Effects of different intervention strategies on the incidence of papillomatous digital dermatitis in dairy cows.

The effects of four different intervention strategies on the incidence of severe lesions of digital dermatitis in an experimental dairy herd were compared with the effects of a control strategy consisting of walking the cows twice through a footbath containing 4 per cent formaldehyde on one day a week for 24 weeks. The four alternative strategies were the same treatment every other week; standing for 30 minutes in a footbath containing a 2 per cent multicompound solution on days 0, 7, 28 and 90 after having had their hooves cleaned indirectly with a medium pressure spray of water; walking twice through the multicompound solution on one day a week for 24 weeks; and, walking twice through a footbath containing 3 per cent sodium carbonate on one day a week for 24 weeks. The cows' hooves were inspected every three weeks by one trained claw trimmer who graded the lesions of digital dermatitis. None of the alternative strategies significantly reduced either the number or severity of the lesions in comparison with the control strategy. In the groups treated by the third and fourth strategies there were outbreaks of digital dermatitis in which more than 30 per cent of the cows suffered the most severe type of lesion, and there was a continuously high rate of new infections in the group treated by the fourth strategy.