Dairy can compete henceforth, utilising recent negotiations initially (5)
I believe the answer is:
churn
'dairy can' is the definition.
'compete henceforth utilising recent negotiations initially' is the wordplay.
'initially' says to take the initial letters.
The first letters of 'compete henceforth utilising recent negotiations' is 'CHURN'.
(Other definitions for churn that I've seen before include "Large milk vessel" , "Stir vigorously" , "Shake" , "Large metal milk container" , "boil" .)