@andyb My father used to herd cows for milk, and he described their nature as exactly this. They are just big lovely dogs that don't know their own strength, but can learn.

He used to play a lot with them, and if you were rough, they were rough, but if you were gentle, they would as well. He eventually left the business because the didn't have the heart to deal with the whole thing (you eventually have to sell them to slaughter, and that would always break his heart).