Exploit designed, we hear, for girl occupied in cowshed (8)
I believe the answer is:
milkmaid
'girl occupied in cowshed' is the definition.
(someone working in a cowshed)
'exploit designed we hear' is the wordplay.
'exploit' becomes 'milk' (to milk something is to exploit its potential).
'designed' becomes 'made'.
'we hear' indicates a 'sounds like' (homophone) clue.
'made' sounds like 'maid'.
'milk'+'maid'='MILKMAID'
'for' acts as a link.
(Other definitions for milkmaid that I've seen before include "Udder-manipulating girl?" , "Traditional dairy farm worker" , "8th" , "Female in dairy" , "old farm worker" .)