Cold weather can change a calf’s nutritional needs long before temperatures reach freezing. Young calves have limited insulation and lose body heat quickly, leaving less energy available for growth when temperatures fall below their lower critical temperature.
Preparing calves for winter means looking beyond the thermometer. Bedding, moisture, ventilation, nutrition and the timing of management interventions all influence how well calves cope with cold conditions.
The transition into winter also provides an opportunity to review herd health protocols and prepare for periods when respiratory disease may become a greater concern.
1. Recognize When Calves Are at Risk of Cold Stress
A calf’s lower critical temperature (LCT) is the point below which it must expend additional energy to maintain body temperature. The threshold varies with age, size, nutrition, hair coat and environmental conditions.
For calves younger than three weeks, the LCT is approximately 59°F. For calves older than three weeks, it is closer to 50°F. These are estimates rather than universal cutoffs because wind, moisture, bedding and other environmental conditions influence heat loss.
Dr. Curt Vlietstra, senior professional services veterinarian with Boehringer Ingelheim, recommends paying attention to seasonal transitions, particularly when daytime temperatures fluctuate substantially from overnight lows.
“Try to have more of an awareness, especially in the places where you have a big change in the weather,” he says. “The daily high and the overnight low can differ substantially, creating conditions that warrant closer attention to respiratory disease.”
Vlietstra says temperature swings of approximately 25°F can create a greater respiratory disease concern. Producers should use these transitions as a prompt to review calf housing, bedding and feeding programs before colder conditions become persistent.
Smaller dairy breeds, including Jerseys, may warrant particular attention, while beef-cross calves may tolerate some temperature fluctuations better than straight dairy calves. Neither group is immune to cold stress.
2. Reduce Heat Loss Through Housing and Bedding
Keeping calves dry and protected from direct wind is one of the most effective ways to reduce heat loss. Deep, dry bedding allows calves to nest down, trapping insulating air around their bodies. Wet bedding and damp hair coats reduce that protection.
As overnight temperatures decline, Vlietstra recommends reviewing basic housing protections before conditions become more severe.
“Make sure you’ve got adequate bedding, out of the wind,” he says. “If they’re outside, make sure they’re dry.”
Ventilation remains important during winter. Closing barns to retain heat can allow moisture, ammonia and airborne contaminants to accumulate. The goal is to maintain fresh air exchange without creating drafts at calf level.
Calf jackets can provide additional insulation, particularly for young calves, but they should supplement rather than replace appropriate housing and bedding. Always check that jackets remain dry, fit properly and are adjusted or removed as temperatures rise.
3. Adjust Nutrition to Meet Higher Energy Needs
When temperatures fall below a calf’s LCT, maintenance energy requirements increase. If feed intake does not rise accordingly, less energy remains available for growth and immune function.
Vlietstra advises preparing to provide additional energy as colder weather approaches, including considering changes to the feeding program.
“Most of the good milk replacer companies have additives that can be used to provide additional energy,” he says, referring to products intended to support calves during cold weather. He suggests adding “a little bit more fat, a little bit more energy.”
For young milk-fed calves, options may include increasing the volume of milk or milk replacer, adding a feeding or using an appropriate higher-energy formulation. Producers should follow product directions and maintain the intended milk replacer concentration rather than simply adding more powder to the same volume of water.
Older calves can obtain more energy from starter as rumen development progresses. Clean, unfrozen water remains important to support starter intake even in cold weather.
The timing and duration of cold conditions also matter. A planned adjustment is more useful when colder weather is expected to persist, with housing improvements and calf jackets helping during shorter periods of fluctuating temperatures.
4. Avoid Stacking Stressors During Cold Weather
Cold stress is one of several demands that can challenge a calf during environmental transitions. Moving, regrouping, changing rations and vaccination can add further demands, making the timing of management interventions worth reviewing.
Vlietstra summarizes the principle simply: “It’s really about not layering stress.”
When practical, separate vaccination from other major management changes, such as moving calves or changing rations. Vlietstra recommends considering whether calves are already dealing with other challenges when selecting vaccination timing.
This does not mean delaying necessary vaccination or compromising disease protection. Vaccine timing should reflect herd disease risks, product directions, calf health status and the practical opportunities available for handling animals.
Vlietstra also challenges the perception that vaccination protocols are “set it and forget it.”
“One of the things I struggle with is this perception,” he says. “Certainly protocols should be redone on an annual basis.”
He suggests that increasing to seasonal vaccine protocol reviews could be even more beneficial. Seasonal reviews can help veterinarians determine whether existing protocols remain appropriate as environmental conditions and disease pressure change. Some farms may benefit from adjusting timing, while others may have limited flexibility because of labor or handling requirements.
Colostrum management deserves attention during the same review. Vlietstra emphasizes that the fundamentals remain consistent throughout the year: provide high-quality colostrum promptly after birth, ensure calves receive an adequate volume and deliver it at an appropriate temperature. Seasonal changes in colostrum volume or feeding practices may justify closer monitoring, but cold weather does not replace the need for sound protocols in every season.
5. Monitor Disease Trends and Reassess Herd Health Protocols
Cattle often conceal signs of illness, making early detection difficult. Waiting until respiratory disease is obvious can delay intervention and allow problems to progress.
“Cattle are crazy and they’re created to hide their weaknesses and illnesses from predators,” Vlietstra says.
Veterinarians can help producers look for changes in treatment rates, clinical disease patterns and diagnostic findings. An increase in respiratory treatments should prompt a closer look at housing, ventilation, nutrition, vaccination coverage and other management factors.
Thoracic ultrasonography can also help veterinarians identify respiratory disease and refine treatment decisions when used as part of an appropriate diagnostic approach. Vlietstra highlights the importance of evaluating whether management interventions are moving health outcomes in the right direction.
If a farm adjusts feeding, housing or vaccination timing in response to cold weather, treatment records, growth performance and diagnostic findings can help determine whether the changes are beneficial.
Cold-weather preparation does not require every farm to adopt an entirely different health program. It requires veterinarians and producers to recognize changing conditions, identify vulnerable animals and make targeted adjustments before problems escalate.
By combining appropriate housing, adequate energy intake, careful timing of management interventions and closer monitoring of herd health data, veterinarians can help producers protect calf health and maintain growth through winter.
