Public perception of dairy cows is of animals enjoying tranquil lives in a bucolic setting grazing in lush pastures during the day and sleeping in straw-bedded barns at night. Reality, however, is quite different. Three out of four dairy cows in the United States never graze in pasture, and a significant proportion are not provided routine access of any kind to the outdoors. Those who are housed outside are usually confined to a large, barren dirt lot that is hot and dusty in summer and cold and muddy in winter.