We do the same as Bama. The ones from the salebarn get hit with LA200. Easier to get first signs of something earlier rather than try to treat later. LA200 isn't expensive either. The dry cough could be something simple like change in feed, dust, environment, etc. That sort of thing will run its course and get worked out. LA200 won't help but won't hurt either. Good first step though if it turns out to be something more. We tend to treat calves sooner as calves can go down so quick. It also eliminates the self blame if things go wrong. You can't say I shoulda done something.... cause you did do something.