Racing without shoes
 

Mr. Wadleigh runs 3rd while not wearing shoes in the first turf race ever run at the New Evangeline Downs.

http://www.drf.com/drfPDFChartRacesI...=20090408&RN=3

an ounce on the hoof is worth a pound on the back

Horseshoes are designed to protect a horse's hoof from hard and uneven surfaces, like cobblestones, paved roads, rocky trails, etc, and to prevent excess wear when they are doing heavy labor. Weren't used before c.500 AD. Most racehorses don't have to deal with said surfaces these days, but universal shoeing is a cultural habit. Not all horses can go barefoot, either, since some horses have weaker hooves than others (name your own names here). Also requires more day-to-day awareness of hoof health.