Child-minder to attack farm animal (5,4)
I believe the answer is:
nanny goat
'farm animal' is the definition.
(I've seen this before)
'child-minder to attack' is the wordplay.
'child minder' becomes 'nanny' (I've seen this before).
'to attack' becomes 'goat' (go at).
'nanny'+'goat'='NANNY-GOAT'
(Other definitions for nanny goat that I've seen before include "Billy's partner?" , "Female farm animal" , "Butter" , "milk producer" .)