Young cow or bull (4)
I believe the answer is:
calf
I believe this clue is a double definition.
'young cow' is the first definition.
(a calf is a young cow)
'bull' is the second definition.
(thesaurus)
(Other definitions for calf that I've seen before include "beef" , "Bit of leg" , "Is it above the ankle" , "Young seal" , "Newborn cow" .)