Black __ (cattle breed) (5)
I believe the answer is:
angus
'black cattle breed' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for angus that I've seen before include "Scots man's name" , "Steer" , "Aberdeen . . . . ., breed of cattle" , "man" , "Scottish cattle area" .)