That all depends on what you mean by "bad milk." "Bad milk" can mean anything from milk that tastes bad or is infected with mastitis, or even a cow that is not producing much milk in the first place. So pick one and please re-ask the question again so you can get a more specific answer.
No.
When the cow has just had a calf or is suckling a calf.
you have to have a calf in order to milk a cow
Calf milk poweder is for baby cows that, for some reason, can not nurse from there mother. Calf milk powder is the same to a cow as formula is to an infant.
When she gives birth to a calf.
Yes.
A cow nurses it's babies much the same as a human. she has an utter, filled with milk that the calf sucks on to get milk. A cow nurses it's babies much the same as a human. she has an utter, filled with milk that the calf sucks on to get milk.
I saw a baby calf drinking the milk of her mother cow.
It depends. Is she a beef cow or dairy cow? Are you wanting to keep the cow with the calf or separating the calf from the cow? Usually with beef cows you don't bother with milking them unless you have to because the calf isn't up and suckling soon after birth and you want to encourage the calf to be up and suckling, or to get some milk from a cow or heifer that won't accept her calf right away to feed that calf with. With dairy cows, though, if you've separated the calf from the cow right away, it's ideal to milk that cow to collect the colostrum to feed that calf--and other calves--to the benefit of the calf's health. But, if you are wanting to keep the calf with the cow for a couple of days, then no, it's not necessary.
Yes, but it depends on several factors. For information please see the related link below.
Yes.
by drinking mama milk from the female cow .