Beef

An English slang and informal name simply referring to beef — the meat itself — used humorously as a pet name, playing on the dog's size, strength, or the owner's sense of humor.

Beef is the name that gets given in a moment of absolute inspiration, usually right after meeting a large, meaty, muscular dog who is clearly too much dog for an ordinary name. It is honest, it is funny, and it works completely. Dogs named Beef tend to be big-bodied and soft-hearted, all that muscle wrapped around a genuinely gentle soul. He probably thinks he is a lap dog. He is not entirely wrong.