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Anticipation of changing conditions and the identification of sources of vulnerability is critical to selecting effective adaptation measures. Rangeland changes are not expected to be uniform, thus appropriate actions will not be universal. We examined the vulnerability of cattle production on U.S. rangelands to climate change effects by estimating changes in forage quantity, vegetation type trajectory, heat stress, and forage variability. Our measure of vulnerability assumed livestock operations were sustainable under climate conditions of recent experience, thereby providing a locally derived estimate of change. Projections to 2100 were translated into vulnerability as departure from the current baseline (2001-2010). Forage quantity was taken from a biogeochemical cycling model of net primary productivity (NPP) and was projected to increase in northerly regions potentially benefiting cattle production. The trajectory of vegetation type towards or away from preferred cattle forage was estimated using the dynamic vegetation model, MC2. Vegetation types were projected to move towards more grass types overall, but there was considerable heterogeneity across the rangeland extent and within regions. Heat stress was estimated as the number of days per year where the thermal neutral zone for beef cattle would be exceeded. Projected impacts were consistently negative across multiple elements in southerly and western rangeland regions providing strong evidence for declining production. In northern and interior regions, benefits of increased NPP or inertia towards grassier vegetation types were mostly tempered by negative impacts from increasing heat stress and forage variability. Southwestern rangelands and cattle operations experienced the greatest problems but disagreement among elements as to the direction of change indicates that reliance on projections for a single element will limit our ability to anticipate impacts and sustain livestock production obviating the need for integrated impact studies such as the current work.