"Square pegs don't go in round holes"
The same goes for cattle;
Cows and calves shouldn't be pushed down an alley together.
So before anything gets worked, it gets sorted.
It's just safer that way.
Most of the time if the cows are on the north side of the freeway, the guys will bring the group that needs to be worked to what we call the "white corrals". There, they'll peel the cows from the calves and sort them into one pen, while the calves go by and are staged in a second pen.
On this day, once the calves were sorted from the cows, the guys needed to sort our Charolais calves from the Double M calves because we were doing different things to each set of calves.
We say when it comes to sorting cattle that "slower is faster" and it really is. The guys stay very quiet, and use their bodies to pressure calves toward the gate. Basically, if you want a calf to go one way, you put pressure on it to go the opposite way and then the "release" of getting away usually drives the calf right to the gate you want it to go out of.
That's what Jack is doing above; he used his body to put pressure and push the white calf towards the corner of the pen in the left hand corner of the photo, and then when the calf turned to try to get away, it went behind him and out the gate in the right hand corner - which was exactly what he wanted it to do. When they were done sorting, all of the white calves were waiting patiently in the alley, and the second set of Double M calves remained behind and the guys could evaluate them and decide what they wanted to keep as bulls and what they wanted to cut. (Most of the bull calves are banded when they're born, but if they're AI sired and Clint thinks they have merit, he'll leave them alone and then they evaluate them before weaning to decide if they should stay a bull or be cut and become a steer.)
No hooting, no hollering, no jumping.
Just nice & easy sorting and sifting.
Because it's important to keep the calves calm while they're being sorted - the dogs stay out of the way and get to rest outside of the pens. They're accustomed to this, and usually find a water trough to jump and cool off in before they hang out on the sidelines until they're needed.