Litter boxes made at first for footwear (5)
I believe the answer is:
pumps
'for footwear' is the definition.
(pumps is a kind of footwear)
'litter boxes made at first' is the wordplay.
'litter' becomes 'pups' (I've seen this in another clue).
'boxes' is an insertion indicator (the outside letters must 'box' inside letters in).
'at first' indicates taking the first letters.
The initial letter of 'made' is 'm'.
'pups' going around 'm' is 'PUMPS'.
(Other definitions for pumps that I've seen before include "Plimsolls" , "Light dancing shoes - force air into" , "needed by cyclists" , "causes of inflation?" , "Moves fluid or gas by pressure or suction" .)