Detection of phylotypes from digital dermatitis lesions and effect of different phylotypes on lesion size.

Bovine digital dermatitis (BDD) is a contagious infectious disease which causes lameness in dairy cows. It has a multifactorial etiology which is not yet fully understood but spp. seem to play a significant role in development of BDD lesions. This study evaluated the presence of phylotypes commonly associated with BDD ( and , in four farms different areas in Iran. Single biopsies were taken from 113 Holstein cows with active BDD lesions (scored according to size) on the farms and polymerase chain reaction assays used to detect 16S rRNA nucleotide fragments of three BDD phylotype groups: '''', '''' and '''' (now ). Over 95.00% of samples were positive for at least one of phylotypes, with 89.00%, 91.00 %, and 66.00% of samples were positive for and , respectively Out of the 113 samples, 60.00% were positive for all three phylotypes, the detection of was positively associated with detection of both and . No association between lesion size and phylotypes identified was found but there were significant differences between farms in the proportion of each phylotypes identified. Further research is required to establish the factors influencing the proportions of individual phylotypes, especially at the farm level.