I would not assume what the dog has, or that there is no other treatment than a disc buggy - or even that a disc buggy is appropriate.  It isn't always.  If the prednisone is helping then that's the ticket.  
I wouldn't assume any natural treatment would help a degenerative disc/neurological problem long term - it usually has nothing more than a temporary placebo effect.  The condition marches on as time passes.
Many doxies  do develop back and related neurological and pain problems.  
Years ago, doxies were longer on the leg, shorter of back, and had sounder front and rear legs.  They actually were very hearty hunting dogs and quite durable.  It's going to extremes in type that has made the back problems so common.   A breed I loved as a young person, and now avoid, which is sad.