When winter winds pick up, young calves feel it first. A drop in temperature means their small bodies must work harder just to stay warm — diverting energy away from growth and immune function. For producers, those few extra degrees can mean the difference between thriving calves and those struggling to gain.
Understanding how cold stress affects nutrition and daily gains is key to keeping calves healthy through the season. With the right preparation — from adjusting milk programs to monitoring water access — winter doesn’t have to slow growth or compromise herd health.
Understanding Cold Stress in Calves
Newborn calves have limited energy reserves — only about 2–4% of their body weight is fat (Barrett, 2021). When temperatures drop, they burn extra calories to maintain body heat, leaving fewer nutrients for growth. That means their nutritional needs rise significantly during cold weather.
Because calves are born as non-ruminants, they depend almost entirely on milk for energy during the first few weeks (Drackley, 2008). Their rumen isn’t yet active, so milk solids are digested in the abomasum and small intestine. Until starter intake increases, the composition and quality of milk or milk replacer are critical for maintaining growth and immune strength.
Boosting Nutrition for Winter Growth
Raising the plane of nutrition is one of the best defences against cold stress. Increasing milk volume or feeding frequency ensures higher calorie intake to support warmth and weight gain.
Feeding milk or milk replacer equal to 15–20% of a calf’s body weight daily is recommended to meet higher winter energy demands (Welboren et al., 2020). This can be achieved by adding an extra feeding or slightly increasing the amount per feeding. A fat supplement or higher-fat milk replacer can further boost calorie density without adding much labour.
These simple adjustments support stronger growth rates, higher average daily gains, and smoother transitions through the pre-weaning phase.
Monitoring Whole Milk Quality
Whole milk remains an excellent feed option year-round but requires extra attention in winter. Pasteurization reduces bacterial risk, especially when feeding waste milk. The standard plate count should remain below 100,000 cfu/ml to be considered safe for calves.
Milk solids typically average around 12.5%, though this varies with lactation stage and cow health (Welboren et al., 2020). A BRIX refractometer offers a quick way to assess solids. If milk quality drops, a milk balancer can help restore nutrient content and consistency. Research by Glosson et al. (2015) found that supplementing milk with balancer products improved average daily gains and overall body weight in pre-weaned calves.
However, solids above 15% can increase the risk of digestive upset, scours, and dehydration (Azevedo et al., 2023), so regular testing and careful mixing are essential.
Don’t Forget Water
Even in winter, fresh water access is vital. Calves with free-choice water drink more milk, gain faster, and convert feed more efficiently. Wickramasinghe et al. (2019) found that calves provided free drinking water consumed 300 grams more milk and achieved greater feed efficiency before weaning.
Offer warm water in small amounts several times a day to encourage drinking and help maintain body temperature. Water supports digestion and reduces the risk of scours, especially when temperatures fluctuate.
Preparation Pays Off
Cold stress can quickly affect growth and health, but proactive management helps calves thrive through the winter. Adjusting milk programs, using milk balancers wisely, and maintaining water access all support stronger, healthier calves — ready to perform when they enter the milking herd.
