The old plural of “cow”.  Some Middle English and earlier plurals were formed with and “n” ending (housen = houses, eyen = eyes, oxen).  This word appears in an elven poem, so it gets a double boost in register!

• 09.053 Where the kine and oxen feed!

“kine, n.1.” OED Online. Oxford University Press, March 2015. Web. 20 May 2015.