How we cite our quotes:
My comfort came from Topthorn, who [...] would lean his great head over the stall and let me rest on his neck. (6.2)
Horses can be imposing creatures sometimes. But to their friends, both human and horse, they can be tender and gentle. Like people, they have all sorts of sides to their personality.
Topthorn, I noticed, always shook his head in the water before he started to drink so that alongside him I was showered all over my face and neck with cooling water. (6.4)
This is a little maneuver Topthorn does to show how special Joey is to him. Remind you of a secret handshake or something that you have with your friends?
[Captain Nicholls] was always light on me. And there was always some warm word of encouragement or gratitude after a long ride. (6.7)
Nicholls doesn't see Joey as property or a tool, but as a friend. Even though he has to use him to ride, Nicholls still thanks Joey for his service. Some captains don't even do that to their men.