The welfare of dairy cows is improved in relation to cleanliness and integument alterations on the hocks and lameness when sand is used as stall surface.

Lying down is a highly prioritized behavior in dairy cattle, and previous studies have shown that the type of stall surface has a great effect on the health and welfare of the cow. The objective of this study was to examine the effect of stall surface (rubber mats, mattresses, or sand) on cleanliness, integument alterations on the hocks, lameness, and milk yield of loosely housed dairy cows. Thirty-seven Danish dairy farms with Danish Holstein-Friesian cows were included in the study, and 2,593 cows were examined. Twelve of the farms used rubber mats, 17 of the farms used mattresses, and 8 used sand as the stall surface. Cows housed in facilities with sand in the freestalls were at lower risk of being dirty, had fewer integument alterations on the hocks (e.g., hairless patches, lesions, and swellings), and were less likely to be lame. The cows in facilities with sand in the freestalls also had a significantly higher milk yield compared with cows housed in facilities with mattresses. No differences in milk yield were found between cows housed in facilities with mattresses and rubber mats. Cleanliness, integument alterations, lameness, and milk yield are important indicators of cow welfare; this study showed that, compared with other stall surfaces, sand had a positive effect on these indicators. We therefore conclude that the use of sand as a stall surface is associated with improved welfare.