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One objective of the Renewal on Standing Rock Reservation project is to evaluate grazing steer response to level of prairie dog (PD) colonization on Northern Mixed Prairie. Four pastures (200 ± 10 ha) were fenced to create an increasing gradient of proportion of the pasture area occupied by PD colonies (0, 18, 40, and 75%). Pastures are stocked with yearling steers to create equal grazing pressure in each pasture by reducing stocking rate in proportion to increasing PD colonization. Steers are weighed at initiation, mid-point, and end of each summer grazing season. Proportion of steer time spent on- or off-PD colony is being determined by placing GPS collars on 5 steers in each pasture. Two GPS collars in each pasture have activity switches to determine amount of time spent grazing on- or off-colony. Ruminally cannulated steers are used to collect diet samples for nutrient analysis in temporary enclosures in 3 locations: annual-plant-species dominated core of PD colonies, grass-dominated portion of PD colonies, and off-PD colony. Ingestion rate is calculated as the weight of forage collected during diet sampling divided by grazing time during sampling periods. Ingestion rate in each sampling location multiplied by grazing time per day in that location is used to calculate daily forage intake from PD colonies vs. off-colony. Forage intake is multiplied by nutrient content to calculate effect of grazing location on nutrient consumption. Comparing these at each proportion of PD colony per pasture allows prediction of the optimum proportion of PD colony to allow cattle to select the most balanced diet to meet performance goals. Additionally, it will allow recommendation of management options for any given level of PD colonization to optimize cattle nutrient intake. Extension programming will utilize this information to assist Native American ranchers to optimize land resource utilization in beef enterprises.