I think this is the closest thing to Hirofumi Suzuki's work on the film but there's a vague description (probably from gengashuu?) on Takashi Kawaguchi's wiki page that may or may not include this scene: 鞍を取り付ける所～仔太郎の乗馬練習。

To my eyes, the animator changes (to Kawaguchi) a couple cuts after this upload. But it's at least unsure enough to withhold the tag.