During the winter grazing seasons from 1946 to 1953, studies were carried on throughout the desert ranges of western Utah to determine nutritive content and digestibility of range forage plants.
These desert areas receive about 7 inches of precipitation annually and the vegetation consists, chiefly, of saltbush and sagebrush types.
The average floral composition of the desert areas studied was about 74 percent browse, 25 percent grass, and 1 percent forbs. However, on some areas there was more grass than browse and, on still others, large quantities of forbs were present, primarily Russian-thistle.
Digestion trials were carried out under normal range conditions by the use of the lignin-ratio method. Desert ranges in winter were found to be from borderline to decidedly deficient in digestible protein, phosphorus, and metabolizable energy. Diets containing appreciable quantity of browse furnished more than 10 times the minimum requirement of carotene, whereas, grass ranges were decidedly deficient in this respect.
Cook, C. W.; Stoddart, L. A.; and Harris, L. E., "Bulletin No. 372 - The Nutritive Value of Winter Range Plants in the Great Basin as Determined with Digestion Trials with Sheep" (1954). UAES Bulletins. Paper 331.