Getting to grips with the etiology of digital dermatitis

Digital dermatitis (DD) is a painful disease of the feet of intensively managed cattle.

DD is a leading cause of lameness, associated with large economic losses due to decreased reproductive performance and loss of milk production.

The rapid response to antibiotic treatment of DD lesions strongly supports a bacterial cause, but it is still unknown which bacterium/bacteria are the cause of the disease, although many studies suggest bacteria of the genus Treponema.

So far, typical symptoms have emerged only after experimental transmission through inoculation with fresh scrapings from DD lesions, while inoculation with pure cultures of bacteria isolated from DD lesions has not produced any or only very mild symptoms.

Our main goal with this study is to use metagenomics to identify which bacteria are present in cattle claws with different stages of the disease, to cultivate bacteria from these DD lesions, and to characterize the isolated bacterial strains with respect to genotype (genome sequencing and bioinformatic studies) and phenotype (enzymatic activity, antibiotic resistance, and aggregation with other bacterial species/strains).

The knowledge and material generated in this project are crucial pieces to conduct well-founded infection studies in order to elucidate the etiology of the disease, and to be able to proceed with the development of diagnostic and epidemiological methods, treatment strategies and possible vaccines.