Roundups of cowboy

Large numbers of cattle lived in a semi-feral, or semi-wild state on the open range and were left to graze, mostly untended, for much of the year. In many cases, different ranchers formed "associations" and grazed their cattle together on the same range. In order to determine the ownership of individual animals, they were marked with a distinctive brand, applied with a hot iron, usually while the cattle were still young calves.

The primary cattle breed seen on the open range was the Longhorn, descended from the original Spanish Longhorns imported in the 16th century, though by the late 19th century, other breeds of cattle were also brought west, including the meatier Hereford, and often were crossbred with Longhorns.

In order to find young calves for branding, and to sort out mature animals intended for sale, ranchers would hold a roundup, usually in the spring.

A roundup required a number of specialized skills on the part of both cowboys and horses. Individuals who separated cattle from the herd required the highest level of skill and rode specially trained "cutting" horses, trained to follow the movements of cattle, capable of stopping and turning faster than other horses.

Once cattle were sorted, most cowboys were required to rope young calves and restrain them to be branded and (in the case of most bull calves) castrated. Occasionally it was also necessary to restrain older cattle for branding or other treatment.

A large number of horses were needed for a roundup. Each cowboy would require three to four fresh horses in the course of a day's work.

Horses themselves were also rounded up. It was common practice in the west for young foals to be born of tame mares, but allowed to grow up "wild" in a semi-feral state on the open range.

There were also "wild" herds, often known as Mustangs. Both types were rounded up, and the mature animals tamed, a process called horse breaking, or "bronco-busting," (var. "bronc busting") usually performed by cowboys who specialized in training horses.

In some cases, extremely brutal methods were used to tame horses, and such animals tended to never be completely reliable. However, other cowboys became aware of the need to treat animals in a more humane fashion and modified their horse training methods,often re-learning techniques used by the vaqueros, particularly those of the Californio tradition.

Horses trained in a gentler fashion were more reliable and useful for a wider variety of tasks.

Informal competition arose between cowboys seeking to test their cattle and horse-handling skills against one another, and thus, from the necessary tasks of the working cowboy, the sport of rodeo developed.