Heiðrún

In Norse mythology, Heiðrún was the name of a goat which produces mead for the einherjar. She is described in Snorri Sturluson's Prose Edda.

Geit sú er Heiðrún heitir stendr uppi á Valhöll ok bítr barr af limum trés þess er mjök er nafnfrægt, er Léraðr heitir, en ór spenum hennar rennr mjöðr sá er hon fyllir skapker hvern dag. Þat er svá mikit at allir einherjar verða fulldruknir af. - [1]

A goat called Heiðrún stands up [on its hind-legs] in Valhalla biting the buds off the branches of that very famous tree which is called Lærað. From her teats runs the mead with which every day she fills a cauldron, which is so big that all the Einherjar can drink their fill from it. - Young's translation

In the Poetic Edda Heiðrún is mentioned twice. She is described in the Grímnismál in a way similar to Snorri's description.

Heiðrún heitir geit,

er stendr höllo á

ok bítr af læraðs limom;

skapker fylla

hón skal ins skíra miaðar,

knáat sú veig vanaz.

Heithrún, the goat

on the hall that stands,

eateth off Læráth's limbs;

the crocks she fills

with clearest mead,

will that drink not e'er be drained. - LMH's translation

Since Snorri quotes other strophes of Grímnismál it seems reasonable to assume that he knew this strophe too and used it as his source for his description of Heiðrún.

In the Hyndluljóð Heiðrún is mentioned in a humorous way when Hyndla addresses Freyja.

Rannt at Óði

ey þreyjandi,

skutusk þér fleiri

und fyrirskyrtu;

hleypr þú, Óðs vina

úti á náttum,

sem með höfrum

Heiðrún fari.

To Oth didst thou run,

who loved thee ever,

And many under

thy apron have crawled;

My noble one, out

in the night thou leapest,

As Heithrun goes

the goats among. - Bellows' translation

Heiðrún's name is sometimes anglicized Heidrun, Heidhrun, Heithrun, Heidrún, Heithrún or Heidhrún.

References

Bellows, Henry Adams. Translation of the Poetic Edda. Available at [2].
Eysteinn Björnsson (ed.) (2005). Snorra-Edda: Formáli & Gylfaginning : Textar fjögurra meginhandrita. http://www.hi.is/~eybjorn/gg/
Hollander, Lee M. (1962). The Poetic Edda. Austin: University of Texas. ISBN 0-292-76499-5.
Jón Helgason (Ed.). (1955). Eddadigte (3 vols.). Copenhagen: Munksgaard.
Young, Jean I. (1964). Snorri Sturluson : the Prose Edda. Berkeley: University of California Press. ISBN 0-520-01231-3.