I will be getting 2 Nubian alpine crosses on is 2 years old and then the other is her four month old kid I was wondering these does are for milk and when will they next need to be breed?
Just a quick note about kidding. Please anyone feel free to correct me if I am wrong but typically most people breed their yearling does when and if they have reached about half their adult weight which is around 80 pounds. Like Kstaven said a goats pregnancy lasts around 150 days. Also, the breeding season for nubian/alpine probably is similiar to seasonal breeders. Thus being you breed in the fall (September onward) through December- January. I have heard that you can breed seasonal goats during any month with an r in it's name..
Breeding at a year is too old, you want them to be bred at 7-8 months and at 75lbs or more. That would put them to kid at 12 months, when they should kid for dairy breeds. The longer you wait to breed then the less productive they will be. They will also put on more fat if they are bred later on and that can lead to reproductive problems.
Dairy breeds of goats are seasonal breeders, cycling from fall to winter, where I live in California they cycle from August to February.
Gestation is 150 days on average, they can be -5 or +5 days from 150 days.
The doe kid that is 4 months old now should be breed-able by this fall as long as she us at least 75 pounds, if you breed any smaller than that size you risk stunted growth for life.
You can breed the doe this fall as well, or you can induce heat and ovulation and breed her now, for Halloween kids.
Does are normally kept in milk for 10 months and dried up for the next kid. However you don't need to keep them in lactation that long. I kid in January and February, milk until September, breed them, and keep milking until November then dry them up, kid in jan-feb and do it all over again. That way they are dry for about 3 months before they kid, put some body condition on for the next go round.
Hopefully I answered all the questions you have currently.