Being a girl is tough in the racing industry although you can be just as good or even better than your male companions, rarely do you get the recognition. This is just what happened to Zenyatta.
Although placed in the running for Horse of the Year, she did not stand much of a chance again Big Brown or Curlin (both males). If she was a stallion, having a undefeated season, let alone an undefeated career, would have made her a shoe in for the honors. In the filly and mare races Zenyatta has won all the major races, including the Breeder's Cup Ladies Classic.
Now as a five year old she is expected to just as well as her previous seasons. Perhaps this time she won't be discounted or overshadowed by the boys.