Timing of transcriptomic and proteomic changes in the bovine placentome after parturition.

Proper post-partum reproductive performance is important for reproductive efficiency in beef cows, and dystocia decreases post-partum fertility. Crossbred beef cows (n = 1676) were evaluated for lifetime performance based on degree of dystocia at presentation of the first calf. Cows that experienced moderate or severe dystocia produced fewer calves during their productive life (P < 0.

Beef heifers with diminished numbers of antral follicles have decreased uterine protein concentrations.

Previous research demonstrated a favorable relationship between the number of follicles detectable in the bovine ovary by ultrasonography and fertility, and bovine females with diminished numbers of antral follicles had smaller reproductive tracts. Therefore, we hypothesized that uterine function would be compromised in beef heifers with diminished numbers of antral follilcles. Angus heifers (n=480) were submitted for ultrasonographic evaluation of antral follicle number at 325 and 355d of age.

Influence of post-insemination nutrition on embryonic development in beef heifers.

Previous studies have demonstrated that a decrease in nutrition immediately following AI reduces pregnancy success in beef heifers. The objective of this experiment was to determine if nutrient restriction following AI impacted early embryonic development among non-super ovulated heifers. Beef heifers in eight replications (Rep; Rep 1; n = 14, Rep 2; n = 15, Rep 3; n = 15, Rep 4; n = 14, Rep 5; n = 15, Rep 6; n = 15, Rep 7; n = 25, Rep 8; n = 25) across two locations (UMN, SDSU) were developed in a dry-lot and fed 125% NRC requirements from weaning to timed-AI (d 0).

Uterine environment and pregnancy rate of heifers with elevated plasma urea nitrogen.

Diets high in protein are associated with lower reproductive performance and changes in the uterine environment. The objective of this study was to determine the effect of elevated systemic concentrations of urea nitrogen on the uterine environment and pregnancy success in beef heifers. Heifers (n=150) were matched by breed, age, and body weight then randomly assigned to one of two dietary treatments: 1) Control (10% CP) or 2) High protein (14% CP) over three replicates (n=40/replicate).

Changes in ovarian function associated with circulating concentrations of estradiol before a GnRH-induced ovulation in beef cows.

These studies were conducted to evaluate causes for differences in circulating concentrations of estradiol before a GnRH-induced ovulation. Beef cows were synchronized by an injection of GnRH on day -7 and an injection of prostaglandin F2α (PGF2α) on day 0. In experiment 1, blood samples were collected every 3 h from PGF2α on day 0 to hour 33 after PGF2α and at slaughter (hour 36 to 42; n = 10).