Recent weather conditions it have been rough for man and beast alike. Sunday’s weather was snow and rain mixed, it has been very wet, very cold and often both outside.  These conditions are tough on the cattle, especially if they cannot stay dry and out of the wind.

Jim Neel, University of Tennessee Extension Beef Specialist, recently sent out the following article with information for adjusting rations to help the cows through tough winter conditions:

Dr. Neel’s examples use hay, and many farmers in Wisconsin also feed, hay, but corn silage and other feedstuffs are commonly used to, and the key to remember here is that the cows nutritional requirments (mainly energy, but also protein etc.) are increasing by the percentages given and you need to adjust your rations accordingly with the feeds that you use in your situation to adjust the ration accordingly to meet those increased needs.

If it is dry and cold with no wind, the cow’s critical temperature is 32 degrees Fahrenheit.

Generally, if the environment is dry and cold and the temperature has dropped to 25 degrees, the feed provided should be increased 7.0%. How is this calculated? This is straight-forward. If the cows are being fed 25 lb. of hay per day, the feed fed should be increased 7.0% This rule of thumb has been utilized for several decades to make adjustments in the cow’s feed needs.

1. The hay being fed prior to the drop in temperature amounts to 25.0 lb. per day.

2. The temperature drops 7 degrees below the cow’s critical temperature. (Thirty two degrees – 25 degrees equal 7 degrees.)

3. The daily feed should be increased 7.0%. (1.0 % for each degree below 32 degrees.)

4. How much extra feed is needed? The cows were being fed 25 lb. per day and need to be increased 7.0%. The feed now needed totals approximately 27.0 lb. per day (26.75 lb. per day).

However, during the winter feeding period, there will be several times that the wind will be “blowing” which changes the feed needs more so than being dry and cold.

Following is an illustration of calculating feed needs with a “wind chill” temperature and the cows have a dry winter coat.

1. Again, the cow’s critical temperature is 32 degrees Fahrenheit.

2. The environmental temperature with wind chill is 8 degrees Fahrenheit.

3. The effect of the cold can be calculated by subtracting 8 degrees from the 32 degrees which equal 24 degrees.

4. As in the above illustration, extra feed needed is equal to the difference in degrees, so the feed should be increased 24 percent.

5. The cows are being fed 25.0 lb. of hay per day. It should be increased 24 percent to adjust for the wind chill.

6. In this, illustration, feed the cows 31 pounds of feed per day.

The winter months also bring lots of precipitation. Cows with a wet hair coats have the greatest feed requirement. Cows that are experiencing rain have a “critical” temperature of 59 degrees Fahrenheit. With a wet hair coat, the feed requirements double for each degree change in “windchill” factor. For each degree change, the feed requirement changes 2%. In the preceding illustration, the “wind chill” was 8 degrees.

Following is an illustration of calculating the feed needs with a “wind chill’ of 8 degrees and rain.

1. The cow’s critical temperature is 59 degrees. Subtract the “wind chill” temperature, 8 degrees, from the critical temperature for rain, 59 degrees. Fifty nine degrees Fahrenheit – 8 degrees (wind chill) = 51 degrees

2. The feed needs for the cow would be 2 x 51 = 102 percent increase or 25.5 lb. of feed for a total of 51 pounds.

In the world of cow-calf producers, very few weigh the hay that is fed. When it is suggested that feeding 25 or 31 or even 51 pounds of hay per cow per day we know that no one is going to go out on a cold, windy day and weigh the allocation of hay. The preceding is based on science of changing energy needs under varying weather conditions. Therefore, the following are suggested:

  • When a cold front is coming, make plans to increase the amount of high quality hay to the herd. If feeding two big bales a day, plan to feed more, maybe 3 bales a day or 5 bales every other day.
  • Bacterial digestion of hay in the rumen releases heat that warms cattle. Higher quality hay releases more heat of digestion. If a cold front is approaching, try to feed higher quality hay.
  • If a cold, wet period is approaching where it would be difficult for hay alone to meet the energy needs of the cow herd it may be necessary to provide both an increase in hay plus a forage-friendly supplement.
  • Supplementation advice is best when based on a forage test. Sometimes a little extra protein, possibly provided by a commercial block or tub, can be beneficial. Other times,a blend of energy / protein concentrate feeds might be better.
  • Monitor body condition. This is the best method for assessing the success of feeding programs on a daily / weekly / monthly basis.

Cow-calf producers should stay informed of the weather conditions and make adjustments in feeding programs. Cold weather and rain increase the need for feed. Inadequate feed intake will result in reduced performance,

Source: WI Beef Information Center