Carrot

Carrots are used in Ocarina of Time, Majoras Mask and Four Swords Adventures. They are used to speed up your horse for a short amount of time. In Twilight Princess they are taken over by Spurs.

Ocarina of Time
In Ocarina of Time, carrots appear while riding Epona as a meter at the bottom of the screen. They are used to give a burst of speed, and refill gradually over time.

Four Swords Adventures
In Four Swords Adventures carrots can be collected to increase the speed of Link's horse.