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OSU Extension

College of Food, Agricultural, and Environmental Sciences

January 4, 2016 - 8:12am -- Anonymous

Although weather has been mild through December, at some point true winter weather is going to get here. Winter weather has an impact on livestock nutritional requirements, especially livestock that winter outside.  In a recent OSU Extension beef cattle newsletter, John Grimes, OSU Extension Beef Production specialist addressed some winter weather conditions that livestock producers need to be aware of.  Below is an excerpt from that article:

Most cow-calf producers understand that winter weather can pose challenges for them to meet the nutritional needs the cow herd. Changes in temperatures and moisture (rain, sleet, snow, ice, etc.) can significantly impact the daily nutritional needs of the beef cow. The stage of gestation or lactation of the cow certainly impacts her daily needs regardless of the season.

In a recent issue of Oklahoma State University’s Cow-Calf Newsletter, Dr. Glenn Selk reminds producers how weather conditions impact the nutritional needs of the beef cow. He points out that researchers have used the rule of thumb that cows’ energy requirements increase 1% for each degree the wind chill is below the 32 degree F lower critical temperature. For example, assume that we have a wind chill of 10 degrees F. The cow’s energy requirement would then increase by 22 %. If a cow typically eats 20 pounds of high quality grass-legume mixed hay per day, they would then require 24.4 pounds per day.

Dr. Selk also stated that research has indicated that energy requirement for maintenance of beef cows with a wet hair coat is much greater. Cows that are exposed to falling precipitation and have the wet hair coats are considered to have reached the lower critical temperature at 59 degrees F. In addition, the requirements change twice as much for each degree change in wind-chill factor. In other words, the energy requirement actually increases 2% for each degree below 59 degrees F. Using the same wind chill of 10 degrees F as in the previous example, the cow’s energy requirement would then increase by 98 %.

This kind of energy change is not possible by simply feeding more of the same type of feedstuffs. If you have higher quality hay, feed more of that. Also consider supplementing with grain for more energy but make changes gradually to avoid digestive issues. It would be wise to make smaller changes in the diet at the time of weather-related stress and continue any increases when the weather stabilizes to compensate for any energy deficiencies the cow may have experienced.

Hopefully you have a good handle on the quality and quantity of the forage you have stored for the winter feeding period. If you have not performed a laboratory analysis on the different types of hay that you will be feeding, it is not too late to get this done. If you do not obtain a forage analysis, target your perceived higher quality hay to groups with the highest nutritional demands. First-calf heifers in their last trimester and calving are at the highest risk for nutritional deficiencies and should receive the highest quality feeds. Third trimester and calving mature cows should be prioritized next for better feedstuffs. Bred, dry mature cows in mid-gestation and in adequate body condition are candidates for lower quality feedstuffs.