Newborn calves may
require their own version of a
receiving blanket, used to protect babies from cold and drafts. The
difference is they’re called calf blankets.
Made of
insulating-type fabrics such as wool, polyester blends and insulating foams,
calf blankets fasten in place with straps, Velcro and/ or ties.
The obvious reason to
use calf blankets is to keep calves warm in cold weather. But what’s cold to
a newborn calf? There’s a temperature range, called thermoneutral, where
the amount of body heat produced by a calf is balanced by body heat losses.
For an 85-pound newborn calf, this range is about 50 – 78 degrees, assuming
she’s dry and in a draft-free environment. As temperatures fall below 50
for an extended period, a calf has to burn extra energy to maintain her body
core temperature.
How heat escapes
No matter what the weather, heat can escape
from a calf in four ways:
1.
Evaporation. Heat from her
body is used to
evaporate water
primarily on her skin and hair coat. This loss is easy to solve at birth.
After dams lick off their calves, finish the drying and fluff up her coat.
If calf housing
during the first month of life doesn’t provide a dry place that protects a
calf from rain and snow, a water repellant blanket can keep her drier.
2. Conduction.
Most calves less than a week old spend 90% of their time lying down. Is the
bedding dry or wet? Direct contact with wet straw results in three times as
much heat loss (conduction) as contact with dry wood shavings.
A moisture repellant
blanket can slow down conduction heat losses through damp bedding.
3. Radiation.
This occurs when heat is transferred through the air from a warm object –
the calf – to a cold one – concrete or snow.
Radiation losses are
reduced if calves can lie down some distance away from the cold object.
A blanket provides an
insulating barrier to reduce heat moving away from the calf’s body.
4. Convection.
These losses occur when air passes over the calf’s body. Draft-free housing
where a calf can snuggle down into a bed of straw minimizes convection
losses.
