In several countries horse racing is a popular sport with as an important aspect for the public: gambling on the winner with monetary prices. It is comprehensible that for speed the heritability is not high: for the sprint and middle-distance 0.12 and for the long distance 0.07. The effects of trainers and jockeys and the circumstances on the racetrack have a major effect on the performance of the horse. Despite a low heritability and a long generation interval, a steady rise in estimated breeding value is observed especially for the sprint and middle-distance as can be seen in the figure below.
