The ox (소, so) is read about as favorably as any animal in this tradition, for a very practical historical reason: in an agrarian society, an ox wasn't just valuable, it was the literal engine of a family's livelihood, pulling the plow that made everything else possible.
An ox pulling a cart or plow steadily is read as fortune arriving through honest, sustained effort rather than a sudden windfall — a notably different flavor of good news than a pig or money dream, closer to "the work is paying off" than "something landed in your lap."
A large, healthy, well-fed ox is read as substantial wealth, while riding an ox calmly is read as smooth, dignified progress — an image that echoes similar ox-riding imagery found across East Asian art and Zen tradition more broadly, generally symbolizing a settled mastery over one's own path.
An ox giving birth to a calf is read as wealth multiplying, in the same family as a pig's litter or a piglet giving birth. A wild, fighting, or uncontrollable ox flips the reading toward obstacles — often specifically a stubborn person, or your own stubbornness, blocking otherwise steady progress.