The Canadian Wheat Board is standing by an advertisement that has lassoed controversy on the Prairies.

The ad features a 1969 print called "Hi-Ho, Silver," which shows a young woman in a cowboy hat and skirt straddling a fence.

The caption says: "Still on the fence?" and encourages farmers to choose the wheat board for marketing grain.

Dayna Spiring, the board's chief strategy officer, says the vintage image is meant to be edgy and get attention, but it's not intended to offend anyone.

Spiring says it reflects that some farmers haven't decided how to market their grain.

The National Farmers Union is questioning what an image of a long-legged woman straddling a fence has to do with selling grain.