Recovery skills, as the name implies, restores your uma’s HP during the race. Golden recoveries will restore 5.5% of your HP, while white recoveries restore 1.5%. As such, golden recoveries are far more important than white ones.
The best recovery skills are the ones that restore HP at a consistent time, such as Gourmand seen above. Corner recoveries are also very good. Straight recoveries aren’t ideal, as they could trigger at the start or the end of the race where they have less impact.