I LOVE this joke--Cluin posted a different version above.

Sven got a new cow & when he inspected her, he pulled on each teat. As he did this the cow farted with each pull.

He wanted show his friend, Ollie the new cow. He told Ollie to pull on the teats & see what happens. The cow farted with every pull. Ollie says: "You got this cow in Minnesota!" Sven was surprised and asked "How did you know?" "My wife is from Minnesota" replied Ollie.