Tebuthhuon, [N-(~l,l~hy~yi-ll~,~~oi-~yi~N~dimethylureaj, a root-absorbed peiieted herbicide, was broadcast onto sand shinnery oak (Quercus havardii) rangeiand in west Texas, May 1978. Green berbrge of the dominant grasses was assayed for nitrogen (N), phosphorus(P), 24hr in vitro dry matter digestibility (24 hr-IVDMD), and ceil waii content (CWC) on 3 dates in both 1978 and 1979. ln 1978, tebuthiuron at 0.4 kg/ha or above improved quality of the major forages. Crude protein was up to 28% higher in treated plants the year of application. The P content ranged from 0.08 to 0.12% over all sampling dates. Digestibiiity increased slightly while no difference was found in CWC. Tebuthiuron had no effect on forage quaiity the year after application. The most consistent change in parameters measured was water content of little bluestem (Schikachyrium scaparium). Untreated plants averaged 38% water throughout the growing season, while treated piants contained 50% water. Major benefits of killing oak are increased forage availability and not yet resolved palatability factors. Over 2 million ha of sandy soils in the Southern Great Plains support sand shinnery oak (Quercus havardii). This dwarf oak provides some food and cover for livestockand wildlife, but its new growth is toxic to domestic stock. Nearly 80% of the standing crop is oak. Conversion of this shrub type to a mid-grass prairie is a goal of many ranchers. In December, 1979, tebuthiuron was registered for use on this species. Pettit (1979) found that some oak may be controlled with tebuthiuron at rates as low as 0.24 kg/ha. Concomitant to increased production, forage quality may be improved with herbicides (Bovey et al. 1972, Scifres et al. 1977). Cattle seem to prefer grazing forages treated with tebuthiuron. This preference may be related to forage quality. Arnold (1964) found grazing animals to prefer forages high in nitrogen (N), phosphorus (P), and sugar, but low in fiber. Leigh (1961) stated that forage water content was highly correlated to preference. Herbicidal effects on the nutritive content of rangeland forages are not fully understood. The study by Houston and Van Sluijs (1975) is not directly applicable to our area because of soil fertility and environmental differences. Sosebee (1979) used high rates of tebuthiuron (9 kg/ ha) and found that forage protein, P, and carotene were not affected, but forage water content was increased. The impacts of herbicides on digestibility and cell wall content (CWC) of forages after herbicide treatment have not been reported for