Evaluation of a biocide footbath solution in the occurrence and healing of digital dermatitis lesions in dairy cows: A clinical trial

The objective of this study was to evaluate the effect of the implementation of different footbathing practices using a new biocide solution (Pink-Step™, Qalian, France) in the healing and the occurrence of bovine digital dermatitis (bDD) lesions. The investigation was conducted through a controlled within cow clinical trial in which the hind feet of cows from each farm were allocated either to the control group or to a moderate (MR) or (IR) intensive footbath-regimen groups. The trial involved 1036 cows (2072 feet) from 10 dairy farms located in western France where bDD was endemic. Split-footbaths were placed at the exit of the milking parlor of each farm, allowing the biocide to be administered to one side of the cows while using the other empty side as a negative control. The administration frequency for MR was of 2 days/week/1st-month, then 2 days/2 weeks/2nd-month, and then 2 days/month, and for IR was of 2 days/week/1st-2nd months, and then 2 days/2 weeks. Footbaths were administered during 140 days (approx.), and feet were evaluated for the at least once a month in the milking parlor. Nested survival models were used to estimate the relative impact of the footbath regimens and other concomitant risk factors on the time that bDD lesions occurred or healed. No effect of Pink-Step™ was evidenced on the bDD occurrence during the trial. The risk for bDD occurrence was increased by poor feet cleanliness at both the cow (HR 1.69, CI 1.21–2.39) and farm level (HR 2.06, CI 1.44–2.94). Otherwise, the use of Pink-Step™ in an IR was effective in improving the healing of bDD lesions (HR 1.79, CI 1.12–2.88). The time to healing was also improved in inactive lesions (HR 2.19, CI 1.42–3.37). Conversely, the time to healing was delayed in feet receiving hoof-trimming (HR 0.41, CI 0.26–0.62), in cows with a contralateral bDD lesion (HR 0.32, CI 0.22–0.46) or in late lactation (HR 0.61, CI 0.43–0.85), and finally in farms with more than 100 cows (HR 0.48, CI 0.34–0.67). These findings reinforce the crucial role of hygiene in bDD dynamics and highlight the importance of implementing multiple control measures simultaneously, such as hygiene improvements in the barn, early detection and treatment of bDD lesions and the correct usage of individual and collective treatments. The implementation of Pink-Step™ represents a promising strategy for reducing the persistence of bDD lesions in affected herds.