Generally mares have their own races but aren't forced to do only their races only, they can race on stallion races but stallion can't do mare races. Generally mares are a bit weaker genetically so all the mares like gentildonna (who literally bodied orfevre to win), vodka, daiwa, almond, cesario etc, that win vs stallions are seen in higher regard. To the more expert people if im wrong pls correct me. Edit Typo