A) Serum progestagens (ng/ml) of the female elephant which was inseminated with frozen semen. Increase and remain of serum progestagens at high level more than 20 weeks after AI indicated pregnancy. Discontinuous lines represent missing data due to blood samples could not be collected. B) Sonogram of elephant conception at day 107 post ovulation. The white arrow indicated embryo with the diameter of 43 mm.