I'm glad it works, although I think it would be more risky to change the Sheepdog's ID number. Everybody has the base game breeds, and they're typically the same ID numbers, and if you change your Sheepdog's ID number and adopt out a pet to somebody else, it might cause problems in the other game. Or, your old Sheepdog mixies who used the other ID number might have issues. I don't recall if they simply don't work, or if it badly effects their breeding, but it causes a handful of problems and it's actually a lot messier.
What I would do is use LNZPro and do this...
Open LNZPro, and use the dropdown list at the top, and click Open Folder:
Then navigate to where your game is located, and to your Dogz folder.
Once there, on the right-hand side click the Breeds And Toys tab near the top. Find the Sheepdog, click it to highlight it, then sort them all by ID number. Any files using the same ID number as the Sheepdog should be right beside it, and you can then open them later and change their IDs.
And personally, I'd make sure there's no Catz clashing too, but that might not be required. I've had a problem in the past where I was breeding from a breedfile which shared an ID number with the opposite species and my GOSH did it ever bug out the babies.
So I had to make sure (using this technique I just showed) that NONE of my ID numbers were identical, between Dogz AND Catz, and I have to check any new ones before I use them.
Overlapping ID numbers make a MESS of Petz, especially when the original breeds get messed with. xD Anyway sorry for the book, do what you want, but this would be better than changing the Sheepdog's ID number. ^^