That has the potential to be great. A couple of suggestions for you:
1. The cow is speaking way too fast to be understood. Slow down when you speak his lines, so they'll come out slower when you speed up the playback to get the chipmunk voice.
2. The animation is a little choppy in places. Your art looks good, but the animation's kind of thrown together in spots. I think you could've done better with that.
3. I'm not sure if there's supposed to be a point. Did I miss something? :)
4. Perhaps some music at the beginning, in the background while they're outside the barn, might make it smoother. It seemed awkward that we entered the scene with no noise at all outside a noisy jamboree...
I think that's it. I like this animation, and I voted to protect... but I'd still like to see some improvements.