Invited Review: Growth, voluntary intake, and digestion and metabolism of North American bison

Purpose: Published literature on growth, voluntary intake, and nutrient digestion and metabolism of North American bison (Bison bison) was reviewed to create an information base for implementing management strategies. Sources: The information came from refereed scientific journals, published textbooks, experiment station reports, and PhD dissertations. Synthesis: After narrowly avoiding extinction in the 1880s, about 400,000 North American bison are in the United States and Canada today. Voluntary intake and growth are depressed during the winter and rebound during the following spring and summer. Domestic cattle and bison share similar grazing behavior, intake capacity, and ruminal fermentation characteristics. Greater DM digestion coefficients for bison compared with cattle appear to result from less DMI for bison than cattle in the studies. With the exceptions of red blood cell quantity and characteristics, and greater glucose and BUN concentrations, bison and cattle have similar blood histology profiles, enzyme activities, and mineral and metabolite concentrations. Conclusions and Applications: Available forage biomass and nutritive value, not capacity to eat, will limit acquisition of needed nutrition by grazing bison. Management of domestic herds should take into consideration the annual "winter slump" in intake and growth. Any putative advantage in fiber fermentation capacity in bison compared with cattle does not appear to be due to differences in ruminal microbial populations. In feedlots, bison consumed feed DM equal to about 2.5% of BW, gained 750 g/d, and converted feed to gain at 9% efficiency.