New Mexico has in the neighborhood of 70,000,000 acres of land chiefly valuable for grazing livestock. About 18,500,000 acres are found in the southern tier of low-rainfall counties. The importance of this vast area in the economic life of New Mexico may be realized when it’s known that an estimate by the Bureau of Markets and Crop Estimates places the number of cattle in southern New Mexico at 435,000 head, or about 30 per cent of the total in the state. Investigations in range cattle management have been conducted at the Jornada Range Reserve since 1915 by the U.S. Forest Service in cooperation with C.T. Turney, a practical stockman of long experience in the Southwest. Periodic droughts, varying from 1 to 4 years in duration, may occur every 7 to 10 years and play such an important part in range production in the Southwest that any system of range management must take in consideration this factor. The investigators have endeavored to work out an economic system of management for range and stock which would maintain a good breeding herd, regardless of the drought factor and, at the same time, secure highest productivity of the forage and its proper use.