The relationship between biosecurity and herd prevalence of digital dermatitis (DD) was evaluated in 8,269 cows in 39 Danish freestall dairy herds. All lactating cows were scored as negative or positive for DD on their rear hooves during milking in the milking parlour. Within-herd DD prevalence ranged from 0 to 56%.
Poor external biosecurity practices associated with higher DD prevalence included recent animal purchase, access to pasture, heifers raised in multiple herds, lack of boots available for visitors, farm staff working at multiple dairy farms, and animal transporters having access to the cattle area.
For internal biosecurity, higher DD prevalence was associated with infrequent hoof bathing, manure scraping less than 8 times a day, manure removal direction from cows to heifers, manure-handling vehicle used in other activities, and water troughs contaminated with manure. These findings demonstrate that improvements in biosecurity may be beneficial for controlling DD in dairy herds.
source: Victor H. S. Oliveira, Journal of Dairy Science 100:8398 (2017) (full article is here)