Comparative efficacy of stannous fluoride and zinc sulfate solution to copper sulfate footbath solutions for the treatment and prevention of digital dermatitis in lactating dairy cows.

The objective of this study was to determine whether a novel footbath solution containing stannous fluoride (SnF) was superior to 5% copper sulfate solution for the treatment and prevention of digital dermatitis (DD) in dairy cattle. Study 1 was conducted over 4 wk in Missouri and involved 34 lactating Holstein-Friesian cows with hind feet DD lesions. Cows in group SF walked through a footbath containing a proprietary formulation of SnF once weekly, whereas cows in group CS walked through a 5% CuSO footbath once daily for 5 d each week. Study 2 was conducted over 8 wk in California and involved 40 lactating Holstein-Friesian cows with hind feet DD lesions. Cows in group SF walked through a SnF footbath for 3 consecutive days and then once a week for the following 7 wk. Cows in group CS walked through a 5% CuSO footbath 3 times each week for 8 wk. Data collection included lesion type, lesion area, locomotion score, and pain score. Digital dermatitis was actively transmitted in study 1, and lesion area and locomotion scores were lower in group SF than group CS. In contrast, DD was not actively transmitted in study 2, and lesion area and locomotion scores were similar in groups SF and CS. Stannous fluoride delayed the development of active DD lesions in study 1 compared with copper sulfate, with a lower relative risk (0.57) of a hind foot developing an active DD lesion over 28 d. However, SnF decreased the rate that active DD lesions transitioned to M3, M4, or M0 lesions compared with 5% copper sulfate in both studies, with the relative risk of a hind foot with an active DD lesion transitioning to M3, M4, or M0 in group SF being slightly lower in study 1 (0.83) and study 2 (0.90) than in group CS. Our findings demonstrated that walking cows through a stannous fluoride footbath once per week in a herd undergoing active transmission of infection was more effective in preventing active DD lesions, but less effective in treating active DD lesions, than walking cows through a copper sulfate footbath 4 times per week. The novel SnF footbath solution shows promise for controlling DD in dairy herds that want an alternative footbath solution to CuSO and are interested in limiting the environmental accumulation of copper.