Obviously, cold winter weather conditions can impact our cattle. Animals that have acclimated to cold temperatures by growing a sufficient winter coat can usually tolerate low thermometer readings, but… add wind, rain or both to that already cold temperature… now we have what is referred to as “cold stress”.
Cold Stress requires us to pay attention and change things up as needed to avoid unnecessary condition loss.
So, why be concerned if your cows come out of winter too thin?
Reason #1: The thinner the cow, the less likely she is to become pregnant or rebreed successfully.
Reason #2: Skinny cows produce less colostrum, so their calves may not be as healthy or robust.
Understanding Cold Stress
Lower Critical Temperatures
To understand when cold stress would start to occur, research has determined the lower critical temperature (LCT) based on hair coat (Table 1). When temperature drops below the lower critical temperatures based on the animal’s coat condition, the animal would be in cold stress.
Table 1. Lower Critical Temperatures for Beef Cattle
Coat Condition Critical Temperature, Degrees F.
Wet or Summer Coat 59°
Dry, Fall Coat 45°
Dry, Winter Coat 32°
Dry, Heavy Winter Coat 18°
Energy needs of animals (how much feed is needed) are based on effective temperature. Effective temperature includes ambient temperature, wind, and humidity. Table 2 shows the influence of wind speed on the effective temperature that cattle experience.
Table 2. Wind Chill Temperature, Degrees F.
Air Temperature, Degrees F.
Wind Speed -10° 0° 10° 20° 30°
5 mph -16° - 6° 3° 13° 23°
10 mph 21° -11° - 1° 8° 18°
20 mph -30° -20° 10° 0° 9°
30 mph -46° -36° -27° -16° -6°
Cattle producers understand that the animal’s energy needs increase when temperatures drop. The general recommendation is for every degree that the effective temperature is below the lower critical temperature, the animal’s energy needs increase by 1 percent. For example if the effective temperature is 1 degree Fahrenheit, the energy (TDN) needs of a cow with a dry heavy winter hair coat are 17% higher than they would be if the temperature was higher than the LCT.
What are some management options during cold stress?
Offer wind protection. Man-made or natural wind protection is valuable in reducing wind chills and the negative effects of cold environments.
Provide more energy (food). Calculate the additional energy required to maintain the animal’s desired performance and provide it. How the additional energy is delivered can impact the digestive system of the animals. Caution: do not make any rapid diet changes.
Sort into feeding groups. Sort thin cows into a separate feeding group. Thin animals need more nutrients than cows in good body condition.
Supply bedding. Bedding provides insulation from frozen ground.
Provide ample water. Water is critical to ensure adequate feed intake. If water availability is limited, feed intake will be reduced.
Voluntary Feed Intake
Voluntary feed intake is stimulated by colder temperatures. However, in windy conditions animals may have reduced intake due to reluctant to leaving the shelter areas. Table 3 shows the potential estimated intake increases due to changes in temperatures. Temperatures less than 5 degrees Fahrenheit can stimulate feed intake up to 125% of predicted intake; however, digestibility of diet can limit the animal’s ability to increase consumption.
Table 3. Voluntary feed intake of beef cattle in different thermal environments
Temperature Range Intake relative to published values (NRC, 1974)
78 to 60 F Published values in Nutrient Requirements of Beef Cattle
0 to 40 F Intake stimulated 2 to 5%
40 to 22 F Intake stimulated 3 to 8%
22 to 5 F Intake stimulated 5 to 10%
< 5 F Intake stimulated 8 to 25% - intake during extreme cold or
blizzards may vary greatly. Intake of high-roughage feeds
may be limited by bulk
The Bottom Line
Cold winter weather adds stress to animals. Maximize animal nutrition and limit cold stress, both of which help producer’s bottom line.