We've got sheep and goats on our lease, and they're worse than cows any day. What we've done is run goat wire fences around the feeders with one strand of barbed wire around the top. The barbed wire isn't more than 4-6" higher than the goat wire. It is a pain, since the ground is so rocky, and nigh impossible to drive T-posts, and the 'pens' have to be big enough to not make the deer feel like they're jumping into a cage, but it works. The goat wire is low enough to encourage the deer to come in, but high enough to keep the goats and (5) cows out.
This is what most of our feeders look like:
http://www.allseasonsfeeders.com/shop/p ... ucts_id=25
The 'coon solution is a bit messier. they still try to climb the legs, even with PVC sleeves on them that are supposed to make them fall off. To stop that bad behavior, slather the pipe with Vaseline to keep the critters from getting any purchase with their feet. It usually works pretty well.
The All-Seasons feeders do have provisions for staking the legs to the ground, but that doesn't really help if the cows try to push them over.