A cow is born with nipples--or rather, teats--therefore this question is impossible to answer. However, if you are asking about the formation of an udder being an indicator to when a cow will give birth, it could be anywhere from days to several weeks.
--milk them
About 12 hours..if your a man
For the vagina about a week nipples until she done nursing, after nursing it will take 10 to 14 days till all milk is dried up
a long time
An average of 42 days is the time is takes for a ferret to give birth.
It takes 12 months for a dolphin to give birth to another dolphin (calf).
Mollies typically give birth within 4 to 6 weeks after mating.
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The time it takes for Molly to give birth can vary, but on average it can take around 6 to 12 hours for a dog to give birth to a litter of puppies.
It takes around 3 - 4 weeks for a platy fish to give birth.
just over a year
I think six weeks