Associations between digital dermatitis lesion grades in dairy cattle and the quantities of four Treponema species

AbstractDigital dermatitis (DD) presents as painful, ulcerative or proliferative lesions that lead to bovine lameness affecting economic efficiency and animal welfare. Although DD etiological agent(s) have not been established, it is widely accepted that DD is a polymicrobial disease significantly associated with species ofTreponema and the non-linear disease progression may be attributed to interactions among infecting bacteria. We postulated the morphological changes associated with DD lesion grades are related to interactions among infecting species ofTreponema. We developed a novel species-specific qPCR that can identify the absolute abundance of the four of the most common species ofTreponema in DD,T. phagedenis,T. medium,T. pedis andT. denticola, in a single reaction. We found species abundance and the number of distinctTreponema species present is higher in active, ulcerative lesions than in healing lesions, chronic lesions, and DD-free skin. Treponema spp. were present in both DD-free skin and M3 lesions following treatment with oxytetracycline. We have also found positive correlations amongT. phagedenis,T. medium andT. pedis indicating they are significantly more likely to be found together than apart and their absolute quantities tend to increase together, a relationship which is not present withT. denticola. Further, we foundTreponema, particularly viableT. denticola, in lesions 5  days post treatment with oxytetracycline (M3). Our findings suggest that pathogenic...
Source: Veterinary Research - Category: Veterinary Research Source Type: research