not gonna have much luck pulling a plow with a dairy or beef cow. get a couple of equal bull calves and steer them young so they will become oxen. then before they get big break them to yoke. probably going to need all 5 acres for your cow and then plan on winter feed also. a good jersey cow should be able to provide for your family and a few pigs and chickens. remember to get one with four good quarters and decent tits. or get a dairy goat. an alpine makes mild milk and they don't climb or bawl all the time.