The coat of a gray, roan, or dun might not gleam like a mirror, as will the chestnut, bay, black, or Palomino. Some contend that no external product can replace the shine of a coat that's been rubbed daily. This task takes a lot of elbow grease, or up to thirty to sixty minutes each day for a cleaning routine. For that show bloom, energetic grooming maintains a fine, short coat. The coat's natural oils also attract dirt and dust.
Grooming sweeps dirt from the coat.
With clean skin and a short coat, perspiration will evaporate more freely and the skin will be kept cool. In the summer, horses sweat more during exercise. Sweat can damage the coat when allowed to dry on the hairs. If you turn a sweaty horse out in the sun, the combination of sunlight and salty sweat can bleach the coat. Friction against the skin brings the horse's natural oils to the surface.