Abstract: Decline of wild prey populations in the Himalayan region, largely due to competition with livestock, has been identified as one of the main threats to the snow leopard Uncia uncia. Studies show that bharal Pseudois nayaur diet is dominated by graminoids during summer, but the proportion of graminoids declines in winter. We explore the causes for the decline of graminoids from bharal winter diet and resulting implications for bharal conservation. We test the predictions generated by two alternative hypotheses, (H1) low graminoid availability caused by livestock grazing during winter causes bharal to include browse in their diet, and, (H2) bharal include browse, with relatively higher nutrition, to compensate for the poor quality of graminoids during winter. Graminoid availability was highest in areas without livestock grazing, followed by areas with moderate and intense livestock grazing. Graminoid quality in winter was relatively lower than that of browse, but the difference was not statistically significant. Bharal diet was dominated by graminoids in areas with highest graminoid availability. Graminoid contribution to bharal diet declined monotonically with a decline in graminoid availability. Bharal young to female ratio was three times higher in areas with high graminoid availability than areas with low graminoid availability. No starvation-related adult mortalities were observed in any of the areas. Composition of bharal winter diet was governed predominantly by the availability of graminoids in the rangelands. Since livestock grazing reduces graminoid availability, creation of livestock free areas is necessary for conservation of grazing species such as the bharal and its predators such as the endangered snow leopard in the Trans-Himalaya.