Final answer:
Marty offered to trade his comic book collection to Judd to ensure the well-being of Shiloh, the dog.
Step-by-step explanation:
The trade that Marty offered to Judd in the story refers to a deal where Marty trades his comic book collection to Judd. This trade was made in an attempt to rescue Shiloh, the dog Marty cares for, and ensure that the dog would no longer have to suffer under Judd’s negligent care. Marty's idea was to offer something valuable to persuade Judd into giving Shiloh a better life.