We have a 6 week old black angus calf that we are feeding maxi calf from a bucket because his mother had to be put down from a broken hip. He received the first milk and nursed her for 4 days before we started him on the bucket. He now sucks down 2 quarts of maxi calf milk mix in about 60 seconds from a regular bucket. We vaccinated and banded him Friday, November 21, and now he has several patches on his neck and face that he has lost his hair. He doesn't seem to be itchy, but the patches are getting bigger. Skin under the patches is smooth and looks healthy. We put a block of trace minerals salt in the pasture with him Sunday, and he licks on that some. Any ideas on what could be wrong with him?