A friend of mine had a calf last year that acted like yours. He hung plastic bags (Wal-Mart, Kroger, Etc.), all around the steers pen & stall area. This solved his problem.
We have had good luck with Dr. Naylor's Blu Kote ( aerosol ), usually takes two to three treatments. We order it from Jeffers Livestock ( Equine Section ). Once you have killed it use MTG to help grow hair back.
Go to Sullivan's web site and scoll down to the bottom, on the left hand side click on daiy hair care. It will tell you what they recommend. Hope this helps.
What are some of the things you have done to hold a steer? I have a steer that wieghs 1100 lbs he needs to way around 1300 lbs at the end of March. We are feeding him 6 lbs of cottonseed hulls with 2 lbs of beet pulp twice a day, and he is still gaining weight.