Breed of cattle and a Channel Island (8)
I believe the answer is:
guernsey
'breed of cattle and a channel island' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for guernsey that I've seen before include "off the Needles?" , "Source of milk" , "Lyric poem" , "Cow - sweater" , "Breed of cattle and a Channel Island" .)