Our horses have eaten all the bark off most of the tree. It is a fruitless variety mulberry. . . very established. What can be done to make sure the tree doesn't die?
Saving a Fruitless Mulberry Tree
This article may help: https://www.gardeningknowhow.com/ornamental/trees/tgen/repairing-tree-bark-damage.htm
Hopefully your tree was not girdled all the way around the trunk, it if was, you have enough bark left to try some of the reattachment methods listed in the article.