Calves are stout, bouncing around -- but 75 degree days and 35 degree nights worry me.  I'm working them this weekend (tag and 1st shots) -- should I give them some meds as precautionary or wait until I see something?

I had one that died on me earlier in week, don't understand it.  Strong healthy heifer calf, no scours....but the weather can't make up it's mind.