She soon fell in love with dressage, a fussy Olympic sport that is also called “horse ballet.” In dressage, a horse moves in delicate, dance-like steps to music as the rider, formally clad in top hat and tails, imperceptibly guides the animal.

Because it requires tremendous muscle control, dressage also provided Romney unexpected therapeutic benefits…

Dressage is not for the faint of wallet; it requires healthy outlays of cash for upkeep, training, transportation and veterinary care. It attracts some of the world’s richest people — the daughter of billionaire New York Mayor Michael R. Bloomberg competes. Yahoo co-founder Jerry Yang and his wife own dressage horses.

A spokeswoman for the Romney campaign would not discuss the costs associated with Ann Romney’s horses. “We are not required to disclose this information,” said Amanda Henneberg in an emailed statement.