Rainbow Over the Rockies (1947)

Driving a herd of cattle to market, Jimmy finds the trail has been fenced off by an old friend of his. While the two sides try to settle the matter peaceably, a man from each outfit get together to try and start a range war between them figuring they will end up with the cattle. When cattle are rustled, Jimmy finds the clue, horses with shoes that make tracks that look like cattle.