I've never had a problem with it When I fed raw before, my dogs got a lot of freezer burned meat because it was cheap to pick up when people were cleaning out their freezers. Freezer burn is basically just portions of the meat drying out in the freezer. I think it oxidizes the fat a bit too, but it's never made any difference to my dogs' health.
Is freezer burned ground beef less nutritious then normal frozen meat?
It may affect the nutritional value a bit but most likely just a small % of it....I'm not sure if it affects the potassium, sodium, magnesium and calcium but may diminish the vitamin A, B-12, and B-6 present in ground beef.