Reading around this subject recently it seems to me that to be safe it’s best not to do this at all with dogs. Cows can charge at people with dogs. The advice is that people should let go of the dogs but recent stories suggest that even this isn’t enough to prevent an attack. On most of the walks you can divert around the edges of fields or spot an alternative path. You’re almost certain to be fine if the herd is far away on the other side of the field; the problems seem to come if they are grazing around the path. Of course 99% of the time they just ignore you, or glare impolitely. But I suggest stay well clear even if without dogs. If with a dog, divert. On the walks at KWNL paths only cross fields with cows in them on the Chiddingstone walk (often but usually very far away on the other side of the field), Underriver walk (sometimes), and very occasionally on the Fackenden Down walk at Magpie Bottom and the top of the Down.