You might be thinking of a different animal. An ox isn't a good choice as an milking animal, as it typically is a castrated male bovine. If female, it would a

You might be thinking of a different animal. An ox isn't a good choice as an milking animal, as it typically is a castrated male bovine. If female, it would at least produce milk, but then it would just be a cow used for plowing, and would have the same milk as a dairy cow: https://en.wikipedia.org/wiki/Ox https://en.wikipedia.org/wiki/Ox. Maybe you mean a water buffalo?