ORIGINAL: nchawkeye

Cast...Don't know where you are located, but I do similiar as IL...
I use 2 to 1 from Southern States...It has calcium, phosphate and salt...
Its called 2 to 1 because it has 14% phosphate and 7% calcium (or the other way around, I can't remember)...The salt content is 20-25% as is...

Funny thing, some farms I hunt the deer will hit it as is...On some I add
loose, bulk salt to help them hit it....

Most feed stores carry some type of these supplements, the contents vary
because some are made for beef cows, some for calving cows, some for
dairy cows, etc....