As stated in Cow Comfort and the Effects on Productivity and Profitability, published by John Brouillette and Nancy Spanski for the Dairy Management Program of the Cornell University Animal Science Department (Publication Date 4/29/98):

“Stall design and surfaces are the number one factor that influences cow comfort.”

They continue, “The objective of the resting area is to encourage cows to lie down as much as possible. Research by Metcalf and Rulquin point to the increased blood flow across the mammary gland when dairy cows lie down compared to when standing. The increased blood flow (reported at 25% greater than when standing) results in increased nutritional efficiency and milk production. It’s this point that most directly relates cow comfort to productivity. Cows are designed to eat, lie down, eat, lie down, over and over again. If, cows stand simply because it hurts when they lie down, or it is physically difficult to lie down, the pattern will be broken and she will not consume those last mouthfuls of dry matter that translate into additional milk production.”