Concentrations of progesterone prior to luteolysis modulates the uterine luminal transcriptome in the subsequent cycle in cattle

Sex-steroids concentrations throughout the estrous cycle modulate endometrial function and fertility in cattle. The objective of this study was to compare the post-estrus endometrial transcriptome of cows that were exposed to contrasting pre-estrus concentrations of progesterone before they displayed estrus and ovulated spontaneously. We hypothesized that greater pre-estrus concentration of progesterone alters post-estrus endometrial function even after the display of estrus and spontaneous ovulation. Bos indicus-influenced cross-bred beef cows exposed to either high (H) or low (L) pre-estrus concentrations of progesterone. On day -9, the cows assigned to the high progesterone treatment received a new CIDR and 2 mL GnRH i.m. while the cows assigned to low progesterone treatment received a CIDR used twice previously, 5 mL PGF2α i.m. and 2 mL GnRH i.m. Ovarian ultrasonography and blood collections were performed on d -9, d -2, d -0.5, d 0 (observed estrus), d 4, d 7, and d 14 for measurement of ovarian structures, progesterone, and estradiol. Luminal epithelial cells were collected using a cytology brush on d 4, d 7, and d 14 for RNA-sequencing analysis.