This helps, but doesn't solve the problem entirely. We have some data showing cattle with antibiotic resistant E. coli to antibiotics that are not administered

This helps, but doesn't solve the problem entirely. We have some data showing cattle with antibiotic resistant E. coli to antibiotics that are not administered to livestock, because they're carried on the same plasmids as other resistance genes that confer a fitness advantage in some other way (i.e. another antibiotic, heavy metals, etc.) That's not to say that regulating its use isn't a good idea, just that it's really complicated.