So you have a lovely herdsire stud, and a beautiful dam, and your ready to breed them and get a wonderfully cute and cuddly cria! There are two basic ways you can get the female impregnated, putting the herdsire and dam into a pen, or a paddock. Which way you decide to go with will depend on your alpacas personality. First start out with a pen, if you notice either the male or female pacing along the pen as if they want to get out it either means they cannot focus on breeding in the pen, or the female is not ready and/or the male is to immature to breed.
To tell if your female has gotten pregnant, the simple way is to put her in a pen/paddock with the male again and if she spits at him then she is saying, im already pregnant, back off. Or you could get an external ultrasound which would be done by your vet.
Once you know your female is pregnant, all you can do it sit and wait and let nature take its course over the next 11 and a half months. Make sure to watch your female though, provide her with high quality feed, lots of protein and hay so you can make sure that the cria inside is healthy too.
I have not had experience with the birth of a cria, and I dont think watching a alpacas/llamas relative (forgot the name) give birth in the wild on animal planet counts. I do have experience with sheep giving birth and I know that there are the certain times where things can go wrong, I have lost Ewes and there babies because of difficulties. From experience with sheep, I recommend calling the vet and telling them what is going wrong and or happening, and go from there.
If you have a personal experience with birthing of a cria that has resulted good or bad. I would love to hear it and put it on the website/blog for others to read about it to get a more personal story other than reading facts and what do to step by step on a website. Please contact me for more information.