Oh right... Taizo— er, MADAO is an incorrigible horse punter.
(Note that the above line is a parody of what Erwin says to Eren. The infamous "Who do you think the enemy is" line, which becomes hilarious when taken out of context.)
I'm sure when Yamatoya-sensei penned that episode he had no idea that the horse he named after a Gintama item for the lulz would wound up becoming Golshi's BFF the best rated horse in the world.