>>280588707I don't think so. But even if that was the case, that's like asking "why race horses when cars are faster". A lot of the big races in the classics are restricted to colts or fillies, such as the Triple Crown and the Triple Tiara, but there are mixed races, too.
For example, Nishino Flower was the only one to ever beat Sakura Bakushin O in a sprint race and basically saved her farm from bankruptcy due to the demand for her foals.
Haru Urara is probably an even more famous example of a female racehorse, though for different reasons.
>>280589339>sell horse semenThey don't use artificial insemination for thoroughbred racehorses. They have to mate naturally and in front of witnesses to verify the lineage. The owners of the studs rent them out for this purpose. Golshi sired 418, but that's nothing compared to the work Agnes Tachyon had to do considering those 2,800+ foals he sired.
Also, the X-factor is basically superstition and myth. Actually putting their genetics under a microscope for eugenics would kill the global racehorsing industries; hence why there's no artificial insemination or genetic modification allowed.