It's for newborn calves too-and nesting can decrease the incidence of respiratory disease in calves. During their first week of life, calves spend 80 percent of the day lying down. During Week 2, this time only decreases to 75 percent. Now factor in that newborn calves have little body fat and their comfort zone is between 50°F and 78°F and the need for creating a nest for a calf becomes evident. Studies have shown that creating a nest where the calf's legs are covered by the straw not only helps keep calves comfortable but decreases the incidence of respiratory disease. You can test the effectiveness of the bedding yourself by kneeling down on it. If your knees feel cold after a few minutes, the calf will feel cold too. If bedding materials are less than desirable or don't allow for nesting, calf blankets can be used to keep calves warm.
Reprinted with permission from the Professional Dairy Producers of Wisconsin