Jan Ohlsson (Emil) revealed in an interview well after the fact (while promoting some horror flick he appeared briefly in), that the pig actually seemed to very much dislike being treated like a pet and towed around by him, and kept biting him during filming. See more
[Emil has promised to preach soberness and is smashing a bunch of bottles of Cherry wine made for Mrs. Petrell
Emil! What are you doing?
I'm preaching for soberness. And I'm starting with Mrs. Petrell.