Cattle Diets in the Blue Mountains of Oregon, I. Grasslands

Abstract

Esophngeally iktulated cows were used to determine cattle diets on grassland range in northeastern Oregon in 1976,1977, and 1978. Idaho fescue, bluebunch wheatgrass, and Sandberg bluegrass were the most common species in the diets. Forb consumption declined while grass consumption increased with seasonal advance from late spring to fall. Food habits depended hugely on phenological development of forage species. Forbs were preferred over grasses early in the grazing season; then afterforbs reached maturity, cattle were selective for the plants that remained green. Diet shnilarities were compared between periods within years, and between years within periods. When diets were pooled into late spring, early summer, late summer and fall groups, late spring diets were least similar to the others. Diet variation from year to year was also less later in the grazing season. Utilization of Idaho fescue and bluebunch wheatgrass should be considered in grazing management decisions on grasslands in the Blue Mountalns.