There are many reasons to teach dogs new skills. Training helps to build the trust relationship between the trainer and the dog, but there are other reasons to train. One reason for teaching these two behaviors is that they are "incompatible" behaviors in that a dog responding to the cue cannot, at the same time, do something like chase livestock. Here are some things to consider.
Dogs generally like to do something rather than stop doing something.
Dogs do what is immediately rewarding to them.
Dogs don't like to get into trouble.
This is wonderful information because it gives a hint as to how to effectively teach a dog.
Here's a scenario for you: My dog is chasing sheep.
If I yell at my dog to stop he might, or he might not, stop chasing the sheep. Yelling at him will damage my relationship with my dog; he may conclude that sometimes I become untrustworthy and he may avoid me in the future. He may also decide chasing sheep isn't a good idea while I am around, so let's wait until later.
If I have taught my dog Touch or Look I can ask for either behavior. My hope is that it breaks the focus of the dog just long enough for me to try to be more fun than chasing sheep. Remember, the dog is going to go for what is the most fun. If I have a tight relationship with my dog he likely is happy to be near me. When I ask for Touch and the dog comes flying I turn into a party! Yea dog! Lots of quick cuddles. Then we quickly move off to do something else, like a brisk walk together in the other direction.
My dear Cameo had a few periods in her adolescence where she could have gotten into trouble with different management, as most young dogs do. In her exuberance, she sometimes scattered her sheep. That could have turned into a habit that wouldn't be good for her or for me, so enter Touch and Look. I remember housing Cameo across from her sheep, but not in with them unless I was with her, for possibly a month, and for intermittent periods until she was two years old or so. Then one day she just seemed to get her brain back for good.
Cameo's bouncy behavior was predictable so it was easy to set up situations where she would "make a mistake" with the sheep, which gave me the opportunity to reinforce her partnering with me over and over. To do this I put her in a small field, with just a few sheep, and worked with her for the first ten minutes or so until she settled; then she was fine.
Animals have both muscle memory and learned experiences. The more times a dog is permitted to chase sheep the more that behavior becomes ingrained and difficult to change. It is much easier to interrupt the behavior by rewarding for something else and then demonstrating to the dog how you would like him to conduct himself instead. You might think it's obvious but dogs don't necessarily know calm behavior is what you'd like to have from them around sheep. Just walking quietly around the pasture with your dog for a few minutes can diffuse bouncy behavior long enough for the dog to settle. The more time he spends with sheep with a quiet mentality the more it becomes a habit.
These bouncy behaviors represent a huge opportunity to build relationship with your dog if you participate. These times usually show up at some time in adolescence, off and on, for seeming no reason. These are normal and predictable behaviors; they don't mean you have a bad dog or that you have done something wrong.
The wonderful thing about learning is that animals learn throughout their lives, and that includes humans. Great! Rise to it and experiment with something new. This stuff is easy, I promise. Cameo is such a devoted guardian now that sometimes she won't leave her livestock long enough to eat. She has been mentoring her nine rambunctious adolescent puppies with serene calmness. I am so proud of her and I wouldn't trade her for anything. Training is worth the effort!