Horses tripping bark off trees?

[whymewhyme]

Just spent half hour poo picking and I noticed that a few are the trees are stripped (picture below) I also have a horrible feeling the tree in the picture is a bloody sycamore! Anybody know why they could be doing this?

If it sycamore at least they are likely to kill it doing that. Don't think eating the bark is going to cause AM though. Are they short on grazing?

When mine start chewing bark it is usually when grass gets lower, they do like some roughage to break things up anyway though, mine are eating all the willow buds they can reach at the moment. I sometimes in winter leave a branch in the field and they strip it of bark completely and chew it also. I don't know about the scymore bark as we are generally ash and willow.

I think sycamores are a type of acer and thus related to maple, so tend to have a sweet bark. My ex’s horses (on excellent grazing and well fed) managed to kill one with their bark stripping.

I've googled it and the bark isn't poisonous, thank god! I am very low on grazing, I'm haying in the field.