Not all the Steynmere lines carry bobtail genes. I have two bitches both from Steynmere lines that aren't bobtails.
But Steynmere is the creator of the bobtail so when doing pedigree analysis you would expect to find a Steynmere bobtail
in the pedigree. Although there are some 'quirks' of nature and you will have the odd dog crop up with a bobtail.
Dr Cattanach had a Norwegian dog in the UK for a time with a short tail which was called Cavajes Beyond Belief (Mack).
He wasn't a dog that was intentionally bred for a bobtail. Infact I think if I remember correctly there were no bobtail
lines behind him. So it can and does happen but I think it would only be the odd dog in a litter not all

Dr Cattanach has bred bobtail to bobtail to see the effects. I think you would have to ask him for further answers.
(He is rather busy at the moment with Cardiomyopathy work for the Boxer Health Committee).
I had a litter last year, of the 7 pups I had 2 that were bobs and both had slightly different lengths of tail.
I know of another litter using the same sire that had pups and she had 4 of 6 pups with bobs.
I also heard that another lady had a daughter of this sire that had 6 pups and 5 were bobtails.
So as you can see from the above it does vary. I wouldn't ever think that there would be a possibility of a whole litter
being bobs, but as above I have heard from others who have come close to all the litter being bobs (always typical
isn't it when you would like a bit of a choice it never happens..still I'm happy with my Nora)
My bobtail was at Crufts doing Discover Dogs on the Friday this year along with her tailed litter sister and their 2nd cousin (docked).
If anyone wants to see her, she is being campaigned in the Southern Counties regions at Open shows and some Champ Shows.
(I have my vets letter to prove she isn't docked)
Her temperament is typical Boxer, and although she isn't a flashy Boxer, she's classed a solid (like her sire) as she has minimal white markings.
If anyone is at Southern Counties on Working day you can see her there too. She's NFC there but her longtailed flashy sister
will be competing in classes and again they are typical 8 month old Boxer pups.
My two girls are 6th generation bobtail bred.