Daily forage intake of beef cattle on grazing lands can be variable depending on management, animal, and ecological factors, and is difficult to estimate. The animal unit (AU) concept is based on forage intake and is used to balance forage supply and demand on grazing lands. Forage demand is commonly reported as stocking rate (AU days of forage per ha; AUD/ha) and is calculated based on a ruminant consuming daily a certain percentage of its liveweight. There is disagreement among advisors and practitioners alike on the daily intake (AUD) of a grazing ruminant. The standard intake amount used by University Extension and federal agencies, such as the Natural Resources Conservation Service, ranges from 2.3% to 2.7% of liveweight (10 to 12 kg dry matter for a 450 kg animal). A stocking rate based on the 2.7% intake is lower than that of a 2.3% intake and likely results in reduced harvest efficiency and beef production; therefore, identifying and using accurate estimates of intake are critical. Research was conducted from 2013 through 2016 on a subirrigated meadow at the University of Nebraska-Lincoln Barta Brothers Ranch in the eastern Sandhills. Steers were rotated through pastures of two different grazing systems during the growing season. Immediately before and after the steers were moved to a new pasture, sample locations within the pastures were clipped at ground level, the clipped vegetation dried and weighed, and disappearance (intake) calculated. The difference in standing live vegetation biomass between the before and after clipping was considered intake. For the two grazing systems and 4 years of the study, estimates of forage intake were better predicted by the 2.3% of liveweight factor than the 2.7% of liveweight factor. These results confirm that the AUD equivalent of 10 kg DM/AUD is accurate.
Oral presentation and poster titles, abstracts, and authors from the Society for Range Management (SRM) Annual Meetings and Tradeshows, from 2013 forward.