The Legend of Zelda: Ocarina of Time 3D Unlockables

A Cow At Link's House
Serves no real practical purpose other than giving you an extra source of Lon Lon milk. The cow will be sent to Link's house in Kokiri Forest but since you do this as an adult then it will only be there as an adult.
UnlockableHow to unlock
CowYou must have Epona. Talk to Malon at Lon Lon Ranch and do the obsacle course. Once you have completed 2 laps under 50 seconds you get a cow.