Ladies and gentlemen carrying father up and down over peak in America, spotted horse (9)

'spotted horse' is the definition.
(I've seen this before)

'ladies and gentlemen carrying father up and down over' is the wordplay.
'ladies and gentlemen' becomes 'loos'.
'carrying' is a charade indicator (letters next to each other) (in a down clue, the bottom letters carry others).
'father' becomes 'pa' (pa can mean dad or father).
'up and down' becomes 'apa' (I can't justify this - if you can you should give a lot more credence to this answer).
'over' means one lot of letters goes inside another.
'loos' put after 'pa' is 'paloos'.
'paloos' going into 'apa' is 'APPALOOSA'.

'peak in america' acts as a link.
This may not be right. Some or all of it may be part of another bit of the clue.