A cattle grid – also known as a stock grid in Australia; cattle guard, or cattle grate in American English; vehicle pass, or stock gap in the Southeastern United States; Texas gate in western Canada and the northwestern United States; and a cattle stop in New Zealand English – is a type of obstacle used to prevent livestock, such as sheep, cattle, pigs, horses, or mules from passing along a road or railway which penetrates the fencing surrounding an enclosed piece of land or border. It consists of a depression in the road covered by a transverse grid of bars or tubes, normally made of metal and firmly fixed to the ground on either side of the depression, so that the gaps between them are wide enough for an animal's feet to enter, but sufficiently narrow not to impede a wheeled vehicle or human foot. This provides an effective barrier to animals without impeding wheeled vehicles, as the animals are reluctant to walk on the grates.