Page 9 - MWC 09-9-2021s

Fall Calving in Hot Weather The Midwest Cattleman · September 9, 2021 · P9

By Mark Z. Johnson
After a mild summer, the fresh water is vital. If calves
heat continues just as fall don’t have access to streams
calving herds will begin see- or ponds and are therefore
ing calves hit the ground. dependent on water tanks,
With this in mind, we focus make sure the tank sits low
on the challenges faced in fall enough and water levels in-
calving herds in hot weather. side are high enough for baby
The primary challenge is the calves to have access.
impact high temperatures Drovers
have on newborn and young
calves.
While fall calving is often
easier than calving in the
winter and early spring,
when temperatures are
high it can create unhealthy
conditions for calves. The
thermoneutral zone for a
young calf is between 50 – 77
degrees Fahrenheit. Like-
wise, cows calving in hot
weather are more likely to
become overheated and ex-
hausted sooner in the pro-
cess than a cow calving in
cooler temperatures. This
can lead to prolonged calving
and more stress on both cow
and calf. When fall calving
is taking place during high
temperatures, beware of the
following:
•Heat stress is actually
harder on young calves than
cold stress. When calves are
heat stressed they lose appe-
tite, eat less and are quicker
to become dehydrated.
•Newborn calves have an
immature “thermostat” and
accordingly have more prob-
lems regulating body tem-
perature during weather ex-
tremes.
•Shade and fresh water
are critical. In addition to
milk, calves need more fresh,
cool water in hot weather to
prevent dehydration, keep
their rumen functioning
correctly and maintaining
health and appetite.
•Effects of heat stress on
the dam can also negatively
impact calves by reducing
the transfer of passive immu-
nity and subsequent weaning
weights.
•Black hided calves are
more susceptible to heat
stress than calves of lighter
shades.
Critical “Best Practices”
for fall calving herds include
providing ample shade for
calving cows and the young
calves. Shade and plenty of