RESUMEN
Digital dermatitis is a major cause of lameness in many dairy herds and represents a detriment to milk production, reproductive efficiency, productive lifespan and welfare. The purpose of this study was to evaluate the therapeutic use of a Serpens species bacterin in a dairy herd known to have a significant prevalence of lameness due to digital dermatitis. Seventy-six mature lactating Holsteins were enrolled in this study. Group 1 (n=38) received three injections of a Serpens species bacterin at four-week intervals (weeks 0, 4, and 8) while group 2 (n=38) received only adjuvant. Blood samples were obtained prior to the first injection at week 0 and again at week 12 to evaluate antibody responses. Locomotion and digital dermatitis lesion measurements were performed at weeks 0, 12 and 18. Although Serpens-associated antibody titers increased from week 0 to 12 in vaccinated cows; the prevalence of digital dermatitis, the percentage of cows identified as clinically lame and the average width of digital dermatitis lesions did not differ from week 0 to 12 or from week 0 to 18 between groups. The results of this study indicate a lack of any clinical efficacy associated with vaccination in this herd, although inoculation with the bacterin did stimulate a measurable antibody response.