I wonder, normally most people take their meat out of the freezer the day before they give it to their dogs. Maybe its some kind of grass seed that the cows eaten, and because it was in my fridge for a few days it had time to grow. Anyway it sounds common as other people recognise it, think i'll steer clear of it though, or at least make sure i have freezer space for beef. Trying to decide now whether to get a freezer for my dogs or perhaps try and see what local butchers can offer me. Always have a problem being in on the date that daf can deliver anyway and have no safe place for it to be left. Dogs have been on raw for 3 months now and looking good so far.

When I was a child in the early 60s my mother and all her friends had ox cheek ,which they cooked,from the butcher for their dogs.
The spiny white things you describe are a natural part of the ox cheek -we fed this at least twice a week to our dogs and they thrived!