Archer,
As said earlier, I would go to the Farm Service Agency near you and get as much information as possible from them. Hopefully they will be more helpful than mine. I am 22 and got my first time farmers loan this summer. I bought a tractor, hay rake, a disc cutter to harvest hay (already had a baler), 20 bred brangus cows, and a couple thousand dollar operating loan. I think I borrowed about $35,000 total. I got out of this cheap b/c I bought used equipment and my dad already had cows so now I am just a partner with him. He already had the land, fence, buildings, corral, trailer, BULL, and other things. Also if something goes wrong and my cows don't make enough money to make my payment, my dad's calves are there to help me make a payment. Without this it would be really tough for me to make it.
As far as how many cows per acre. We run about 1 cow to an acre. Oh yeh and we have 2 horses on them too. This is with no fertilization and no weed control. Without doing either of those, our pastures were maxed out. We can't put anymore cows on the grass we have. If we would have fertilized and sprayed for weeds this year the cows could not have kept up with the grass. But we do have some of the best pasture in the country. I am in Northeast Arkansas and we run our cows on the levee bordering the Mississippi River. Really good ground and bermuda grass.
I would say get black angus. I bought brangus b/c I really liked the look of these cows. They had the bigger structure of the brahma but the good looks of the angus. Not alot of ear. Get a good bull with good EPDs. Talk to as many people as you can about raising cattle. (this is a good place to start) You pick up a lot of stuff by just being around people that raise cattle, so meet as many people in your area as possible. From personal experience, I wouldn't buy your breeding stock from a salebarn.
When you figure how much each cow will cost, use a high end figure and when figuring how much you will make from their calves use a really low price that way you have more than enough to make your payments.
I would bet on your bred cows costing you about $1000 a piece. The guy I bought mine from gave them to me for $950 /hd because I was a getting into the business. The rest he sold on superior livestock for about $1125 /hd. I don't know how many head you could support a family of 5 on. I would guess it would have to be really high. I like to have nice things so I would say a atleast 300 to 500? Or more? I don't know. It takes alot of head to make money if you are paying for land, equipment, etc....
If you try to get a loan from the FSA, you will have to be denied credit by 2 banks first. So if you can get a loan somewhere else I would just go to the FSA to get all the budget and cost information.
And Last but not least, even though you make think X amount is plenty of money to run your business go ahead and ask for more just in case. If you don't have to use it then just pay it back on the end of the loan. That is one piece of advice that I was given but didn't follow. I wish I would have.
I don't know near as much as most all these people on this board, but that is my viewpoint as a beginner. If you have anymore questions just let me know and I will try to help out as much as possible.
Josh