Dairy cows need clean, well-ventilated buildings called barns in which to live. Barns provide comfortable shelter for cows. Barns are also built to make it easier for farmers to care for their cows. The size and design of the barn often depends on the size of the dairy cow herd and the weather conditions. A barn is carefully planned so that dairy cows are kept comfortable, clean, and safe. Barns are cleaned daily to ensure a healthy environment. Barns include areas to treat sick cows, birth calves, and breed cows.