Yes I know this - it doesn't stop some rich person breeding a faster race horse. In practice once you have the fastest horse you will be able to race it outside

Yes I know this - it doesn't stop some rich person breeding a faster race horse. In practice once you have the fastest horse you will be able to race it outside the thoroughbred system. Actually even within the registered thoroughbred system it would be possible to use genomic data to improve speed. Due to inbreeding the average thoroughbred carries a large number of null mutatations in minor genes that degrades overall performance. Using genomic data it should be possible to identify which horse should be crossed to remove these mutations. Having said this, it will be a slow and expensive process.