I don't have any scientific proof, but yep, when I was a kid, I always thought it was Jerseys for high butter fat (richest milk), Holsteins for highest volume, and Guernseys for the middle ground.
Of course even the dairies milked by hand when I was a kid, and when we visited Dad's old buddy at the Guernsey dairy, we helped with the milking and they had certain cows on which they put the "kickers" before starting. I guess
this is what you're talking about and I've never seen one before. What was used when I was a kid was
cow kickers that some, in more recent times, called hobbles, and they were. But my dad refused to use such or allow me to with our cows. He said once you start using them, you have to use them all the time. Instead, he said you break the cow of kicking. And he wasn't too gentle about it either.