This is a picture of a cowboy riding a bucking horse. Professionals do this for a living. They enter a rodeo to ride one of these bucking horses. If they win they will get many different prizes such as money and belt buckles. These bucking horses have never been rode, and they have a strap in their flank which makes them buck. Normal cowboys do not want their horses to buck.
This is a rancher herding cattle, more than likely to brand them or doctor them. Eventually a cow’s calf will get big enough to live on its own. So the cowboys have to separate the calf and the cow, this is called weaning the calf off of the cow.