How does he treat the dog?
The narrator treats Tricki with no medicinal treatment but instead focuses on natural recovery. He makes a warm bed for him in a loose box next to the other dogs. For two days, he gives Tricki no food but plenty of water to counteract the effects of overfeeding.
Once Tricki shows interest in his surroundings, the narrator allows him to run about with the other dogs all day, joining in their friendly scrimmages. He ensures Tricki gets an extra bowl at mealtimes and lets him jostle with the other dogs for his share. Through this simple treatment of controlled diet and plenty of exercise, Tricki recovers rapidly without any surgery or medicine.
Explanation
The question asks how the narrator (Mr. Herriot) treats Tricki. The key points from the text are: he gives no medicinal treatment, keeps Tricki on a strict diet (no food for two days, only water), provides a warm bed, and lets him exercise naturally with the other dogs. This contrasts with Mrs. Pumphrey's pampering and overfeeding. The narrator's treatment is essentially letting nature take its course through proper diet and exercise.