I ride through it on pretty much every MTB ride as its on my way to the woods. The cows are fine and are used to MTB’s so mainly stay out of the way. There’s dogs and walkers everywhere though, usually trying to climb a rock garden as you’re coming down.
Some parts have been closed for a couple of years and others are really overgrown. The parts that are open have very loose gravel, not the best place for inexperienced riders unless you stick to the shared green route. I live close and only ride it in the winter when I have to.