AT: "ar" The Kentucky Derby was a horse racing competition that took place in Kentucky on Earth during the 19th, 20th, and 21st century.
According to Leonard McCoy, there was an old saying where he came from: "if you're going to ride in the Kentucky derby, you don't leave your prized stallion in the stable." McCoy cited this saying to Spock following the exile of James T. Kirk on Delta Vega. Spock found McCoy's line to be a "curious metaphor", stating that "a stallion must first be broken before it can reach its potential," which also described his observations of Kirk. (Star Trek)