Dairy Barn. A dairy barn may be a free stall building, but that is not necessary. The roof design must allow for venting to release heat and moisture. This creates a comfortable environment for cows, who then produce more milk. During the winter period, milk production can fall by 10 percent if cows have to stand or lie in mud. The barn or holding yard requires concrete pads for cattle to escape the mud and wet conditions. If cows are presently tethered then this tie system can accommodate a modern dairy. The dairy barn can be composed of the following areas for: milk cows, dry cows, heifers, milk parlor including holding area, return lane, and milk room with a small office space.