Digital dermatitis (Mortellaro's disease) is the most common infectious cause of lameness in dairy cattle worldwide, causing painful foot lesions that significantly impair welfare and mobility.
Digital dermatitis causes intense pain that profoundly affects the daily experience of affected dairy cows. The M2 lesion stage — an active, ulcerated lesion typically 2-10 cm in diameter — is acutely painful on contact and causes significant gait alteration as cows attempt to avoid bearing weight on the affected foot. The welfare impact extends beyond the foot: cows with lameness lie down more (when pain allows) but also reduce walking to feed and water, compromising nutrition and hydration. Research using grimace scales and pressure mats confirms that DD causes pain comparable to other major lameness conditions. Because DD is highly contagious and spreads rapidly through contaminated slurry, whole-herd approaches to control are necessary. Farms with effective DD control programmes achieve dramatically lower lameness prevalence, representing one of the most impactful welfare improvements available to dairy producers.