Research indicates energy requirements for maintenance of beef cows with a wet hair coat is much greater. Cows exposed to falling precipitation and having wet hair coats are considered to have reached the LCT at 59° F. In addition, the requirements change twice as much for each 1° change in wind-chill factor -- with the energy requirement actually increasing 2% for each degree below 59° F.
This amount of energy change is often impossible to accomplish with feedstuffs available on ranches. In addition, this amount of energy change in the diet of cows accustomed to a high roughage diet must be made very gradually to avoid severe digestive disorders.
Therefore, the more common-sense approach, says Glenn Selk, Oklahoma State University Extension cattle specialist, is to provide a smaller increase in energy requirements during wet cold weather and extend the increase into improving weather to help regain energy lost during the 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 in a manner that doesn't cause digestive disorders.