We had a problem with our cows getting out almost every night for a week earlier this summer. Just so happened one afternoon went to check them and I saw the calves in the other pasture. They had gone between two strands of electric wire and when the cows saw they were over there they wanted to be over there too and that's how they were getting out. The calves would get out and then the cows would go through, over, under, whatever they had to do to get to their calves. In my opinion there isn't a fence in the world that can hold in a cow that wants to get out. They always find a way. We've got a 30 mile Snapper juicing our fence and when I've had the unfortunate luck of brushing it, when the shock goes out of your foot into the ground, it hurts for a long time. I was pulling wet weeds aways from the hot wire once and it nailed me, it works great. Kind of funny to see the calves sniff it when they are first born. I would bet they can sense the electricity, but don't know what it is.