I am going to agree with tornado. We have had experience with ringworm and warts. Warts tend to be "bumps" that stick out and ringworm looks just like what is on this calf. The way we treated it was to use a wirebrush just hard enough to break through the crusty layer and to make it appear raw. Then use iodine on each individual place. You can use a cloth, cotton, gauze or whatever to put the iodine on. Another thing that we found to work really, was a type of spray that is used on apple trees. Unfortunately, I forget the name of it but my DH may remember it. It is not life threatening to the calf and will eventually clear up. It is more in the looks of the calf. Hope this is helpful info.