Long-haired ox (3)
I believe the answer is:
yak
'long-haired ox' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for yak that I've seen before include "Tibetan creature" , "Shaggy Tibetan ox" , "Domesticated ox" , "Tibetan ox - chatter" , "Wild ox" .)