How different is it raising bison versus raising cattle?
Well first off, raising cattle ranchers need procedures like checking for calves in the winter, pulling out calves which cows are having trouble birthing, and worrying about food, water, and if their animals will survive a storm. Raising bison involves none of the above, so it's easier and much less stressful.
Bison can of course, be raised in small pastures and fed year round or raise them and perhaps only supplement feed in the winter.
Bison can be raised without being fed manually. Prior determination from your local Department of Agriculture will define how many acres are needed per animal unit (1 bison is 1 animal unit).
Other factors are if the land is dry or irrigated, etc.
Bison drink about 10 -12 gallons of water per day (more in the summer). They can feed on snow for a while; and will jump on icy water tanks to break the ice for water. Also, when they are thirsty - they will search for water.
Bison are herbivores.