Well, I think that's partially true. There are two parts to your question, the somatic cell count or the cell count in the milk could come from.... Infection can come from other things. It comes from trauma, bad milking machines, and a number of different indicators. Of course, in the dairy industry they look at that because when it gets too high, that milk is no longer processed into cheese and whatnot, so it is rejected. There is a gradient of what your cell count can be before suddenly you're starting to lose your milk stream.
That is a good example of where you can monitor what's going on. That's not always involving antimicrobial use, but if you have mastitis in a dairy herd then you have a higher incidence of wanting to use dry cow treatment, which increases the use in the herd.
There are ways you can reduce that need for antibiotics through management techniques, for sure.