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As
in past months, I continue to talk to producers who will run out of hay
before the grass greens in the spring. I always end each conversation
with the statement that in a year with reduced forage, we need a mild
winter. As I am writing this article it is 12° F outside and we are
expecting a high today of 43.
With
the beginning of cold weather, I wanted to look at some issues
concerning the relationship between temperatures and feeding demands of
brood cows. I would suggest that you closely monitor your cattle this
winter. When the weather is cold and wet, cows need extra feed to just
keep warm.
A
cow needs to eat more roughage in cold weather to give her the calories
for heat energy. If she doesn’t have enough roughage, the pounds will
melt off of her as she robs body fat to keep warm. High quality feeds
are not as efficient as roughage in producing long term heat because
cows will readily gobble up the feed and stand around shivering.
If
a cow has a good winter hair coat, she will do fine in dry weather until
temperatures drop below 32°. With a wet hair coat due to rain and snow,
this critical temperature can rise to as high as 59°. At these points,
she will require an increase in feed intake to produce the body heat and
stay above her lower critical temperature level. Lower critical
temperature is defined as the lower limit of cattle comfort during cold
weather.
When
cows drop below this level, an increase in feed is required to maintain
the cows’ current body status. When figuring lower critical
temperature, you must also take into account the fact that wind and
moisture makes effective temperature lower than thermometer temperature.
You must always figure the wind-chill factor when arriving at amount of
degrees below a cow’s critical temperature point. Critical temperature
for any cow or calf will vary according to hair coat, moisture, age,
size, amount of body fat, length of exposure, and wind. Cold stress is
also less severe if the storm is brief, compared with the chill and
stress of continuous bad weather.
Critical
Temperature for Beef Cows
Coat
Description
Critical Temperature (F)
Summer Coat or wet
59 Degrees
Fall
Coat
45 Degrees
Winter
Coat
32 Degrees
Heavy Winter
Coat
18 Degrees
A
rule of thumb to compensate for cold is to increase the amount of feed
(energy source) by one percent for each two degrees of cold stress. For
thin cows, cows with poor hair coats or a wet hair coat figure a 1
percent increase for each degree of temperature drop. Example A: A cow
that is wet will require 9% more feed at 50 degrees than that same cow
at 59 degrees. Example B: A cow exposed to a wind chill temperature of
28 degrees on a dry day will require 4% more feed than the same cow at
32 degrees.
Many
producers overlook the effects of cool, wet weather when supplementing
cattle. I would suggest that you become familiar with the critical
temperature of your cowherd and make feeding decisions based upon this.
By doing this, your cows will remain in better condition and will be
more productive as they calf this spring. If I can help you determine
your critical temperature level, or can help you develop a feeding
program around your available forage, please call me. I can be reached
at 256-947-7886 or jimmyh@alafarm.com.
I
hope that each of you had a Merry Christmas and look forward to a new
year with the promise of good prices and prosperous crops.
Jimmy
Hughes is AFC’s animal nutritionist.
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