| rabbit |
 | A speed horse running as an entry with another, usually come-from-behind horse. The rabbit is expected to set a fast pace to help the chances of its stablemate. |
| racing secretary |
| Official who drafts conditions of races and assigns weights for handicap events. |
| radiograph |
| The picture or image on film generated by x-rays. |
| rail |
| The barrier on either side of the racing strip. Sometimes referred to as the "fence." |
| rail runner |
| Horse that prefers to run next to the inside rail. |
| rank |
| A horse that refuses to settle under a jockey's handling in a race, running in a headstrong manner without respect to pace. |
| rattle |
| Used in the expression, "He likes to hear his feet rattle," a horse that likes a firm turf course. |
| receiving barn |
| Structure used by horses shipping in for a race who do not have a stall at that racetrack. |
| redboard |
| 1) Old-time method of declaring a race official, by posting a red flag or board on the tote board. 2) A mildly derogatory phrase used to describe someone who claims to have selected the winner, but always after the race. |
| refuse |
| 1) When a horse will not break from the gate. 2) In jumping races, balking at a jump. |
| reins |
| Long straps, usually made of leather, that are connected to the bit and used by the jockey to control the horse. |
| reserve |
| A minimum price, set by the consignor, for a horse in a public auction. For example, "The horse did not reach its reserve." |
| reserved |
| 1) Held for a particular engagement or race. 2) Held off the pace. |
| respiratory system |
| Organ system responsible for gas exchange from nostrils to lungs. |
| ridden out |
| A horse that finishes a race under mild urging, not as severe as driving. |
| ride short |
| Using short stirrups. |
| ridgling ("rig") |
| A term describing either a cryptorchid or monorchid. Also spelled "ridgeling." |
| ring bone |
| Osteoarthritis of joints between the pastern bones ("high ring bone") or just above the coronet ("low ring bone"). |
| RNA |
| Reserve not achieved. See reserve. |
| roan |
| A horse color where the majority of the coat of the horse is a mixture of red and white hairs or brown and white hairs. The mane, tail and legs may be black, chestnut or roan unless white markings are present. Starting with foals of 1993, the color classifications gray and roan were combined as "roan or gray." See gray. |
| roaring (laryngeal hemiplegia) |
| A whistling sound made by a horse during inhalation while exercising. It is caused by a partial or total paralysis of the nerves controlling the muscles which elevate the arytenoid cartilages which thereby open the larynx. In severe cases, a surgical procedure known as "tie-back surgery" (laryngoplasty) is performed, in which a suture is inserted through the cartilage to hold it out of the airway permanently. Paralysis almost exclusively occurs on the left side, most frequently in horses over 16 hands high. |
| rogue |
| Ill-tempered horse. |
| rogue's badge |
| Blinkers. |
| route |
| Broadly, a race distance of longer than 1-1/8 miles. |
| router |
| Horse that performs well at longer distances. |
| ruled off |
| See suspend. |
| run down |
| Abrasions of the heel. |
| run-out bit |
| A special type of bit to prevent a horse from bearing out (or in). |
| rundown bandages |
| See bandages. |
