keep straw bedding drier.
Calves are exceptionally prone to respiratory challenges, so make proper ventilation a priority. Housing facilities should be free of drafts and provide fresh air. The air should never feel or smell stale. Hutches are designed for draft-free ventilation, and group housing barns should have proper curtain designs to prevent drafts, but promote air exchange. Positive pressure ventilation tubes have become increasingly common in calf barns and can improve winter and summer air quality.
Always remember the importance of a knowledgeable, dependable maternity pen and calf care staff and strong calf care protocols in helping calves start off on the right hoof.