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. Maybe you mean a water buffalo?

Lactose is present in all mammal milks to some degree and thus lactase persistence can have some benefits regardless of the specific animal the milk comes from.

Goats milk aminoprofile is closer to human milk. Cows milk is 90/10 casein/wheyprotein, goats milk is 60/40 or 40/60 IIRC.