One smoke-tinged July morning on Horse Prairie — a plateau of big sagebrush and dusty washes overlooking Horse Prairie Creek in southwestern Montana — a man sat at the helm of a skid-steer loader.

“Wire strength is largely a factor of its carbon content,” said Harold Shipman, territory manager for Stay-Tuff Fence Mfg. Inc. “As carbon content increases, density of the wire also increases. Low ...