This research was conducted on three study areas on elk winter ranges in Northeast Oregon. One was on the Starkey Experimental Forest and Range and the others were in the same vicinity. Plant appendages, spring and fall defoliation and fall growth of bluebunch wheatgrass were evaluated in terms of quality of nutrient content during September through April of 1986-87 and 1987-88. Four treatments were applied. Plants were clipped to a 2.5 cm and 7.6 cm stubble height in the spring before the boot stage of phenological development; plants were clipped to a 7.6 cm stubble height in the fall after plant maturity in September; plants were not clipped during the year. Percent crude protein, dry matter digestibility (DMD), acid detergent fiber (ADF), and lignin were evaluated monthly. Samples from the four treatments were also analyzed from October to April to determine monthly changes in nutrient contents. Production of growth from all treatments was measured in October and March each year. Leaf material had higher percent crude protein and DMD, with lower percent ADF and lignin than the inflorescence and culm. The third leaf (the youngest plant material) had the highest nutrient value of all appendages. The culm and inflorescence values were not statistically different. Growth following spring defoliation treatments produced higher percent crude protein and DMD (P<.05), with a lower percent ADF and lignin than non-treated plants in both years. This was particularly pronounced during 1986 when precipitation in late summer initiated fall growth. Growth following spring defoliation and bluebunch wheatgrass not defoliated did not produce crude protein or DMD values sufficient to meet minimum dietary maintenance requirements for elk. Fall precipitation adequate to promote fall growth occurred only in 1986. Growth after fall defoliation had the highest percent crude protein and DMD with the lowest ADF and lignin values of all vegetation sampled. However, without 3-5 cm of late summer/early fall rains, fall growth does not occur. This happened in 1987. When growth does occur in fall the quality of the growth exceeds the minimum dietary maintenance requirements for elk. Freezing and thawing of fall growth plant material had minimal effect on forage quality. There were differences (P<.05) between the monthly values for percent crude protein and ADF starting in October and ending in April. However, the percent DMD and lignin from October to April were not different (P<.05). / Graduation date: 1993