Table 1.
A summary of each protocol evaluated during the five experiments.
Table 2.
Macroscopic Lesion Scoring System.
Fig 1.
A summary of each protocol within the five experiments.
The pen designations denote whether animals were housed within the same pen or separate pens and the letters may designate different pens across experiments. The number of feet qualified refers to the number of feet enrolled in each protocol that retained a wrap throughout the length of the study and did not receive topical or systemic antibiotics during the trial period. The induction rate is the percentage of feet that had a macroscopic lesion score of 7 or greater. The brackets denote statistical significance between groups with alpha = .05 and a correction for multiple testing.
Fig 2.
Lesion Grades for each Macroscopic Lesion Score.
Histopathology score summary from each of the macroscopic scores. As biopsies were only taken from feet with visible lesions, the majority of the lesions scores were 6 or greater. Several lesion scores of 4 and 5 were included in the <6 category. The grade 1 category encompassed all biopsies identified as normal bovine skin. Grade 2 lesions were described as hyperkeratosis, acanthosis with surface hemorrhage and erythrocytic crusts. Grade 3 lesions were described as segmental localized necrotizing to necrosuppurative epidermitis with individual cell necrosis, ballooning degeneration of epithelial cells, necrotizing vasculitis, intralesional bacteria consisting of delicate spirochetes, bacilli, and coccobacilli.
Fig 3.
Representative DD Lesions from Experiment 5.
Digital Dermatitis lesions on day 28 following wrap removal. Photos A and B represent control calves and photos C and D represent lesions that scored 10 using the induced lesion scoring system.
Fig 4.
The number of sensitive feet for each day on trial for experiment 5.
Feet were wrapped and abraded on day 0, inoculated on day 3 and wraps were taken off on day 28. The minimum objective measure for a sensitive foot was that a calf held the foot off the ground while standing.
Table 3.
The Number of Lame Feet for Each of Protocol.
Fig 5.
Grade 3 Digital Dermatitis Histopathologic Changes.
5A shows the characteristic changes of a Grade 3 lesion with necrosis of surface epithelium inflammatory infiltration, ballooning degeneration of epithelial cells, and colonizing bacteria within surface lesions. 5B shows more defined intra-lesional spirochetes within inflammatory loci when stained using W/S silver staining.