Always glad to hear that somebody wants to milk a cow! So congrats.
Having seen pics of your pastures, and with the
thread title, it sounds like you realize that you dont exactly have 'dairy quality' pastures. Do you plant to supplement with alfalfa
hay to get a good diet for the cow? I would say that this is imperative, to balance out your pasture nutrition.
If you
feed a diet of fair quality rotated pasture, with a daily supplement of 10-15 pounds alfalfa hay, milking once a day, I think you would be good. Dont feed grain, it is not an
answer, it is a problem in and of itself.
As for breed, I would avoid Jerseys and Holsteins. Jerseys give too much butterfat for the amount of body condition they carry. Unless their feeding is prefect, they will likely have health and or fertility problems. Holsteins just give lousy milk.
I would recommend talking to your milk source down valley about one of their Brown Swiss. Get a modest producer, with excellent health history. Get a cow, not a heifer. Their animals are more rugged than most dairy cows nowadays. A big, bad ass Brown Swiss will be able to handle rough conditions quite easily.
Feel free to PM me for any other questions you might have, I am glad to help.
good luck!