artificial fertilization
2.Protein was to planed to three levels -low (80%NRC), moderate(100%NRC) and high (120%NRC) . 100 small-fat-tail sheep was selected to make to have the same oestrus and be mated by artificial fertilization.
3.Equally important, women who are single could have a child using cloning instead of in-vitro fertilization or artificial insemination.

