No, cows continue to lactate after giving birth (between pregnancies).
Many cows are 'dried off' (where they stop lactating) during the later stage of pregnancy before she gives birth again.
Nothing, really, except cow's milk comes from lactating cows and human milk comes from lactating women.
Typically a lactating cow will eat 50% more than a dry cow would. As for energy needs, a lactating cow needs around 15% more energy than dry cows do.
Springer cows are cows that are just starting to produce milk. Regular cows can be any cow, be they pregnant, lactating, or open (not pregnant).
A cow typically needs 7% (non-lactating cows) to 10% (lactating) of her body weight in water per day.
If you are referring to when a cow starts to lactate, it's called freshening.
A bred cow or a pregnant cow, or, in the dairy industry, just a cow. In sale barns, if she has a calf at side, she is also referred to as a 3-in-1 or a three-fer or suckling bred cow. If she's lactating, like in a beef or dairy herd, then she's called a nursing bred cow, lactating bred cow or bred lactating/milking dairy cow. If she's not nursing or lactating, she's called a dry bred cow non-lactating pregnant cow if you really want to get technical. In the dairy industry, a lactating heifer that has already had her first calf is referred to as a first-calf heifer; once she has a second calf she is generally referred to as a cow. In the beef industry, a heifer that is pregnant with her first calf is called a bred heifer.
Estrogen does not cause a lactating cow to be lame. Feed that is high in energy and protein (like grain) can cause a cow to founder (or be lame). Injury is also a likely cause for a cow to become lame; a cut that has invited infection will also cause a cow to become lame. But not estrogen.
Only one.
None, unless that cow is showing some sign if illness. Don't treat the symptoms, treat the actual disease.
A typical cow will be lactating for 6 to 10 months.
A wet cow, if you're referring to a cow that's been out in the rain. However, it would have a different meaning. For some, a "wet" cow can refer to a cow that is giving milk or lactating, which is opposite of being a "dry" cow. Dry cows are those that are not giving milk.
If she's lactating and you have no foster calves for her to nurse, yes. If not, then no. If you have two or three calves for her to nurse, then no.