um not really plausable if you ask me. Brands are typically just a series of letters and numbers, or symbols. And on the neck, not inside the ear. Its not really painful. Its the same as if you went and got a wart removed by freezing it. Same thing. Just a little pinch. All our horses are freezebranded now. They used to have the inside of the upper lip tattooed. But this is a better method.
But the tanks that hold the dry ice to do this only have a small opening, so really you're not going to be able to put this big huge brand in it.