Regional studies indicate that udder cleft dermatitis (UCD) and hock lesions (HL) are common among Swedish dairy cows and that the prelavence varies between herds. The severity of the lesions varies but it is likely that the lesions cause pain and discomfort for the cows. It is also possible that UCD and HL are connected to other diseases like mastitis and digital dermatitis (DD), and many have negative effects on milk production and economy. The overall aim is to improve prevention of these animal welfare problems. We also want to understand associations between UCD/HL and other diseases and the importance of UCD/HL for dairy production. Specific aims are to investigate the national prevalence of UCD and HL in dairy herds with loose housing systems, to identify risk factors associated with prevalence, initiation and recovery of UCD and HL, to evaluate associations between UCD/HL and mastitis and DD, and to evaluate effects of UCD and HL on milk production and culling.