Oh wow, that's a lot of damage. Don't apply anything to the wound i'd say, might be better to heal over on it's own but I would try put a roll of netting or such around it to prevent the deer from finishing it off.
The only thing to do now is wait and see.. I had a moose eat my apple tree such as that..it survived but isn't very lovely looking around the base. The bark is badly scarred.
Hoping someone else can help provide some info as well. They might have info on a spray you could use to repel the animals..