Concentrations of Progesterone Alter the Odds of Retention of Transferred Bovine Embryos

Two studies were conducted to examine the role of progesterone on the odds of survival of embryos transferred into lactating and non - lactating recipient cows. In each study, recipients were synchronized for estrus following the Select Synch + CIDR ® protocol. O n d 7, after exhibiting estrus, embryos were inserted in all cows bearing a viable corpus luteum; embryos were placed in the uterine horn of the ovulating side. Randomly, animals were divided into two groups. Contrary with the control group, cows in the CI DR - group had a CIDR inserted on that same day the embryo was inserted and removed 14 days later. Blood samples for analysis of progesterone were taken at insertion (d 7) and continued at 7 - day intervals for three more weeks. All animals were weighed and bo dy condition scored at the beginning of the studies. Pregnancy diagnosis was performed around d 90. No significant differences were observed in body weights between treatments. Progesterone between treatments within days and between days within treatments are reported. Progesterone between pregnant and non - pregnant cattle was also reported between treatments and within treatments. Progesterone seems to increase the odds of retention of transferred bovine embryos during early gestation. Results also seem to point out that patterns of progesterone secretion during the first two weeks after the transfer have a decisive effect on the survival of bovine embryos. Nevertheless, authors of this document suggest that more research is needed to closely examine these f indings.