The historical evidence clearly shows that pemmican was made with a large number of different animals. Moose, caribou, deer, wood land buffalo, bear, as well as fish, to name but a few, were all used to make this important food.
Buffalo was used in the southern regions by the Indigenous populations and later by Europeans because of the sheer ease of accessing this important resource. At one time, millions of buffalo roamed the plains.
By the mid to later part of the 1800's the vast majority of plains buffalo were wiped out as a result of the pemmican, robe and leather trade. It was at this time that beef was starting to be used as the primary ingredient for pemmican and leather production.
Now, in the 21st Century .... if I were to use buffalo meat and buffalo tallow, as the main ingredients for my product, it would be much too expensive for people and schools to afford.
Maybe in time, dependent upon future buffalo product prices, I may introduce a new line of pemmican buffalo products.