Doctor of Philosophy (PhD)


Veterinary Clinical Sciences

Document Type



Changes to the embryonic environment that occur within the first few days of development can have significant effects on subsequent fetal development. The following studies investigate the effects of progesterone-deprivation during the early preimplantation period in the mare. The first study described embryo morphology (diameter, stage, and quality grade) collected from mares with induced aluteal cycles. The second study evaluated the effect of induced aluteal cycles on the future fertility of embryo collections as a potential method for cycle manipulation of embryo donor mares. The third study characterized embryonic and endometrial transcript expression of progesterone-mediated transcripts as well as those related to normal embryo growth and pregnancy establishment during induced aluteal cycles. Finally, the fourth study evaluated the potential for the successful establishment of pregnancy when preimplantation embryos were deprived of progesterone. Embryos developed in a progesterone-deprived environment were developmentally delayed by all parameters evaluated. A significant effect was seen on the transcript expression of embryos and endometrium collected from progesterone-deprived cycles in the mare. Embryos deprived of progesterone during the early preimplantation period demonstrated delayed embryonic vesicle growth compared to control cycles. No effect was seen on the future fertility of embryo collections after utilizing progesterone-deprived cycles. The results of these studies elucidate the significance of adequate progesterone levels beginning immediately post-ovulation in the mare.



Committee Chair

Paccamonti, Dale