Wash the meat and place in a large soup pot. Add the garlic, tomatoes, salt, pepper, and 3 quarts water. Bring to a boil over high heat. Skim the scum that accumulates on top; lower heat to maintain a simmer, and cook, partially covered, for one hour.
Remove the partially cooked meat to a bowl while you strain the stock and separate about 1½ quarts. This will be the soup you will be serving. Return the remaining stock and the meat to the pot (there should be just enough stock to just cover the meat. If not, add some of the reserved stock). Simmer, covered, until the meat is tender. (Note: My mother always did this because she liked the pure, intense flavor of the stock. I do it this way, too, but have skipped this step on occasion, and the soup was still delicious. It’s up to you.)
Meanwhile, parboil all the vegetables separately in mildly salted water. They should be crisp-tender.
To serve, heat reserved stock with the cilantro sprigs to a boil and cook for 5 minutes. Add vegetables and cook just until heated through. Serve with fresh Pico de Gallo Norteño or another table sauce.