What's the fastest a dog can wag its tail or butt/tail nubbin?

See subject. A wag means one back-and-forth across midline. Butt shakes are allowed, but in a different category.

Which breeds are fastest? (Assuming an observed mutt is the winner.)

Extra credit if answers are given in Hz.

We never actually timed it, but my old lab/vizsla mix would wag his tail against the furniture so hard it’d bleed, and would then continue wagging to splatter blood all over the place.

Dogs with cropped tails or naturally very short can wag much faster than dogs with a typically long tail.

You got that right! My neighbor’s bulldog (I think English bulldog) wags his tail in the mile-a-minute category. Which is about 60hz, give or take. The dogs rear is wagging, i.e. not so much the tail but the entire hind end his feet can’t even keep still. It’s hilarious actually.

Damn, I didn’t know furniture could bleed.