Bring down cow perhaps (5)
I believe the answer is:
lower
I believe this clue is a double definition.
'bring down' is the first definition.
(synonyms)
'cow perhaps' is the second definition.
(low can mean to make a mooing sound)
(Other definitions for lower that I've seen before include "disgrace" , "Less high in place or position" , "Let down using rowel" , "Threaten" , "Let or haul down" .)