You need to visit this thread on the difference between reining and cowhorse 'turn-arounds'. The Difference Between a CowHorse Turnaround and a Spin
Then, if you drop down to my post (I think it is # 9) you will see Boyd Rice starting a 2 year old on the kind of roll-backs a horse has to do to work a cow.
I think the video of Buck is a really lousy example of a cutter/cowhorse turn-around. It is a hybrid cross of a reining turn-around and a backing without stepping behind. It actually shows a horse trying to do a reining type spin while the rider is not letting the horse have the forward movement he needs. I makes the horse switch his hind pivot foot and hop like I said would happen if the horse is not low in front, 'flat' and not keeping enough forward motion.
I found a video of Boyd Rice who I consider to be the best horseman and all around trainer out there today. If you have not heard of him, He has won the Snaffle Bit Futurity at Reno, the NCHA Super Stakes and Derby and this year won the 'World's Greatest Horseman' event. I think he has almost $4 million in earnings and is still in his 40s. He is pure poetry on a horse and I think his videos are great.
He is a short clip showing how to start backing a horse into a true rollback where the horse steps behind himself. He is doing the 'backing in a circle' that I talked about on this baby.
Here is his website -- Rice Performance Horses | Boyd Rice
If you want a horse to learn to 'hold' a cow, you:
1) Make the horse stop straight
, shoulder to shoulder to the cow.
2) When the cow turns and goes the other way, back him up 1 or 2 steps, straight
3) Roll him around slow -- never hurrying him up in the turn-around -- NEVER.
4) Then, when he is all the way around, hurry him up to catch up to the cow.
This is why a flag or a single cow in a large round pen work so well. The cow (or flag) is always there and the horse can always hustle and catch up to it without losing it back to a herd.
Any good cutting or cowhorse prospect will start speeding their turn-arounds up by themselves if they keep having to play 'catch-up.
If you back him up like in the video of Boyd Rice, he will stop making those little circles when he changes directions.