What is the feud between the Burdens and the Shimerdas? How do they get reconciled to each other?

This is from the horse collar episode. Ambrosch had borrowed a horse collar. Jim and Jake rode over to fetch it. Ambrosch pretends he had not borrowed such a collar. Ambrosch is angry and brings an old ratty one. There is a physical altercation between Jake and Ambrosch. Antonia tells Jim they are not friends anymore.