Note from Tina: As this topic often comes up in questions and Facebook posts about stockmanship, I went to the source, Mom, for some more information about using a Bud Box. Here’s what she has to say:
The Bud Box is a philosophy rather than a set of dimensions. People usually don’t have any problems getting animals to “break back” by them when they are trying to drive them. This philosophy is behind this process of encouraging animals to CHOOSE to walk into an alley for either processing or loading. The animals, at some point, are pressured back away from the entrance to the alley, they “get by” the handler, and go up the alley.
Of course, a rectangular Bud Box works best. As they come into the box past the alley, they will turn when they hit the end, want to go back the way they came, can’t as the gate is closed, and they see the handler near the entrance to the alley who then takes one step (or just leans) towards the lead animal (moving reverse-parallel to animals puts pressure on them to speed up past you). Since they want to keep their eye on you, they will naturally curve around you and go into the alley. From this position you can step reverse-parallel to speed them up, back-up parallel to slow them down.
This can be done with a straight-through system if they balk at going in the alley by just walking through the cattle (or stepping outside the pen to get to the other end) and pressuring them against the gate they just came in. When they see they can’t go that way, they will then be in the right frame of mind so you can now work them just like you were in a Bud Box.
You can also do this with a tub, though you should use a cat-walk rather than be inside as there’s no room for you to be in the proper position in most tubs (and it can be dangerous). Put the animals in the tub, close the gate on the most open latch (so they have the most room to turn around), move up to the alley, and start pressuring the animals against the back of the tub. They will choose to go around you and up the alley.
The last few years there has been discussion on “improving” the Bud Box by putting the gate they go through into the box on an angle. These diagrams below show how this is not an improvement, in fact, it is a detriment. If you are going to the back of your box and trying to force the animals into the alley, maybe that angle will help. However, if you are using the Bud Box as designed, you will not be able to work it properly with the gate on an angle. These two diagrams show the difference. When you angle the gate you are taking room away from the handler that he may need. One feedlot Bud worked with made this “improvement.” When loading trucks horseback one day the cattle actually backed the horse and rider up the chute. They immediately squared the Bud Box up and didn’t have any further problems.
Read more about building and using a Bud Box here.