When a dairy cow gives birth her calf is taken away from her and is not allowed to suckle after the first day or two after birth. This is because it is quite difficult to match up a cow to her calf after she is taken away from milking, and even more of a headache to have a bunch of loose baby calves around. Milk also has to be allocated so that the calf is getting a fair amount while at the same time milk can be taken from the cow to be sold and used by humans. Thus, it is much easier to remove the calf a day or two after birth (after it has had its few suckles of colostrum), and put the cows into milk production almost right away. Most dairies have their cows milked twice a day for around 10 months. She is then allowed to rest (i.e., dry up or not be milked at all) for two months prior to giving birth to her next calf. Majority of dairy cows are kept in barns or sheds throughout their lives, occasionally going out to pasture to graze, though for some farms this is even unheard-of.
A beef cow is raised more "naturally" than a dairy cow: she often has never seen the inside of a barn before, and is out seeking her own food source (grass) and raising a calf at her side for 6 to 10 months. She's allowed to roam wherever the fences allower her to go (and restrict her from where she shouldn't), and raise her calf as she sees fit. Beef cattle are raised for the purpose of producing meat, not milk, so the cow produces only enough milk for her one calf to thrive on and grow "soggy" on, not for human consumption.
Dairy
That all depends on the breed. Are you asking about a dairy cow or a beef cow, and what breed of dairy or beef cow?
Nothing wrong with that. Dairy cows are slaughtered for beef as culls anyway, so it's no big deal if you slaughter a dairy cow and turn her into ground beef.
No. The biggest type of bovine is typically the beef cow. There are beef cows around that weight more than a big dairy cow, and that can be upwards of 2000 lbs or more.
Yes.
All of the same cuts you could from a beef cow, just not as much muscular volume.
No. She is a dairy cow, one that is used to primarily produce milk.
Beef and Dairy products.
For beef and dairy cows, lactation period begins immediately after a calf is born. For beef cows, the lactation period ends when their calves are weaned off of them. For a dairy cow, the lactation period ends when she is not longer being milked and allowed to dry up so that she can focus on putting energy into growing the calf inside her. The dry period for a dairy cow is shorter than a beef cow's: two months for a dairy cow, and four to five months for a beef cow.
Yes, they have a high quality meat.
A dairy cow would die a matter of a few weeks before she even gets to the point where she is deemed "feral." I would see a beef cow becoming feral, yes, but not a dairy cow.
Only if she's a dairy cow, like a Holstein or Jersey or some sort of dairy cross, like Holsetin-Jersey cross or Swiss-Jersey or Swiss-Holstein cross. Those type of cows can nurse up to four calves at once, with one calf on each tit. A beef cow or beef-dairy cross cow will not be able to feed three calves at once, only one; dairy-beef cross cows may be able to get away with feeding two at the most; occasionally three if she's a high-producing cow for a beef-dairy cross.