I have 2 yearling heifers that I bought from a neighbor ( out of my cows and bulls) mixed in with a group of 20 other yearlings. The 2 I bought are loud breathers. You can here them from 30 yards away sometimes. They are not laboring to breath, just noisy. No nasal discharge whatsoever. Other than the breathing they are perfectly normal. They come from a closed herd, so I'm hoping it is not IBR. But I have had trouble with it in the past, although not in a few years. Everything I raise gets vaccinated at 3-4 months, then again at weaning. The 2 with the problem didn't get any kind of shots till weaning. Should I be worried? Or can I turn them out with the others and forget about it?