President Ulysses Grant was an avid horseman. Having been a military man prior to his Presidency, horses were his pet of choice before, during, and after his time in the White House. This love for horses was passed on to his children. His daughter, Nellie, had horses of her own in the stables; two mares named Jennie and Mary.
Unfortunately, little is known about these two mares. It is mentioned in various places that perhaps Mary was used more for riding while Jennie was at least in part a brood mare, but these are rumors. Most of their information has been lost to history. However, Nellie Grant inherited her father’s passion for horses, and it seems reasonable to assume that Jennie and Mary both received excellent care and a great deal of love from the President’s daughter.