The cry of many a pooch (3)
I believe the answer is:
yap
'the cry' is the definition.
(thesaurus)
'of many a pooch' is the wordplay.
'of' indicates the answer is hidden within the clue.
'YAP' is hidden in the letters of 'many a pooch'.
(Other definitions for yap that I've seen before include "Shrill bark; talk at length" , "Complain shrilly" , "Small dog's sound" , "High-pitched bark" , "Bark incessantly" .)