Cow

Cows appear in various The Legend of Zelda games. They are Hyrule's primary source of milk, and are kept in the land's various farms.

Ocarina of Time
In Ocarina of Time, cows can be found all over Hyrule. Many can be found in various holes and caverns (what business they have there is unknown), but a few are also kept at Lon Lon Ranch, and tended to by Talon and Malon. In this game, a free bottle of milk can be obtained by playing Epona's Song in front of a cow. They will appreciate the song, and give you milk for it.

Majora's Mask
Cows are also featured in Majora's Mask. They are not as commonly found around Termina as they are in Hyrule, but there are several in Romani Ranch. Much like in Ocarina of Time, Epona's Song can be played to a cow, and they will produce milk to give you for free.