Barbed Wire Fencing

Barbed wire, also known as barb wire is a type of fencing wire constructed with sharp edges or points arranged at intervals along the strand(s). It is used to construct inexpensive fences and is used atop walls surrounding secured property. Barbed wire was the first wire technology capable of restraining cattle. Wire fences were cheaper to erect than their alternatives and when they became widely available in the United States in the late 19th century they made it affordable to fence much larger areas than before. They made intensive animal husbandry practical on a much larger scale.
(Wikipedia Reference)