In Utah, a vast industry of livestock grazing, which is the backbone of the state's agriculture, has arisen during the past 75 years. Range land furnishes between 6 and 7 million animal unit months of forage to some 2 1/2 million sheep and 275 thousand range cattle. Income from meat, wool, and range livestock sales in Utah is about $15,801,500 annually, of which $11,700,000 is calculated to be obtained from range lands exclusive of cultivated pastures.
These range lands can be used economically in no other way than by grazing livestock and, because of heavy winter snows and protracted dry periods, most of these lands are distinctly seasonal in character. Livestock, then, must be supported for Iong periods upon farm lands or upon other range lands. The animals must be driven or shipped over distances sometimes well in excess of 100 miles from one range to another. The specific seasonal nature of these lands makes important the study of seasonal variations in forage value. That animals can make the most efficient use of the range lands, it is important to understand the forage value, the balance of various chemical constituents, and the importance of deficiencies in the diet of animals existing wholly upon these native plants.
Stoddart, L. A. and Greaves, J. E., "Bulletin No. 305 - The Composition of Sumer Range Plants in Utah" (1942). UAES Bulletins. Paper 267.