Hi Jannie,
I really have no personal information that I can offer, but I checked the web and found this article...I think I'd get another opinion...or at least request that the vet continue to look for the cause. Often when tests come back negative, the vet quits looking and it is up to us to prod them a bit.
http://www.canismajor.com/dog/cough.html
I hope that Sadie gets better soon...I was surprised to see in this article that you can give them children's cough medicine. Maybe that will help a bit.
I really have no personal information that I can offer, but I checked the web and found this article...I think I'd get another opinion...or at least request that the vet continue to look for the cause. Often when tests come back negative, the vet quits looking and it is up to us to prod them a bit.
http://www.canismajor.com/dog/cough.html
I hope that Sadie gets better soon...I was surprised to see in this article that you can give them children's cough medicine. Maybe that will help a bit.