POTENTIAL FOR WOODY PLANT CONTROL BY SPANISH GOATS IN THE SAGEBRUSH STEPPE

The botanical composition of the diet of eight Spanish goats was studi ed on the Northern Great Basin Experimental Range during two stages of plant phenology (active growth in early July and cured forage in mid- August) to assess their potential for control of sagebrush (Artemisia tridentata subspp. wyomingensis Nutt.) and western juniper (Juniperus occidentalis Hook.) and the nutritional value of their diets on sagebr ush steppe rangelands. Diets were quantified by documenting the number of visits to each species, the number of bites harvested and time exp ended grazing each forage over four consecutive days in each period, F orage chemical characteristics evaluated included: CP, NDF, ADF, ADL a nd IVDMD. Diet composition and forage quality indices varied significa ntly (P<0.05) with changes in plant phenology. Vegetation cover averag ed 52% in the pasture and consisted of 36% grasses, 8% forbs, 7% shrub s and 0.6% trees. Available herbage (excluding woody plants) was 534 k g ha(-1) during active growth trials and 572 kg ha(-1) when forages ha d cured. When Forages were green goats acquired 28% of their total bit es from grasses, 71% from forbs, 0.3% from shrubs and 0.9% from junipe r trees. After forages had cured values were 35% from grasses, 56% fro m forbs, 0.1% from shrubs and 8.8% from juniper. The browsing of junip er (both foliage and bark), alter herbaceous forages had cured, was th e only substantive use of woody plants. Sagebrush was only lightly use d (0.2% of total bites) when herbaceous forages were actively growing. Available herbage was of relatively high quality during both trials. When forages were actively growing, CP of grasses ranged between 8.9-5 .6%, forbs from 17.7-8.5%, sagebrush scored at 8.5%, juniper foliage a t 8.1% and juniper bark at 3.2%. After herbaceous forages had cured, g rass CPs ranged between 6.2 and 3.1%; forbs from 10.4 to 4.4%; shrubs were not sampled; and juniper foliage averaged 7.6%. Given the low lev els of browsing exhibited by goats on sagebrush and juniper we see lit tle opportunity for control of these woody plants when pastures provid e a diverse (n = 25 species) array of readily available (534-572 kg ha (-1)) and nutritious forages and pastures are lightly stocked (0.63 go ats ha(-1) month(-1)). We do need, however, to explore further their p otential for control of these species under several other regimes. The se include: extended trials on more deteriorated rangelands; trials du ring seasons or conditions where forage is limited and the animal's se lective opportunity is restricted; and trials in high quality environm ents on newly established sagebrush and juniper seedlings.