Cattle Diets on Semidesert Grassland: Botanical Composition

Botanical composition of cattle diets on semidesert rangeland was studied by microhistological techniques. Cattle consumed 56% of all species available. Dietary portions of grasses, forbs, shrubs, and unidentifiable plants averaged 45, 32, 19, and 6%, respectively. Composition of diets changed with seasons. Grass contents of diets were highest in summer and lowest in spring. Mesa dropseed was the most common species in diets. Perennial grasses represented dependable sources of forage, but never comprised more than 50% of the steers' diets in any season, and should not be used as the sole criterion for estimating forage production or determining stocking rates. Shrub portions were highest in spring when soaptree yucca was grazed almost exclusively. Forb fractions of diets varied little among seasons but were highest in winter. Forbs and shrubs comprised over one-half of the diets in certain seasons and should be grazed in these seasons if full benefit is to be derived from them. Preference ranking of forage plants evaluated selectivity and palatability but preference trends were inconsistent and most affected by species availability.