Not quite; they have to give birth to a calf in order to lactate.
No. Cows can be open and still be able to lactate. They must have GIVEN BIRTH to a calf in order to be able to lactate.
No.
No, not usually.
Yes.
No. Heifers, being young female cattle, don't lactate until after they've had their first calf, which is typically at 24 months of age. A heifer remains a heifer, from birth, until she's had her first or second calf, whereby she is considered a cow. But until then, heifers don't lactate like cows do, and when they do lactate after birthing a calf, they typically produce less milk than their older counterparts.
it is called serving
Because people milk them. Same stimulation as if a calf was sucking the teat.
Yes they do because all cows are girls and all bulls are boys
Cows can breed for as long as they are productive, which can range from one to 15 years or more.
No ... cows can't survive underwater, and the octopus can't graze on land ...
if they didnt they would be extinct by now
No, cows must be delivered of a calf in order to lactate, or produce milk. Most large dairy farms will remove the calf from the cow right after birth and give it milk replacer, and this will allow the cow to be milked to maximum.