The cry of a Missouri duck (3)
I believe the answer is:
moo
'the cry' is the definition.
(moo is a kind of cry)
'a missouri duck' is the wordplay.
'a missouri' becomes 'mo' (abbreviation for the US state).
'duck' becomes 'o' (resembles zero - 'duck' in cricket).
'mo'+'o'='MOO'
'of' is the link.
(Other definitions for moo that I've seen before include "Cow's low" , "Cow's sound" , "Low (of cattle)" , "Cartoon sound of a cow" , "Farmyard sound" .)