It’s that time of year again. Cold weather is approaching, and keeping every newborn and young calf healthy might be challenging. Wind and snow can add stress to even the healthiest of calves.
How Cold is Too Cold?
Calves have a zone in which they are comfortable, not too warm or too cold. This thermoneutral zone is the range of temperature in which a calf uses no additional energy to maintain its body temperature. For a newborn Holstein calf, this zone is between 50 and 78 F (10 to 25 C). Any temperature higher or lower will mean that the calf is burning reserve energy to maintain core body temperature, all of this at the expense of growth. As an example, a one-month-old calf’s thermoneutral zone ranges from 32 to 78 F.
When it gets cold, calves need more energy to stay healthy and gain weight. Adjust the milk replacer and calf starter feeding programs to cover the increasing energy needs of calves in cold weather. Research shows that calves housed at 25 F require approximately 30 percent more energy for maintenance. This number will increase as the temperature decreases.
A best management practice is to feed liquids (milk and water) at body temperature, for a calf that would be about 102 F. For example, if the milk replacer you fed was at 65 F the calf will warm it up to her body temperature of 102 F. That energy used to heat up the milk came from the calf’s body resources. Don’t forget that water improves feed intake and helps develop the rumen in your calves. Observe drinking patterns and feed volume to match the calf’s desire to water.
Dry, Clean, <\n>Draft-Free Housing
Calf housing has to be clean, dry and free of draft. Proper bedding increases insulation from the earth or concrete underneath the calf. Bedding when added to a hutch or pen has to be clean — free of soil, pathogens and mold. This easily can be assessed visually. Bedding materials which include sand, straw, corn stalks, paper, wood shavings and sawdust have to be dry. Once the bedding is already placed in the hutch or pen, use the “knee-drop” to test for dampness. You should be able to remain on your knees for 15 seconds or longer without having damp knees. Calves can lose heat rapidly if bedding is wet. Don’t forget, as more energy is used for maintenance, less will be available for growth and immune functions. Provide calves a place to lie down away from drafts. Dry plentiful bedding provides an insulating stable air environment and will encourage calves to lie down decreasing body heat loss in the cold environment.
In colder winters, waterproof calf coats can also help decrease cold weather stress. The “Canadian Journal of Veterinary” research (1989; 53:275-278) reported a 52 percent increase of overall animal insulation on calves that wore coats and that were housed in -22 to 0 F. Calf coats should be dry and cleaned regularly.
Don’t forget that a calf’s coat should be dry and clean as it is its barrier to the environment and insulation. Newborn calves should have ample time to dry before being moved in a hutch and these have to be located in dry areas.
Calves are the future of your herd and taking care of them at a young age will decrease costs throughout the animal’s lifetime, allowing for more profitability in your operation.
Editor’s Note: Ximena del Campo is a Penn State dairy Extension educator based in Lancaster County.