I was going to write something myself on stress, but then I came across this post Mom wrote on the main Stockmanship.com website. I can’t improve on it, so will just put the link here and encourage you to read it all:
I have come to the conclusion that most livestock don’t feel safe in their home pastures, no matter where they live, which is why, when Bud moved them,they were convinced that the place he left them was safe and the place they wanted to be. The increase in production and the decrease in illness bolsters my feelings on this. The fact that it makes the stock easier to handle and utilize your pastures better is frosting on the cake. Bud felt that the modern way of moving animals with feed has created neurotic cows that instead of the cow taking stress off of her calf, actually puts stress on it. Read the rest here.