Countrygal,
Now correct me if I am wrong.
You are having a lameness problem with a bull in multiple legs over a period of time, correct? But you are not having the same problem with the rest of your animals, correct?
To me it sounds like you are dealing with a white tissue joint (s) problem, not an injury which could be caused by a copper/selenium deficiency.
The lameness condition often shows up in a bull first, vs. the cows, due to his weight and physical/mounting activities.
Here are two sites that can explain it better then I.
Vigortone's Tec Bulletin 06-5
http://www.vigortone.com/tech_library/t ... oncept.pdf
Note: ( Table 1. ) a copper deficiency can cause lameness and a selenium deficiency can cause white muscle disease, which is what I am reading in your posts.
If you are not already feeding, free choice, an inexpensive mineral block, I would recommend it.
If you already are feeding minerals, see "Table 2" and note: Sulfur ties up both copper and selenium and is an antagonistic to both copper and selenium .
For additional help see Vigortone's Tec Bulletin 06-44 Last paragraph.
http://www.vigortone.com/tech_library/t ... y%20Su.pdf
Hope this helps