I really like your character designs. The butcher's exaggerated ugliness is a hoot (and his chubbiness helps set up the joke at the end really well), and the cow's stick-thin legs coupled with its huge udder make for a funny combination! The animation was colorful, clean, and attractive, and I liked the sound effects too. One single complaint: while I laughed at the opening joke with the butcher shop's sign, it went on for too long. It shouldn't have looped three times over, because in a short film, that's long enough for the joke to get old- it should have run only once, enough for the audience to see the setup, see the punchline, laugh, and move on.
Just my two cents, though!