Since you are no longer supposed to use Ipecac to induce vomiting in humans that may be a use for it. I'm not sure if it works on aminals the same way it works on humans though.

I would be concerned that it would not have the same effect on the deer (ie either no effect, or a dead deer)

You need a pretty good-sized dose to achieve that effect in people; I doubt you'd be able to get enough down a deer's gullet to cause much effect at all.

Do deer have the ability to vomit? Horses don't.