Digital Dermatitis is an infectious condition of the foot caused by bacteria called Trepanomes. The first early lesion looks like a raw sore at the back of the foot (usually the rear feet) between the heels. At this stage the sore is painful and the cow or heifer when standing, does not want to put the foot down firmly. She may not be too lame walking as it is more obvious when standing still. With time the dermatitis lesion hardens up and is less painful, but the cow remains a carrier for some time and so a source of infection to other cows.
At this stage, at least 5 cases of Digital Dermatitis infection have been found in New Zealand herds, with at most only a few cows in each herd affected. In Australia the situation has been like NZ, but now it appears to have moved into the next phase and some herds have multiple cases. The bacteria like dirty conditions on the skin of cows feet, so the increased use of housing, feed-pads and dirty entrances and exits could be risk factors in the future that could see this disease establish itself here if we don't take some preventative measures.
Keep a look out for lame cows with a lesion like those in the photos. If you identify any suspicious cases, separate the cow and get call the clinic. We can come out and take a biopsy and work out a plan of action.