Reportedly perceived some cows (4)
I believe the answer is:
herd
'some cows' is the definition.
(group of cows)
'reportedly perceived' is the wordplay.
'reportedly' shows a homophone (sound like).
'perceived' becomes 'heard' (hearing is a kind of perceiving).
'heard' sounds like 'HERD'.
(Other definitions for herd that I've seen before include "Large group of animals" , "Assemblage" , "The rabble" , "Group of, eg, cows" , "Animal group" .)