I would say 4 years !

puberty by 2-3 years

mating by 4th year

give first birth by 5th year

Thank you. This is what happen in dromedaries (With a bit of luck! With a lot of luck even 4.5 years). Bactrians seems more precocious breeders (at least males) so I was wondering if perhaps a % of Bactrain females can deliver at 3 years. 

I don't know about camels, but I have seen in goats that what frequently happens when underdeveloped females get offspring is that the females become too lean and even stop growing (they might in some cases never reach a normal adult weight), they can't provide the offspring with enough milk, and both the female and her offspring end up in bad condition and underdeveloped. So even if it is possible for them to get pregnant early, it might be biologically and economically unsuitable.

I don't know if the same is valid for camels as for goats, but I would guess there is such a risk. If you give them another year, you might end up with better results and better total economy.

Hi, I agree with you, female can be reproduced so early, but we should differentiate between age of puberty and age of full maturity to avoid such complications in growth rate and at time of parturition (dystocia). 

Hi Malin I agree with you and with Ahmed. Under pastoral conditions early breeding (mating at around 4 years) while regularly occurring is still not widespread since nomads allow it only if the heifer is properly grown and in good body condition. Would be interesting to know what is the earliest breeding age on the Australian feral dromedaries. Understanding what is the best camel breeding practice is not easy because of numerous issues carefully evaluated by the camel breeders: breed size (female adult bw can vary in various breeds from 350 kg to 600 plus kg) and the various "attitudes" within the breed that have to be balanced in the family herd (frequent breeder with poor but long lactation, frequent breeder with good but short lactation, slow breeder with poor and short lactation but drought/tryp resistant and capable to tolerate long watering intervals, slow breeder with poor short lactation but with easy milk let down ETC ETC !)