What comes out? I mean behaviorally and physically? If you breed an American and European bison.
American
http://cwf-fcf.org/assets/images/bis...-Hill-1680.jpg
European
https://upload.wikimedia.org/wikiped...aeus_1758).jpg

The American bison is much more bold, used to the open plains and much larger and aggressive and can run in gigantic herds, while the European bison live in herds with around ten animals, are more shy and tend to inhabit forests and mountain regions.