Alan":3jk4r7j7 said:
Hope this isn't too big, but you may be able to see how thin the hair is, top of the tail is completly bald.
Alan,
If you are using a registered Herefords, I would have it or it's parents DNA checked for hypotrichosis. AHA has already identified some animals, and specifically some Hereford bulls to be carriers of this defect. The American Hereford Assoc. has a list of the bulls which are carriers. Perhaps one of the bulls is in your lines.
If you don't run registered stock and can't track the bloodlines then I would watch the offspring of that cow or bull closely to see if this passes some more.
The calf also appears to have a light rash under the skin too, so it could be something completely different and you should check with your vet. Was it by chance washed down with some fuel oil or gasoline?