Managing Cold Stress in Calves During Winter
During the first few months of life, calves and youngstock experience ongoing physiological changes that create consistent internal stress. External factors, especially cold weather, can intensify that stress significantly.
With winter approaching, it’s essential to understand the challenges young calves face during colder months and how to manage them effectively.
What Is Cold Stress in Calves?
Like all warm-blooded mammals, calves work to maintain a stable body temperature. This process is easiest when they are within their thermal neutral zone (TNZ).
The TNZ is the temperature range in which calves do not need to expend extra energy to stay warm or cool down. For calves under one month of age, the TNZ ranges from 50°F to 77°F.
When temperatures drop below 50°F, calves must use additional energy to maintain body temperature. That extra energy must come from somewhere. During periods of increased stress, supplemental energy and electrolyte support may help calves maintain hydration and energy balance.
Below are key nutritional and management strategies to help reduce cold stress and keep calves healthy and growing throughout the winter months.
Nutritional Strategies to Manage Cold Stress
1. Feeding Temperature
Milk should ideally be fed just above a calf’s body temperature, between 103–105°F.
Even in well-organized operations, cooler ambient temperatures can cause milk to be delivered below the calf’s body temperature. When calves consume cool milk, they must expend energy to warm it internally.
Additionally, colder milk may not fully stimulate closure of the esophageal groove. This can allow milk to enter the immature rumen. Because the rumen is not fully functional in young calves, milk may ferment improperly, leading to digestive upset.
2. Fat Level
Increasing the fat concentration of your milk replacer during winter months is another effective method of managing cold stress. Higher-energy milk replacer programs designed to support maximum gain can help calves meet their elevated maintenance requirements during cold weather.
Higher fat levels increase the caloric density of the milk replacer, providing additional energy to meet maintenance needs. However, balance is critical.
Protein and fat should be maintained at a minimum ratio of 1:1, with protein ideally exceeding fat. Excessive fat levels can cause digestive upset, leading calves to go off feed — an undesirable outcome during cold weather.
3. Volume
Another strategy is to feed calves greater milk volumes.
Providing increased volume delivers more nutrients and calories. This can be achieved by increasing the amount per feeding (for example, 3 quarts instead of 2) or by adding an additional feeding (3 feedings instead of 2).
However, this approach may not always be practical. Many operations are limited by bottle size, and labor constraints can make additional feedings difficult.
4. Percent Solids
Increasing percent solids is similar to increasing volume, as it raises calorie and nutrient intake. This helps calves meet their higher maintenance energy requirements during cold weather.
This method is often more practical than increasing volume because it allows you to maintain your existing feeding schedule.
Management Practices to Reduce Cold Stress
1. Newborn Calves
Most dairy operations have calves born year-round. During colder months, newborn calves are frequently covered in amniotic fluid, which increases heat loss.
Wiping newborn calves with a clean towel helps dry the coat and improves heat retention. This practice also mimics the dam licking the calf, stimulating blood flow to the extremities
2. Bedding
Clean, dry bedding provides essential insulation against cold temperatures.
Straw is widely considered one of the best bedding options for winter conditions. Adequate bedding depth is important. Ideally, calves should be able to nest deeply enough that their legs are not visible when lying down.
3. Blankets
Calf blankets offer an additional layer of warmth and protection from wind and cold air.
Although they add expense, they can be beneficial during extreme conditions. If blankets are used, straps should be adjusted regularly to accommodate calf growth.
4. Fresh Air
While concerns about drafts are understandable during winter, proper ventilation remains essential.
Pens or hutches without adequate airflow can create an environment where pathogens thrive. Poor ventilation may lead to the very illnesses producers aim to prevent.
Preparing Your Calves for Winter Success
Winter presents unique challenges for young calves. Without proper nutritional and management adjustments, growth and overall health may be compromised.
Careful attention to feeding temperature, nutrient density, bedding, ventilation, and newborn care helps ensure calves remain healthy and continue growing despite cold conditions.
Ready to Strengthen Your Winter Calf Program?
If you’d like to evaluate your winter feeding strategy or adjust your milk replacer program to better manage cold stress, reach out to your Esmilco team. We’re here to help you prepare your calves for a healthy and productive season ahead.
