The first thing we do is to try to prevent them, which is probably a cliché answer, but we do everything we can to avoid them.
For example, right now at our home farm we have 300 stocker cattle, and we practise what's called intensive grazing. The animals are moved every two or three days, depending on the size of the fields. That helps us avoid having to use any kind of dewormers; the parasite pressure is diminished by constantly moving the cattle into new pastures. That's an example of a step we would take to try to ensure we don't have to.
Inevitably there will be animals that get sick, one way or the other. If we have to treat them, they're segregated from the program, they have to be tagged differently and kept separate. What we generally do is, if we think they're getting sick or we're going to have to treat them, we ship them off to a stockyard and sell them on the commodity market.