[Help] New dog terrified of cats.

I recently adopted an 8 year old Aussie (who has lived with a cat previously) We're having some issues with him and my Mom's 2 year old cats, he is absolutely terrified of them, and now I think the cats have caught on to this and torment him on purpose. (running up to him and puffing up)The cats have grown up with dogs, and although they were a bit scared of the new dog, they seem to have gotten over that pretty quick. I've been keeping them separated when I'm over on weekends, but help? via /r/dogs http://ift.tt/2rP3z2o