Miniature tend to be a lot more expensive because so many people don't have much room or are intimidated by size.I didn’t mean just one cow, I actually have experience with cattle. My grandfather raises beef cattle for a living. We are thinking about a miniature Jersey though, any thoughts on that? This is what is available in our area. But I was thinking we will need a pretty hardy one, due to some pretty swampy weather in the summer. Which ones would you recommend?
If I were you, I would ask grandfather to breed a couple of his cows to a milky simmental or old style shorthorn (current milking shorthorn have a lot of holstein in them, and current shorthorn aren't very dual purpose anymore). A few people have been searching out forgotten straws or whatever of bulls from the seventies or so. Those straws are hard to get but sons and grandsons are more available. You have to look for them - they aren't at Select Sires yet that I know of.
My second choice of AI sire would be any of the dairy breeds - whatever has the highest udder attachment score (you will need that crossing with beef), and lowest milk production (avoids a lot of the metabolism problems). I have some bias against Jerseys because they are known for milk fever issues. And for being pocket cows - I like more stand off-ishness in cows.
If you live down south, some of the brahma breeds are pretty milky. I don't know very much about them. Evidentally longhorns can be also.
A lot of family cow people like Dutch Belted; that is a good choice. I would avoid Dexters. Good ones are a good fit but there aren't too many good ones.
If grandpa is willing, pick the cow with the best udder attachments that doesn't also have bottle teats.
If I were me, I would get a cull cow from a dairy - one culled for low production in a low production bloodline but no history of mastitis or breeding back problems. Test for Johannes, at least. Or a holstein/angus or holstein/simmental cross. Actually, I had longhorn in my plan for quite a while - and I'd dehorn or cross with a polled line... because I care about easy, avoid problems...not necessarily what most people value.
There are other good choices, I think, but I don't know much about them, murray grey, for one, maybe. I'd avoid the really rare breeds (like Randalls).