It depends on whether one plans to stay i n that place and make a home there, or move on. Also, a cow produces milk only when she calves/ is being pregnant/has a calf, and every pregnancy sooner or later comes to a natural end. Or to be preicse: a cow produces milk for the calf she has, even during the follow-on pregnancy. No calf - no milk anymore .
Finally it depends on whether you are a vegan, a vegetarian, or a monster.
