Cold weather is stressful for calves. Those that are exposed to the cold are predisposed to respiratory tract infections (pneumonia). Appropriate nutrition and a fresh supply of water will do a lot to help them overcome stress. When calves are not fed adequately in cold temperatures, they don’t grow as quickly since they are using their energy to keep warm instead.
If calves are shivering after feeding they are cold and not being fed adequately. A good rule of thumb is to increase the amount of milk replacer by 2% for every degree the temperature falls below 5°C.
Ensure calves have enough bedding to keep them dry and warm. During the fall, winter and spring months, ensure you are bedding with straw, which will help to reduce a calf’s heat loss. To determine if a calf has enough straw, do the “kneel test”.
The Kneel Test
If you are unsure whether or not bedding should be changed, kneel on the bedding for 20 seconds. If your knees get wet, the bedding should be changed or added to.
The comfort zone for a calf over one week of age is around 15–25°C, and 13°C–20°C for animals younger than that. This is the temperature at which calves can maintain their own body temperature and grow.
The colder it gets, the more energy a calf needs to maintain heat and to keep growing. This means you must adjust your feeding program as the weather changes. A good rule of thumb is to increase the amount of milk replacer by 2 per cent for every degree the temperature falls below 5°C. When the outside temperature is 5°C, 4 litres/day at the concentration of 125g/l is starvation for a calf.
Additional Feed Requirements Needed by Calves During Cold Weather
Source: Adapted from Nutrient Requirements of Dairy Cattle. Seventh Revised Edition. National Research Council, 2001, and Nutrient Requirements of Beef Cattle. National Research Council, 1996.
|Temperature°C (°F)||50–kg calf, <3 weeks,additional milkreplacer* (L)||50–kg calf, >3 weeks, additional milkreplacer* (L)||75–kg calf,additional milkreplacer (L)||Weaned calves, calf starter or grain mix kg (lb.)|
|0°C (32°F)||1.8||0.9||1.4||0.4 (.9)|
|–10°C (14°F)||2.7||1.8||2.7||0.8 (1.8)|
|–20°C (–4°F)||3.5||2.7||4.1||1.2 (2.6)|
|* 20% protein, 20% fat milk replacer mixed at 125 g/L|
*Provided the calves that are dry, well bedded and kept out of drafts. If they are not, the feed requirement will be even higher in cold temperatures.
Dr. Sam Leadley of Attica NY has compiled charts with calf weights, milk replacer formulations and outside temperatures. Visit this link and check to make sure you are feeding your calves enough, especially in the winter. Metric charts can be found near the bottom, as well as charts for pasteurized milk. If you are feeding good quality whole milk, there are charts to ensure you are feeding according to temperature.