Mostly it is genetics. It is important to understand fiber growth to help you make good breeding choices for each fiber type. In Australia they are making leaps and bounds in recovering from their disastrous sheep breeding programs, quantity over quality. The alpaca world should keep a close eye on their industry and learn from their mistakes and successes. Just recently the news of an ultra fine merino fleece braking the twelve micron barrier with a micron count of 11.9 was huge news for the natural fiber industry!