Too add what Ashley mentioned, you need a larger land base plus more feed to feed one cow than one goat. You can feed 1/4 of the feed needed for a cow to a single goat--maybe closer to 1/3 for a miniature bovine, and just as much less land is required for one goat. You can also have one acre of land for a herd of around 4 or 5 goats where you can only have one cow at the most--even two mini's may be stretching your resources--for that single acre. As far as expenses are concerned, a cow is more expensive to feed--a cow tends to eat a lot (she'll eat more lactating than when dry) and cows are lactating for most of the year anyway--than a goat not just because she has a higher consumption rate as I've mentioned twice already, but nutritional demands are such that you may need to invest in purchasing feed--as in feed grain, protein or mineral supplements--moreso than you initially considered. And as mentioned before (I can't stress this enough), an entire bag of feed for one cow would be for that one cow for maybe a couple of weeks, whereas that one bag can last for over a month for just one goat (as an estimate; it could last longer, depending on the weight of the goats and how much they eat per day).
I concur that miniature cattle are far more expensive upon purchase (let's not take into account the costs of keeping her, as that's a different story) than a small herd of goats. Cost of keeping that one cow is expensive as well. And it's not worth keeping a bull because he'll eat up more of your money than you think, not to mention bulls can be hard on fences, hard to handle and hard on you. They're not fun when they get ornery and rouge.
All of us cow people on here agree that if you only have one or two acres of land to work with, you're best option is buying a herd of goats instead of a cow or two.
