When we first got our border collie we already had another dog (mongrel) who never really got along but ended up tolerating each other. When we had these two we got lab pups and while the collie got along extremely well and the other dog was the same as when we got the collie with the labs but grew to tolerate them again. The labs eventually had to leave due to relocating and their not being enough room for them though we still see them every once in a while so its not too bad for them (worst mistake of my life, miss them to this day and believe dogs should have homes permanently which is why im asking this question). This was around 8 years ago now and the collie is turning 15 but is in great health except her hips have been going for a while so she cant go on long walks to socialise with other dogs and its been this way for a couple of years. Now I would like a male Doberman and was wondering how people think they would both get along with each taking into account the lack of socialisation and age of the collie. Also worth nothing when she does meet other dogs in the short walks she can now manage she does get on well with them and she has a generally exceptional temperament and behaviour. I hoping in might perk her up in her old age and she may mother it a little bit once they get to know each other. Any questions ask me and thanks for all input.