Local and Systemic Actions of GnRH Relating to Estradiol and Associated Reproductive Parameters in Beef Cattle

In cattle, estradiol is responsible for modulating many mechanisms involved in successful reproduction. Specifically estradiol is the primary signal for the initiation of standing estrus (Allrich, 1994), and cattle expressing estrus prior to fixed time AI (FTAI) have been reported to have increased preovulatory estradiol concentrations (Perry and Perry, 2008) and increased pregnancy success compared to animals that did not exhibit estrus (Richardson et al., 2016). Gonadotropin releasing hormone, classically, stimulates estradiol production via the two-cell two-gonadotropin hypothesis (Fortune and Quirk, 1988), and GnRH administered systemically in small doses (5 μg) has been reported to elicit an LH pulse similar to a physiological pulse (Ginther et al., 1996). In a study where multiple small doses (5 μg) of GnRH were administered following CIDR removal, concentrations of estradiol were increased (Larimore et al., 2016). These studies demonstrate that estradiol production from ovarian follicles could be stimulated with systemically administered GnRH. In addition, to the classical pathway, GnRH receptor mRNA has been characterized in bovine granulosa cells (Ramakrishnappa et al., 2003), and GnRH has been reported to have local stimulatory and inhibitory actions on steroidogenesis within the ovary (Sharpe, 1982; Janssens et al., 2000). The role of GnRH in bovine follicles as it pertains to estradiol production and/or the regulation of estradiol production has not been well characterized. Therefore, the objective of the subsequent studies were to investigate the relationship of GnRH and its impact on estradiol production and other reproductive parameters by conducting field trials where GnRH was administered systemically (Chapters 3 and 4), as well as the local abundance of GnRH-I and GnRH-II mRNA within granulosa cells of bovine antral follicles (Chapter 5). In Chapter 3, beef cows and heifers (n = 1620) were synchronized using the 7-day CIDR protocol, and randomly assigned to one of three treatments (0, 5, and 10 μg of a GnRH analog at CIDR removal). Animals were visually observed for estrus and inseminated following detection in estrus. Interval to estrus was calculated for each animal that exhibited estrus (INTERVAL 1). Animals that did not exhibit estrus were given 100 μg of GnRH at the time of AI and their interval to estrus was designated at 120 h (INTERVAL 2). There was an effect of age (P \u3c 0.01) and a treatment by age interaction (P = 0.05) on INTERVAL 1. Heifers had a shorter interval to estrus than cows (50 h vs 54 h respectively). Furthermore, heifers given 5 μg of GnRH tended to have a shorter interval to estrus (P = 0.07; 47 ± 1.4 h) compared to 0 μg (50 ± 1.5 h) and did have a shorter interval compared to 10 μg (P \u3c 0.01; 52 ± 1.5 h). There were no differences among treatments in interval to estrus among cows (P ≥ 0.34). When animals that did not exhibit estrus were included in the analysis at 120 h there was no treatment by age interaction (P = 0.49). This is likely due to the fact that treatment (P \u3c 0.01), but not age (P = 0.96) or treatment by age (P = 0.74) influenced expression of estrus, with 5 μg tending to have more animals in estrus (P = 0.10; 79 ± 4%) compared to 0 μg (74 ± 5%), and 10 μg having fewer animals in estrus compared to either other treatment (P \u3c 0.04; 68 ± 6%). Estrus (P \u3c 0.01) and age (P \u3c 0.01) influenced pregnancy success with heifers having greater pregnancy success compared to cows (49 ± 5% vs 38 ± 4%, respectively) and animals exhibiting estrus having greater pregnancy success compared to animals that did not exhibit estrus (57 ± 4% vs 32 ± 4%, respectively). However, there was no difference in pregnancy success between treatments among animals that exhibited estrus (P \u3e 0.30). Among animals that did not exhibit estrus 0 μg had increased pregnancy success (P ≤ 0.05; 40 ± 6%) compared to 5 μg and 10 μg which did not differ (27 ± 6% and 29 ± 5%, respectively). This experiment demonstrated that small doses of GnRH following CIDR removal can shorten the interval to estrus and increases the percentage of animals exhibiting estrus prior to AI. In Chapter 4, beef cows and heifers (n = 247) were synchronized using the 7-day CO-Synch + CIDR protocol and were assigned to one of three treatment groups [0 μg GnRH at CIDR removal (0 μg); 10 μg GnRH at CIDR removal (10 μg), or 5 μg at CIDR removal plus 5 μg 12 h later (5 + 5 μg)]. Animals were visually observed for estrus and artificially inseminated 55 (heifers) or 60 (cows) hours following CIDR removal (FTAI). Blood samples were collected beginning at CIDR removal and every 12 hours until time of AI. Concentrations of estradiol were not influenced by treatment (P = 0.66) or a treatment by time interaction (P = 0.87), but were influenced by time (P \u3c 0.0001). Estradiol concentrations increased from CIDR removal to 48 hours after CIDR removal and then were decreased at the time of AI. Expression of estrus was not influenced by age (P = 0.31), or treatment (P = 0.60), however, there was a treatment by age interaction (P \u3c 0.01) for expression of estrus. For animals administered the 5 + 5 μg treatment, expression of estrus was increased (P \u3c 0.01) among heifers compared to cows (84 ± 3% vs 70 ± 3%, respectively). Pregnancy success was influenced by estrus (P \u3c 0.01), treatment (P = 0.02), and a treatment by estrus (P \u3c 0.01) interaction, but was not influenced by age (P = 0.91), treatment by age (P = 0.83), or treatment by estrus by age (P = 0.94). Animals that exhibited estrus had increased pregnancy success compared to animals that did not exhibit estrus (67 ± 2% vs 41 ± 7% respectively). Animals administered the 5 + 5 μg treatment had increased pregnancy success (P ≤ 0.05; 69 ± 6%) compared to animals administered the 0 μg and 10 μg treatments which did not differ (53 ± 6% vs 41 ± 8%, respectively). Pregnancy success was similar (P \u3e 0.27) between animals that did and did not exhibit estrus for animals administered the 0 μg and 5 + 5 μg treatments. For animals administered the 10 μg treatment, conception rates were decreased (P \u3c 0.01) among animals that did not exhibit estrus compared to animals that exhibited estrus. This study demonstrated that the 5 + 5 μg treatment of GnRH following CIDR removal, when implementing a fixed-time AI protocol, positively influenced conception rates. In Chapter 5, beef cows/heifers were synchronized using the CO-Synch protocol and artificially inseminated. On day 16 after insemination animals were transported to a local abattoir. Following slaughter ovaries were collected and all follicles were classified as small (\u3c 5 mm), medium (5 to 10 mm), or large (\u3e 10 mm). Follicles were aspirated to collect follicular fluid and granulosa cells. Follicles were pooled by size within animal (n = 23, 16, and 18 for small, medium, and large, respectively). Follicular fluid concentrations of estradiol were determined by radioimmunoassay. Total cellular RNA was extracted from the granulosa cells and RT-PCR was performed to determine relative abundance of mRNA for GnRH-I, GnRH-II, and GAPDH. Data were analyzed using the mixed procedure in SAS. Follicle size influenced concentration of estradiol. Large follicles had increased estradiol (P \u3c 0.0001) compared to small and medium follicles (18,626 ± 2,650 vs 1,270 ± 2,307 and 8,925 ± 2,763 pg/mL, respectively). There was no difference (P = 0.31) in relative abundance of GnRH-I mRNA among small, medium, or large follicles (3.8 ± 0.78, 3.40 ± 0.85, and 1.95 ± 0.94; respectively). Relative abundance of GnRH-II mRNA was influenced by follicle size (P \u3c 0.05), with greater abundance in small follicles (40.97 ± 9.27) compared to medium (6.32 ± 11; P = 0.02) or large (7.85 ± 11.11; P = 0.02) follicles. However, there was no difference (P = 0.92) in relative abundance between medium and large follicles. When follicles were classified by concentration of estradiol, follicles with the lowest 25% of estradiol had decreased (LOWE2; P \u3c 0.0001) concentrations of estradiol (434 ± 1,074 pg/mL) compared to the middle 50% (MIDE2; 7,029 ± 961 pg/mL) which was decreased (P \u3c 0.0001) compared to the greatest 25% (HIGHE2; 46,423 ± 2,025 pg/mL). LOWE2 had greater (P \u3c 0.01; 5.37 ± 0.67) abundance of GnRH-I mRNA compared to MIDE2 and HIGHE2 which did not differ (1.85 ± 0.55 and 1.23 ± 1.65, respectively). Relative abundance of GnRH-II mRNA was greater (P \u3c 0.01) in LOWE2 (42.33 ± 9.56) compared to MIDE2 (5.98 ± 8.90). HIGHE2 was similar (P ≥ 0.12) to the other two groups (8.90 ± 19.12). Results from this study demonstrate a relationship between granulosa cell GnRH-I and II mRNA abundance with estradiol concentrations within the follicle, where decreased GnRH-I and GnRH-II may be playing a role in increased estradiol production. These three experiments demonstrate GnRH directly impacting estradiol, and/or reproductive performance of beef cows and heifers through interval to estrus, expression of estrus, and increasing conception rates when used with FTAI protocols. The mechanisms by which GnRH is having its actions remains to be elucidated

The slow death (or rebirth?) of extended star formation in z∼0.1z \sim 0.1 green valley early-type galaxies

UV observations in the local universe have uncovered a population of early-type galaxies with UV flux consistent with low-level recent or ongoing star formation. Understanding the origin of such star formation remains an open issue. We present resolved UV-optical photometry of a sample of 19 Sloan Digital Sky Survey (SDSS) early-type galaxies at $z \sim 0.1$ drawn from the sample originally selected by Salim & Rich to lie in the bluer part of the green valley in the UV-optical color-magnitude diagram as measured by the $\textit{Galaxy Evolution Explorer (GALEX)}$. Utilizing high-resolution $\textit{Hubble Space Telescope (HST)}$ far-UV imaging provides unique insight into the distribution of UV light in these galaxies, which we call "extended star-forming early-type galaxies" (ESF-ETGs) because of extended UV emission that is indicative of recent star formation. The UV-optical color profiles of all ESF-ETGs show red centers and blue outer parts. Their outer colors require the existence of a significant underlying population of older stars in the UV-bright regions. An analysis of stacked SDSS spectra reveals weak LINER-like emission in their centers. Using a cross-matched SDSS DR7/$GALEX$ GR6 catalog, we search for other green valley galaxies with similar properties to these ESF-ETGs and estimate that $\approx 13$ of dust-corrected green valley galaxies of similar stellar mass and UV-optical color are likely ESF-candidates, i.e., ESF-ETGs are not rare. Our results are consistent with star formation that is gradually declining in existing disks, i.e., the ESF-ETGs are evolving onto the red sequence for the first time, or with rejuvenated star formation due to accreted gas in older disks provided that the gas does not disrupt the structure of the galaxy and the resulting star formation is not too recent and bursty. ESF-ETGs may typify an important subpopulation of galaxies that can linger in the green valley for up to several Gyrs, based on their resemblance to nearby gas-rich green valley galaxies with low-level ongoing star formation

Effect of Estrous Synchronization With Natural Service or Fixed-Timed Artificial Insemination Using Conventional or Gender-Kkewed Semen in Beef Females on Calving Distribution and Post Weaning Calf Performance

Study Description: Within 10 herds, beef females (n = 1,620) were either: 1) not synchronized (NonSyn) and mated to bulls, 2) synchronized (7-d controlled internal drug release (CIDR)) and mated to bulls (SynNS) 3) synchronized (7-d CO-Synch plus CIDR) and artificially inseminated with conventional semen (SynAI), or 4) synchronized (7-d CO-Synch plus CIDR) and artificially inseminated with SEXED semen. Calving distributions (calves born from d 1 to 14, 1 to 21, 22 to 42, and 43 and greater) were determined by actual birthdates and calf gender was determined at birth. Over a two-year period, a subset of calves (n = 508) born to cows subjected to the previously discussed reproductive treatments in each of the 10 herds were fed to reach a target backfat (BF) of 0.50 inches, sent to harvest, and carcass data were collected. Calves were classified into calving groups as natural service born early (NS-Early, n = 189), natural service born late (NS-Late, n = 203), or AI sired born early (AI-Early, n = 116). Early was defined as the first 21 days of the calving season

Influence of estradiol on bovine trophectoderm and uterine gene transcripts around maternal recognition of pregnancy

Embryo survival and pregnancy success is increased among animals that exhibit estrus prior to fixed time-artificial insemination, but there are no differences in conceptus survival to d16. The objective of this study was to determine effects of preovulatory estradiol on uterine transcriptomes, select trophectoderm (TE) transcripts, and uterine luminal fluid proteins. Beef cows/heifers were synchronized, artificially inseminated (d0), and grouped into either high (highE2) or low (lowE2) preovulatory estradiol. Uteri were flushed (d16); conceptuses and endometrial biopsies (n = 29) were collected. RNA sequencing was performed on endometrium. Real-time polymerase chain reaction (RT-PCR) was performed on TE (n = 21) RNA to measure relative abundance of IFNT, PTGS2, TM4SF1, C3, FGFR2, and GAPDH. Uterine fluid was analyzed using 2D Liquid Chromatography with tandem mass spectrometry-based Isobaric tags for relative and absolute quantitation (iTRAQ) method. RT-PCR data were analyzed using the MIXED procedure in SAS. There were no differences in messenger RNA (mRNA) abundances in TE, but there were 432 differentially expressed genes (253 downregulated, 179 upregulated) in highE2/conceptus versus lowE2/conceptus groups. There were also 48 differentially expressed proteins (19 upregulated, 29 downregulated); 6 of these were differentially expressed (FDR \u3c 0.10) at the mRNA level. Similar pathways for mRNA and proteins included: calcium signaling, protein kinase A signaling, and corticotropin-releasing hormone signaling. These differences in uterine function may be preparing the conceptus for improved likelihood of survival after d16 among highE2 animals

A Measurement of Parity-Violating Neutron Transmission in Xenon

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Environmental Management Maturity: The Role of Dynamic Validation.

Maturity models enhance the performance of companies by prescribing a trajectory through stages of increasing capability. However, a recent review of maturity models concludes that current maturity models hardly meet the design principles required for prescriptive use. To address this deficiency, we conducted semistructured interviews and a Group Model Building study with industrial companies in Spain in which we studied the progression toward a Leading Green Company as the highest maturity stage of environmental management. The findings from the study were tested using surveys with enterprises in Spain, Italy, and the United Kingdom, semistructured interviews in the United Kingdom and case studies in Spain. Using these data sources, we develop a causal model that captures an idealized environmental management maturity dynamic progression though stages. By mapping maturity stages to feedback loops connected to actions to improve those maturity levels, system dynamics can help companies articulate policies for transitioning toward higher maturity stages

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

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

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

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

Use of Pregnancy Associated Glycoproteins to Determine Fetal Age Throughout Gestation in Cattle

Objective The objective of the current study was to determine if a commercially available blood pregnancy test could be modified to detect differences in pregnancy-associated glycoprotein (PAG) concentrations to indicate stage of pregnancy or fetal age in cattle. Study Description Previously identified pregnant females were grouped by age (pre-primiparous or multiparous). Blood samples were collected between day 27 and 190 of pregnancy (n = 176 from pre-primiparous and n = 240 from multiparous) and serum was tested in duplicate using a commercially available blood pregnancy test, IDEXX Alertys Pregnancy Test. Procedures were adapted to allow concentrations to fall within the detectible range of the assay. Animals were grouped by parity (pre-primiparous vs multiparous) into 4 gestational groups (group 1 - \u3c 30 days, group 2 - 30 to 90 days, group 3 - 91 to 178 days, and group 4 - \u3e178 days). Data were analyzed using the MIXED procedure of SAS with parity and gestational age in the model. There was an effect of parity, gestational age, and a parity by gestational age interaction (P \u3c 0.01). Pre-primiparous animals had greater concentrations of PAGs compared to multiparous animals. Among pre-primiparous animals, serum PAG concentrations did not differ between gestational age groups 1, 2, or 3 (P \u3e 0.37), but group 4 had greater PAG concentrations than all other groups (P \u3c 0.01). Among multiparous animals, serum PAG concentrations decreased from group 1 to 2 (P \u3c 0.01), and then increased throughout gestation (P \u3c 0.01). Data were then analyzed using the REG procedure in SAS within gestational age group. There was a positive correlation between gestational age and PAG concentrations among both pre-primiparous (P \u3c 0.01; R2 = 0.25) and multiparous (gestational age 30 and greater P \u3c 0.01; R2 = 0.64)

Use of Pregnancy Associated Glycoproteins to Determine Fetal Age Throughout Gestation and Clearance Rate in Postpartum Beef Cattle

Study Description: Previously identified pregnant females from four different herds and postpartum females from one herd were utilized. Blood samples were collected (n = 1,753; study 1) between d 28 and 285 of gestation and (heifers n = 418 and cows n = 657; study 2) once a week for up to 12 weeks after calving. Serum was tested in duplicate using a commercially available blood pregnancy test, IDEXX Alertys Pregnancy Test. In study 1, procedures were modified to allow PAG concentrations to fall within the detectible range of the assay. Data were analyzed using the MIXED procedure of SAS with cow age and gestational age (also divided into four gestational age groups: 1) \u3c 30 d; 2) 30-90 d; 3) 91-180 d; 4) \u3e 180 d) in the model and then analyzed further using the REG procedure in SAS within gestational age group. In study 2, data were analyzed as repeated measure using the MIXED procedure of SAS with cow age, days postpartum (dpp), and cow age by dpp in the model, then data were analyzed further using the REG procedure in SAS. In study 1, there was a significant effect of gestational age and cow age by gestational age interaction (P \u3c 0.01) as well as a tendency of cow age (P = 0.08). Among heifers and cows, serum PAG concentrations did not differ between gestational age groups 1 and 2 (P \u3e 0.84), however, PAG concentrations differed between groups 2 and 3 (P \u3c 0.0001) and 3 and 4 (P \u3c 0.0001). There was a positive correlation between gestational age and PAG concentrations (P \u3c 0.01; r2 = 0.2604). In study 2, there was a significant effect of days postpartum (dpp; P \u3c 0.01) on PAG concentrations; however, PAG concentrations were not influenced by cow age (P = 0.73) or cow age by dpp (P = 0.55). Concentrations of PAGs rapidly decreased from d 0 to 50 postpartum and then continued to gradually decrease (P \u3c 0.01; r2 = 0.8083). Prior to 42 dpp, PAG concentrations were sufficiently elevated which resulted in false positive readings