Assessment of a commercial borescope to evaluate the presence of lesions of digital dermatitis in dairy cows

Digital dermatitis (DD) is a worldwide infectious disease of cattle with high prevalence in dairy herds. It is a painful disease with welfare issues causing economical losses.  Identifying the affected animals is crucial to establish early treatment and evaluate the efficacy of a control strategy. The "gold standard" diagnosis of DD is the direct observation of DD lesions in a trimming chute. However, the use of a trimming chute for daily diagnosis of DD in all cows is not possible. To facilitate DD monitoring between trimming sessions, lesions could be identified in the parlor during milking. Therefore, we evaluated the use of a commercial borescope in a rotary milking parlor. Our hypothesis was that a borescope is an adequate alternative to evaluate DD lesions between trimming sessions. Our objective was to assess the sensitivity (Se), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV) of a borescope for the diagnosis of DD in the milking parlor as compared to direct observation in a trimming chute, and to quantify the agreement between both techniques.