Heat stress among dairy cows is a growing problem in the United States as the climate warms and farmers look to increase production from their herds. Now, researchers say farmers can predict which cows are in danger of overheating: the ones that stand for long periods without lying down.Researchers from the University of Arizona and Northwest Missouri State fitted cows with sensors that measured core body temperature and leg sensors that determined whether the animal was sitting or standing. The cows were more likely to stand for long periods when their body temperature rose above 102 degrees Fahrenheit, probably because standing exposed more of their surface area to air, allowing body heat to disperse. But while that may help the cows feel cooler, it ultimately uses more energy than lying down, the researchers said. Their findings were presented last week at a meeting of the American Dairy Science Association. time of oman