I've only had nigis going on 2 years, BUT all the breeders I've spoken with here breed around 8 months. I did have two last year that were bred accidentally at 5 months and each had easy birthings. I personally am going to go by size of the goat more so than age. But my babies from March of this year are about 2/3rds the size as some of my smaller does, so if by December they are looking good, I am going to breed them. I've heard that it is better as far as milk production for the goat to be bred around 8 months, but I don't have a lot of personal experience to back that up. The two that were bred at 5 months (which was my fault completely and won't happen again!) did extremely well. Their body condition is very good, they were EXCELLENT moms and birthed alone without any assistance from me at all. They also are doing very well for me in the milk pail. I was going to hold them off for a year when they first birthed because of concerns they would be small, but they're looking as good as my older dams, so I am still thinking about if I will breed them this fall or not. I have a goat addiction, you see, and in my mind the more goats the merrier, but I really have to think about how many I need to have in milk too!