While the drier air many calf rearers are enjoying is a welcome change after a challenging autumn, the arrival of sub-zero temperatures brings a fresh set of concerns. Top of the list is cold stress. Young calves are particularly vulnerable in cold conditions, as they have limited fat reserves and an underdeveloped ability to regulate body temperature. When calves are forced to burn valuable energy simply to stay warm, growth rates, immune function, and overall performance can quickly suffer.
The good news is that cold stress is largely manageable. With a few straightforward management adjustments, calves can remain comfortable, healthy, and on track—even during the harshest winter weather.
Start from the ground up
Bedding is one of the most effective tools we have to combat cold stress. Increasing bedding levels with clean, dry, deep straw allows calves to “nest” properly. A well-bedded calf should be able to lie down with its legs tucked underneath and its body insulated from the cold floor. This nesting behaviour significantly reduces heat loss and helps calves conserve energy.
Equally important is shed design and airflow. Take time to check for draughts at calf level. Fresh air is essential for respiratory health, but cold air blowing directly onto calves can undo all the benefits of good bedding. The goal is clean, controlled ventilation that removes moisture and stale air without chilling calves. If you’re unsure whether your shed strikes the right balance, it may be worth revisiting ventilation principles or reviewing solutions such as Galebreaker systems to improve airflow without increasing draughts.
Nutrition: fuel for warmth and growth
Cold weather increases a calf’s energy requirements, so nutrition must keep pace. Speak with your nutritionist about whether milk volumes or concentrations should be adjusted during prolonged cold spells. A calf that is short on energy will prioritise staying warm over growth, leaving it more susceptible to illness.
Water access is often overlooked in winter, but it remains critical. Calves should always have access to clean, fresh, unfrozen water, as water intake supports rumen development and feed intake, even at a young age. Consider pre fillings spare buckets before the frost sets in to have on hand if taps or automated watering systems freeze overnight.
Create a warm micro-climate
Small changes within the pen can make a big difference. Creating sheltered lying areas—such as placing straw bales at the back or sides of pens—helps calves escape draughts and retain body heat. These warm micro-climates encourage calves to rest properly, which is vital for growth and immune function.
For calves under three weeks of age, calf jackets can be a very effective tool. Used correctly, they reduce heat loss and help young calves cope during their most vulnerable period. In particularly cold sheds, infrared heaters can also be useful. These systems heat the calf directly rather than warming the air, making them both effective and energy-efficient when used strategically.
Planning pays off
Cold weather is simply part of winter farming, but cold stress doesn’t have to be. Regular checks of bedding, airflow, nutrition, and calf comfort can prevent small issues from becoming costly problems. A proactive approach not only protects calf health but also supports better growth rates, fewer setbacks, and stronger animals going into spring.
With a bit of forward planning and attention to detail, calves can stay warm, comfortable, and thriving—even when the thermometer dips well below zero.