Had he his own ladder? Yes, and a horse! (5)
I believe the answer is:
jacob
'had he his own ladder?' is the definition.
The definition suggests a singular noun which matches the answer.
'yes and a horse' is the wordplay.
'yes' becomes 'j' (I can't justify this - if you can you should believe this answer much more).
'and' is a charade indicator (letters next to each other).
'horse' becomes 'cob' (type of horse).
'j'+'a'+'cob'='JACOB'
Can you help me to learn more?
(Other definitions for jacob that I've seen before include "Father of the twelve patriarchs of Israel" , "He saw ladder" , "He had a vision of a ladder into heaven with angels going up and down it" , "Hebrew patriarch" , "A son of Isaac (Bible)" .)