Old Macdonald perhaps going after sheep (6)
I believe the answer is:
ramsay
'old macdonald' is the definition.
The definition suggests a singular noun which matches the answer.
'perhaps going after sheep' is the wordplay.
'perhaps' becomes 'say' (both can mean 'for example').
'going after' is a charade indicator (letters next to each other).
'sheep' becomes 'ram' (male sheep).
'say' put after 'ram' is 'RAMSAY'.
Can you help me to learn more?
(Other definitions for ramsay that I've seen before include "Gordon --, TV chef" , "Gordon -, British chef" , "__ MacDonald, first British Labour PM" .)