Effects of preovulatory estradiol on uterine environment and conceptus survival from fertilization to maternal recognition of pregnancy†

Abstract

Preovulatory estradiol is known to impact embryo quality and survival. The objective of this study was to determine the effects of preovulatory estradiol on the uterine environment and conceptus survival through maternal recognition of pregnancy. Beef cows/heifers were AIed following induced ovulation. Cows were grouped into high and low preovulatory estradiol. Conceptuses were collected on day 16 nonsurgically (Rep 1; n = 20), or following slaughter (Rep 2; n = 29). Blood was collected to determine plasma glucose concentrations, and uterine luminal fluid (ULF) was analyzed for protein, glucose, and interferon tau (IFNT) concentrations. Total cellular RNA was extracted from caruncular (CAR) and intercaruncular (INCAR) endometrial tissue. There was no effect of preovulatory estradiol on conceptus recovery rate (P = 0.38) or on apoptosis rate in the trophectoderm (P = 0.64). Cows in which a conceptus was recovered had greater concentrations of protein in the ULF (P = 0.04). Animals with elevated preovulatory estradiol had greater endometrial abundance of SLC2A1 (P = 0.05) and SLC5A1 (P = 0.04) in both INCAR and CAR tissue. Presence of a conceptus also tended to increase (P = 0.10) abundance of SLC5A1 in INCAR. In CAR tissue, cows with a conceptus had decreased SLC2A4 abundance (P = 0.05). In summary, conceptus recovery rates, apoptosis in the trophectoderm, IFNT, glucose, and protein concentration in ULF did not differ between cows that did or did not have an increase in preovulatory estradiol concentrations. Thus, there is no indication of increased conceptus survival to day 16 of pregnancy based on estradiol concentrations.

Stimulation of follicle growth and development during estrus in Ettawa Grade does fed a flushing supplement of different polyunsaturated fatty acids

“…The high estradiol concentration during estrus in the LAURIC group is related to high estrous behavior [44]. A high level of estradiol secretion during estrus at the beginning of the reproductive process has a strong effect in stimulating uterus growth and development to support the uterine environment for fertilization and conceptus development [45,46].…”

Genomic merit for reproductive traits. I: Estrous characteristics and fertility in Holstein heifers

“…Expression of signs of estrus at the end of an ovulation synchronization protocol was associated with expression of genes in the endometrium, corpus luteum, and conceptus 19 d after AI associated with local immune system, adhesion of endometrium epithelial cells and the conceptus, PGF 2α synthesis, and apoptosis (Davoodi et al, 2016). In a recent study, cows with greater concentrations of estradiol around the time of ovulation had upregulation of genes associated with facilitated glucose transport in the caruncular and intercaruncular tissues, which may represent a new pathway through which estradiol modulates uterine environment and pregnancy establishment (Northrop et al, 2018). Genomic merit for HCR was positively associated with pregnancy to second AI and tended to be positively associated with the hazard of pregnancy up to 80 d after enrollment.…”

Effects of FSH treatment and withdrawal during proestrus on uterine proliferation and steroid hormone receptor expression in beef heifers

“…These changes are primarily regulated by E2 and P4 (Spencer et al, 2004), and steroid receptors change throughout the estrous cycle (Robinson et al, 2001). Thus, the uterine environment changes dynamically during the estrous cycle, and this environment plays a vital role in maternal recognition of pregnancy, elongation, and attachment through secretion of nutrients and growth factors that are necessary for optimal embryonic growth and development (Northrop et al, 2018; Patel et al, 2015; Spencer et al, 2004). The E2‐induced expression of endometrial receptors and production of uterine proteins also influenced the expression of many genes involved in uterine extracellular matrix remodeling (Bauersachs et al, 2005).…”