Remove liquid from one local dairy farm’s Jersey, perhaps (9)
I believe the answer is:
bailiwick
'jersey perhaps' is the definition.
(Jersey is officially the Bailiwick of Jersey)
'remove liquid from one local dairy farm's' is the wordplay.
'remove liquid from' becomes 'bail' (as in bailing out a boat).
'one' becomes 'i' (Roman numeral).
'local dairy farm' becomes 'wick' (dialect term for a dairy farm).
'bail'+'i'+'wick'='BAILIWICK'
(Other definitions for bailiwick that I've seen before include "Area of interest" , "legal official's jurisdiction" , "special field" , "Jurisdiction of a bailiff" , "Jersey" .)