Beef or pork trotters?

I think they have more cartilage than fat. There's the skin, but I don't really think of that as fat. I want beef feet for making stock. I do eat the pig's feet, but I boil them first. Depending on how much you boil them, they can be tough and chewy or completely falling apart. If they're falling apart, it's easy to remove the bones, and you can pick at the meat more easily. You can fry or confit them afterwards to get them to crisp up, and then you won't have any mushy fat. Pig's feet also make a great broth; I save it and use it to make sauce for my pork chops.