In short, a horse-like draught animal is to be presented not long after St Patrick's Day (7)
I believe the answer is:
equinox
'not long after st patrick's day' is the definition.
I can't judge whether this defines the answer.
'in short a horse-like draught animal is to be presented' is the wordplay.
'in short' means to remove the last letter.
'a horse-like' becomes 'equine' (I've seen this before).
'draught animal' becomes 'ox' (I can't justify this - if you can you should believe this answer much more).
'is to be presented' means one lot of letters go next to another.
'equine' with its final letter removed is 'equin'.
'equin'+'ox'='EQUINOX'
Can you help me to learn more?
(Other definitions for equinox that I've seen before include "When the sun crosses the equator" , "TV show" , "it occurs twice a year" , "Vernal/autumnal --" , "Time of day/night equality" .)