Although farming preceded ranching in Colorado and has long since surpassed it in importance, the great cattle ranches of the seventies and eighties first gave agriculture any considerable weight in the State's economy. Stock raising began in the fall of 1858 when a prospector turned his oxen loose to shift for themselves on the grassy flats now occupied by Denver. When the animals were rounded up in the spring, he found that they had grown sleek and fat. With the discovery that cattle could be pastured on the plains, great herds of Texas Longhorns were driven northward into the lower Arkansas Valley and other sections of the plains. The penetration of transcontinental railroads soon opened up new cattle country in the mountain parks and on the Western Slope. Thousands of cattle were loaded for eastern markets at Antonito, Lamar, Julesburg, Sterling, Brush, Walden, and other Colorado shipping centers.

As there were no fences in early days, cattle sometimes strayed as far as two hundred miles from their home ranges. Cowboys were hired to guard the herds and keep them on the richest available pastures. Every spring the calves were rounded up and branded; every fall the fattened steers were rounded up for market. The round-up, a community enterprise, brought together cowboys and stockmen from dozens of ranches. Organized gangs of thieves preyed upon the cattle and sometimes stole entire herds. Cowmen waged a relentless war against these rustlers and finally succeeded in breaking up the larger gangs.

By 1879 cowboys were riding herd on 855,000 head of cattle in Colorado, chiefly on great open ranges, part of the public domain. At this period the cattle industry was concentrated in the hands of large ranchers whose herds numbered from ten to fifty thousand head. Their ranches were of corresponding dimensions; the "JJ" ranch of the Prairie Cattle Company in the lower Arkansas Valley extended fifty miles east from La Junta and seventy miles south into New Mexico and Oklahoma, embracing 2,240,000 acres. English and Scottish interests controlled many of the larger properties.

Until the Leadville boom of 1879-80 cowboys were the only large body of wage earners in the State. Isolated in small groups during the greater part of the year and sharing with their employers the hazards of frontier life, they usually regarded the ranch as in part their own, as it often was, for many cowboys owned small herds of cattle and horses that grazed on the open range along with the stock of their employer.

The reign of the powerful cattle barons was comparatively brief, for the ranges were soon overstocked. In the hard winter of 1886-7 fully half of their stock perished and the succeeding drought took a heavy toll. Meanwhile, homesteaders had been taking up more and more claims, drastically reducing the extent of the open range, and by the close of the century cattle raising had become a scattered and usually small-scale enterprise. Shorthorns, Herefords, and other breeds of better beef stock replaced the hardy but scrawny Texas Longhorns. Today, a few large ranchers still own immense tracts of land but more of them lease pasture from farmers and the Federal Government. In 1939 Colorado was credited with 1,447,000 head of cattle, of which 243,000 were milk stock.

Sheep were driven into Colorado early in the seventies, and by 1879 there were 2,000,000 on the plains in spite of the opposition of cattlemen, which occasioned some violence. The latter quite naturally objected because sheep clip a range so close that cattle cannot feed on it. Subsequently, great bands of sheep were driven to the Western Slope, which is still the main sheep range in Colorado. After the World War many farmers in the northern plains section began purchasing range lambs from other States and bringing them to their fields to be fattened for market (see Tour 13) on a diet of alfalfa, silage, beet tops and pulp from the sugar refineries; the area around Fort Collins is now the most important spring lamb feeding ground in the country. On January 1, 1939, Coloradoans were herding 2,810,000 sheep, of which 1,090,000 were on feed.

In addition to cattle and sheep, the State raises hogs, horses, mules, poultry, and other livestock. Cattle and sheep, however, represent more than three-fourths of the inventory value of all livestock on ranches and farms. On January 1, 1939, the value of all farm livestock was $87,600,000.