Cows on the footpath

We walked a fair few miles today over Devil's Dyke and then ended up at The Devil's Dyke pub for a few refreshments. I did manage to take some passable landscape images but thought I would include the cows to remind myself of a "debate" between Ken and I about the risks they can pose to walkers.
As an early riser, I listen regularly to Farming Today (so consider myself an authority on all things rural). They occasionally mention something about cows, particularly if they have calves, attacking walkers. Ken assured me that unless they were bulls they were perfectly safe but he didn't hear the growling or see the pawing when we walked through them with the dogs on leads because he was so convinced he was right.
Anyway, if anybody can support my theory let me know. I don't want to know if I am wrong though. ha ha.