They tend to give antiB's to err on the side of caution just in case the dog picks up a secondary infection in the lungs (like a person starting with a cold and getting a chest infection).
Must admit mine have had cough twice now - 2years ago the then four I owned caught it, I used Ecchinacea, devil's claw, honey and warm water 2-3 times a day, kept them warm in the house. Earlier this year one of the youngsters got it (under 2 years of age) and the other young bitch caught it, sods law I had 4 week old pups, I treated them all in the same way though the pups never caught it and neither di