Beefalo are 3/8ths bison and 5/8ths cattle. so no, bison/cattle hybrids are NOT infertile. The reason most breed bison bull to cows, rather than a bull to a female bison, is purely economic. Bison females are a LOT more expensive than cows. And, it takes a lot higher, heavier and sturdier facilities for bison. 6' high fences at a minimum. a lot cheaper to keep 1 bison bull than a herd of bison females. A lot easier to work the claves, etc, with cows vs bison, too. You'd make a lot more money, if you did have a herd of bison cows, to breed them to a bison rather than a bull. The only people I ever knew in Ga that raised bison were two different cutting horse trainers. 1 bison can wear out 2-3 horses in training where as it would take 5-8 steers or heifers, to work one horse out good. Especially when you are training one for Reined Cowhorse. If you have a horse than can first....catch a bison... and then stop it and turn it...then it can catch, stop, and turn any cow in any competition.