Amidst all the hoopla surrounding Zenyatta's retirement and the speculation regarding the identity of her first mate, last year's Horse of the Year has been all but forgotten. Yet Rachel Alexandra also occupies a unique place in racing history, and her broodmare career should be one of some interest.

Four other 3-year-old fillies have been acknowledged as Horse of the Year in the United States, either by consensus of racing historians or in the polls existing prior to the inauguration of the Eclipse Awards in 1973: Beldame (1904), Regret (1915), Twilight Tear (1944), and Busher (1945). However, Rachel Alexandra is the first 3-year-old filly to be named overall champion in Eclipse Award polling. All four continued racing after age 3, but none recaptured the brilliance they had shown earlier, and Twilight Tear and Busher each made only a single start after three before retiring. Only Beldame and Regret managed to win stakes after their 3-year-old seasons, and only Regret won another championship, being acclaimed the best older female of 1917.