Over the years we've had a few cowboys with pretty good Hangin Tree dogs.
Our cowboss in California has some outstanding dogs that sort of similar, kind of a mix of mostly McNabb with some Kelpie, a little Catahoula and just a pinch of Pit. Really good dogs with a big motor, good voice in the brush and strong to the head on feisty old cows while still being soft enough to not get too strong on a calf.
We do allow our cowboys to have dogs but all dogs and more importantly, all dog handlers are not created equal so it's on a case by case basis as to which cowboys we allow to use dogs and which we don't. The old saying that a good dog is worth 2 mounted men is very true but it's also true that a bad dog cancels out 2-3 mounted men.