Most spring-calving beef cows are now in their third trimester, or they will be calving soon in late January or February. Since these months also tend to bring on the most volatile and extreme cold periods, cold stress can add another level of needs to their energy requirements.According to K-State Research and Extension beef systems specialist Justin Waggoner, cattle producers need to provide their spring-calving herds with proper nutrients and energy during extreme cold temperatures; the focus should be the use of high-energy forages when available.Cold stress factorsCattle are most comfortable in their thermoneutral zone, in which they are neither too hot nor too cold and do not have to expend additional energy to regulate their temperature, said Waggoner, who is located at Kansas State University’s Southwest Area Extension Office. Factors such as wind chill and humidity also play a role in a cow’s comfort level.“Cold stress increases maintenance energy requirements for a cow in good condition by about 1 percent for each degree below the lower critical temperature,” he said.The temperature at which an animal experiences cold stress can vary, depending on whether or not the animal is able to stay dry and if it has a sufficient winter coat, he added.