I don't run with the dog as he has medical problems but as a general rule of thumb I would do exactly what you say.

But on the one occasion things got way out of control none of it made any difference.

It just goes to show how one experience can be so traumatising that it changes your outlook on things. Like a switch in the brain I guess.

Personally I still think that there have been enough instances of aggression with cows that farmers should be forced to take a more responsible attitude. Currently they only have to take more precautions with a solitary bull. It wouldn't have that great an impact on what they do to take measures to protect other land users. A moveable battery powered electric fence in fields where there are young'uns, that's all. I don't think that's a lot to ask to save lives and stop instancs of aggression.