Male quadruped breaks barricades (8)
I believe the answer is:
ramparts
'barricades' is the definition.
(ramparts are defensive walls or barricades)
'male quadruped breaks' is the wordplay.
'male quadruped' becomes 'ram' (male sheep).
'breaks' becomes 'parts' (part can mean to split or break up).
'ram'+'parts'='RAMPARTS'
(Other definitions for ramparts that I've seen before include "Defensive walling" , "used defensively" , "Defensive fortifications" , "defence" , "Fortified earth banks topped with parapets" .)