An In-House ELISA for Treponema Antibodies in Bulk Milk as Part of a Monitoring Tool for Claw Health in Dairy Herds

SIMPLE SUMMARY: Digital dermatitis (DD) is a painful infection of the skin at the coronary band of the claws, a major cause of lameness in dairy cattle and associated with several Treponema species (spp.). Clinical inspection of the feet is the common way to diagnose the disease, but is laborious. There are no simple diagnostic tools, which makes it difficult to monitor DD prevalence in a herd. Therefore, we developed, validated and implemented a Treponema antibody detecting ELISA for use in bulk tank milk. A weak relation between clinical scores of claws with the results of ELISA in individual milk samples was found. When using bulk milk, a clear increase in the ELISA response was observed when mean clinical scores of the claws in the herd were higher. Using the results of the Treponema ELISA in bulk milk, herds with a low or high number of cattle with DD could be distinguished. This ELISA is now being used in a claw health monitoring program for dairy cattle in the Netherlands. This helps farmers to obtain insight into the level of DD in their herd and is helpful to improve claw health in dairy cattle. ABSTRACT: Digital dermatitis (DD) is a painful inflammation at the coronary band of the claws, a major cause of lameness in cattle and associated with infections with several Treponema spp. Clinical inspection of the feet is the best way to diagnose DD, but this is laborious and stressful for cattle. A simple diagnostic tool was developed to monitor DD prevalence at the herd level. An antibody ELISA based on antigens from four different Treponema spp. has been developed and validated in two field studies. In one study, bulk milk and individual milk samples of seven dairy herds, of which clinical claw scores were obtained, were tested. In the second study, bulk milk was tested from 110 herds of which clinical scores were obtained. A weak correlation between clinical scores of cows and the ELISA results in individual milk samples was observed. The ELISA response in bulk milk was higher in herds with higher mean clinical scores. Using the ELISA results in bulk milk, herds with a low or high proportion of cattle with DD lesions could be distinguished. This ELISA is useful to obtain insight into the DD status at the herd level, and is nowadays being used in a claw health monitoring program for dairy cattle in the Netherlands.