My goats have had a chronic cough all summer and on and off snotty noses. If I make them run it sounds terrible with all the coughing. They were wormed with Valbazen in July. I've checked the worst one and the temp was fine so it doesn't seem to be any type of infection. We've been in an extreme drought and everything was dusty but lately it has rained enough to wash the dust off the plants so I don't think it's dust. The goats got only browse until just recently. Any suggestions?