Cows need more nutritional energy in colder weather. The rule of thumb is that a cow’s energy requirements increase 1% for each degree the wind chill is below the 32° F lower critical temperature (LCT) for cows with a dry winter hair coat.
Glenn Selk, Oklahoma State University Extension cattle specialist, suggests a common-sense approach is to make a smaller increase in energy requirements during wet, cold weather and extend the increase into improving weather to help regain energy lost during a storm. He says cows consuming 16 lbs. of grass hay/day and 5 lbs. of 20% range cubes can be increased to 20 lbs. of grass hay/day plus 6-7 lbs. of range cubes during the severe weather event. Extending this amount for a day or two after the storm may help overcome the energy loss during the storm and do it in a manner that doesn’t cause digestive disorders.