Six-furlong races at Prairie Meadows were shortened to 5 1/2 furlongs Aug. 2 because of an uneven spot in the backstretch chute."There have been reports of a little dip," racing secretary Dan Doocy said. "They've worked on it in the past, but it hasn't gotten any better. (Track superintendent) Lamont Marks and (facilities director) Bob Gorla decided to go in and fix it. Hopefully, it's a one- or two-day deal."A furlong is an eighth of a mile, so the decrease meant three races listed in the official program and Daily Racing Form as six-furlong events were shortened by a sixteenth of a mile. There is no racing Aug. 3, and when entries were taken for the Aug. 4 program, 5 1/2-furlong races were carded.