Plasma progesterone profiles and embryo quality in superovulated Japanese Black cattle

The relationship between plasma progesterone (P(4)) levels before and after superovulation treatment and embryo yield and quality was examined in Japanese Black cattle. It is concluded that a plasma P(4) level at the start of follicle stimulating hormone (FSH) injections is related to embryo quality. The P(4) level of over 3.0 ng/ml appears to be useful in preselection of donors when we want to get more than 8 normal (transferable) embryos on the average.