I would think there would have to be some Canadian cattle of dual purpose descent that would be "native" in Canada. There are several dual purpose herds in the states that I think would be "native."
I have always been interested in why people want to preserve these genetics, other than for just the sake of preserving the genetics. That is a good reason, but are there others? My experience has been that a blend of the old with the new is pretty good. On the other hand, if the old genetics, or the new for that matter, aren't what you want, the resulting mix won't be good, either. Perhaps the best breeding bull I've bred and used combines the breeding of Leader 9th, Deerpark Leader 18th, and Cates' Nobody's Fool cow. He's extremely pleasing to the eye and I use him with utmost confidence on heifers. I have always found it kind of fun to try to combine the genetics available and come up with a success once in a while.
Dad always raved about Golden Bantam sweet corn, It is not readily available through the seed dealers, but I found some on e-bay, believe it or not. It was just as Dad said it was 50 years ago. Very large kernels, 8 rows per ear, very chewy and flavorful. It was a single cross, so any seeds planted would reproduce themselves. I know there is a group out there that attempts to preserve various crops and breeds of livestock. For many, many years we planted DeKalb XL-45 and Pioneer 3780 corn. They were the best we could get back then, but would not compare with the varieties of today.