Economics of diseases causing dairy cattle lameness at herd level

In a cross-sectional study, performed between October 2002 and April 2003 on 55 Danishdairy herds with 6161 predominantly Holstein Friesian cows the prevalence of 9 hoof lesionswas determined.All test day yields (TDY) of kg Energy Corrected Milk (ECM) in the lactation of diagnosiswere recorded. For the purpose of including hoof lesions in a decision support model anattempt was made to aggregate the lesions into digital dermatitis (DD), other interdigitaldiseases (OID, infectious diseases other than DD) and hoof horn diseases (HHD, related tometabolic disorders and trauma). A division was made based on the stage of lactation inwhich the lesions were diagnosed; during the first 100 days in milk, between day 101 and200 and between day 201 and 305. Associations between the presence of hoof lesions attrimming and milk production were analyzed by linear mixed modeling at the cow level,clustered within herd. The data of primiparous cows was analyzed separately from themultiparous cows. Based on the associations between TDY and the individual lesions aggregated into HHD,this aggregation as initially planned could not be justified and was therefore not maintained.For OID the value of early diagnosis was apparent; an early diagnosis and early treatment(<101 DIM) was associated with either a positive value or a value less negative compared toa diagnosis and treatment in late lactation (201-305 DIM). This pattern was not as clearlypresent for the other lesions.