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Controlled Internal Drug Release (CIDR) devices have become an important component of reproductive management programs in many beef herds. When a CIDR is inserted into a cow, circulating concentrations of progesterone mimic a functional corpus luteum. Some data, however, suggest that concentration of progesterone following insertion of a CIDR might have negative consequences on fertility in Bos indicus animals. Therefore, the objective of this study was to determine the impact of a CIDR device on circulating and uterine tissue concentrations of progesterone. A blood sample and a uterine biopsy were collected from non-suckled postpartum cycling Brahman cows (n = 10; Cycling) during the midluteal stage. A blood sample and a uterine biopsy were also collected from non-suckled postpartum cycling Brahman cows (n = 9; CIDR) after a CIDR had been in place for 5 d. To collect uterine biopsies from CIDR cows, the uterine biopsy tool was placed inside a plastic covering, both were passed into the cervix of the cow before the tool was extended through the covering and into the uterus. After the biopsy was collected, the tool was carefully removed to prevent sample contamination. Blood samples were centrifuged, and serum was collected to determine concentrations of progesterone. Uterine biopsies were snap frozen until extraction. Biopsies were weighted, thawed, and homogenized in assay buffer. Samples were then extracted with methyl tert-butyl ether and resuspended in assay buffer. Serum concentrations are reported as ng/mL and uterine concentrations are reported as ng/g. Statistical analysis was performed using the GLM procedure in SAS with treatment (CIDR vs Cycling), tissue type (uterine vs serum) and their interaction included in the model. There was a significant effect of treatment (P = 0.0062), tissue (P = 0.0063) and a treatment by tissue interaction (P = 0.0068). Animals with a CIDR had greater concentrations of progesterone than Cycling animals (274.77 vs 4.37 ng, respectively). Uterine samples had greater concentrations of progesterone than serum samples (274.40 vs 4.74 ng, respectively). These increased concentrations of progesterone were mainly from CIDR uterine samples (543.24 ng/g) which had greater (P < 0.001) concentrations of progesterone compared with all other samples, which did not differ from each other (P > 0.98; CIDR Serum 6.29 ng/mL, Cycling Serum 3.2 ng/mL, and Cycling Uterus 5.54 ng/g). In summary, CIDRs increased circulating concentrations of progesterone sufficient to keep animals from exhibiting estrus, and were not different from cows in the midluteal stage of their cycle. Local concentrations in uterine tissue; however, were significantly greater when a CIDR was in place compared with uterine tissue collected during the midluteal phase. The implications of these significantly greater concentrations of progesterone in uterine tissue warrant further investigation. [ABSTRACT FROM AUTHOR]

This experiment investigated the effects of diet composition on rumen, vaginal, and uterine microbiota of beef heifers. Fifteen rumen-cannulated, pubertal Angus-influenced heifers were used in a replicated 3 × 3 Latin square design (28-d periods and 21-d washout intervals). Dietary treatments included diets based on (as-fed) 100% grass hay (HF), 60% grass hay + 40% corn-based concentrate (INT), or 25% grass hay + 75% corn-based concentrate (HG). Treatments were offered individually to heifers once daily at 2% body weight. Rumen, vaginal, and uterine samples were collected on days 0 and 28 of each period. Data were analyzed using orthogonal contrasts (linear and quadratic), using results from day 0 as independent covariates and heifer as the experimental unit. Ruminal pH on day 28 decreased linearly (P < 0.01) as concentrate inclusion increased. Uterine and vaginal pH on day 28 were not affected by treatments (P ≥ 0.35). Within the rumen samples, Bacteriodetes was the most abundant phylum and its relative abundance linearly decreased (P ≤ 0.01) with the inclusion of concentrate. Prevotella was the most abundant genus within the rumen but was not affected by treatments (P ≥ 0.44). Genera with relative abundance ≥1% (average across treatments) in the rumen that were impacted by treatments (P ≤ 0.01) included Bacteroides , Pedobacter , Dysgonomonas , Caloramator, and Ruminococcus. Firmicutes was the most abundant phylum in the vagina and uterus, but it was unaffected by treatments (P ≥ 0.16). Prevotella was the most abundant genus in the vagina, and its relative abundance increased (P < 0.01) with the inclusion of concentrate. Other genera with relative abundance ≥1% that were significantly affected (P ≤ 0.05) by treatments were Clostridium, Pedobacter , Roseburia, Oscillospira, Faecalibacterium, Caloramator, Paludibacter, Rhodothermus, and Porphyromonas. In uterine samples , Prevotella was the most abundant genus but was unaffected by treatments (P ≥ 0.29). Genera with relative abundance ≥1% in the uterus that were significantly affected (P < 0.01) by treatments were Caloramator , Paludibacter , and Thalassospira. Collectively, inclusion of concentrate in the diet altered the bacterial composition within the rumen as well as shifting bacterial populations within the vagina and uterus. Research is warranted to further understand the impacts of these diet-induced microbiota changes on reproductive function and performance of beef heifers. [ABSTRACT FROM AUTHOR]

The transition from gestation to lactation, also known as the transition period, is a critical time for dairy cows. This phase is typically defined as 3 weeks before parturition through 3 weeks after parturition. Peak disease incidence (shortly after parturition) corresponds with the time of greatest negative energy balance (NEB) and negative protein balance (NPB), the peak in blood concentrations of nonesterified fatty acids, and the greatest acceleration of milk yield. Decreased fertility in the face of increasing milk production may be attributable to greater severity of postpartum NEB and NPB resulting from inadequate transition management or increased disease rates. The depth and duration of NEB and NPB are highly related to dry matter intake. Formulating and delivering appropriate diets that limit total energy intake to requirements but also provide proper intakes of all other nutrients [including the indispensable amino acids (IAA) Met and Lys] before calving can help lessen the extent of NEB and NPB after calving. Supplementation of rumen-protected methionine (RPM) during the transition period improved uterine immune function through improved glandular morphology, increased neutrophil infiltration after calving, and discovery of neutrophil extracellular trap formation in bovine endometrial tissue. Its supplementation has been reported to reduce the incidence of health complications, better lactation performance, and more favorable biomarker and plasma AA profiles, common in cows with increased liver functionality index. Cows supplemented with rumen-protected lysine (RPL) had decreased liver oxidative stress (SOD1, superoxide dismutase 1) and acute phase response (SAA3, serum amyloid A3) and reduced gene expression of NFKB1 (nuclear factor kappa B1) leading to increased proinflammatory IL1B postpartum, likely indicating improved immune activation when cows consumed RPL, a necessary component of early postpartum health. Our group has reported that a prepartum supply of RPL altered uteroplacental metabolism and glucose transport. This was demonstrated through increased expression of uterine transcripts involved in energy metabolism (GLUT3, glucose transporter 3; PCK1, phosphoenolpyruvate carboxykinase 1) and placental metabolism (FGF2, fibroblast growth factor 2; FGF2R, fibroblast growth factor 2 receptor; and PGF, placental growth factor). We also have demonstrated that RPL prepartum increased the placental protein abundance of FGF2 and LRP1 (low-density lipoprotein receptor-related protein 1), indicating possible enhanced placental metabolic activity, probably linked to trophoblast proliferation and migration processes. Finally, calves from dams fed RPL prepartum had improved overall growth and intake than calves from dams not receiving RPL. In conclusion, providing RPM and RPL during the transition period impacts dairy cows' health, uterine environment, and offspring. [ABSTRACT FROM AUTHOR]

Female sex steroid hormones have been shown to interact with cytokines within the immune system to help influence fertility. Previous research has indicated that shifts in commensal bacteria are associated with compromised reproductive performance during the postpartum period, yet evaluation of how the female sex hormone progesterone (P4) influences these microbial shifts is not fully understood. The objectives of this study were to determine 1) the relationship between P4 concentrations and cytokine concentrations, and 2) the relationship between P4 concentrations and the reproductive microbiome. Twenty Bos indicusinfluenced beef cows (~60 days postpartum and free of health issues) were weighed, body condition scored and then subjected to the Bos indicus prostaglandin 5 day (d) + CIDR protocol beginning on d-8 and timed artificially inseminated on d 0. Blood samples were collected on d-3, -1, 0, and 28. Cytokines and reproductive microbiome were evaluated using vaginal and uterine flushes collected on d -3 and d-1. Experimental groups were assigned by d 28 pregnancy status, determined by transrectal ultrasonography, resulting in Open (n = 13) and Pregnant (n = 7) females. Bacterial community analyses were conducted targeting the V4 hypervariable region of the 16S rRNA gene. Plasma P4 concentrations on d -3 and d -1 were quantified per manufacturers' instructions using a double-antibody RIA kit. Cytokine analyses of plasma and flushes were conducted using the RayBiotech Quantibody Bovine Cytokine Array Q1 kit per the manufacturer's instructions. Statistical analyses were conducted using the GLM procedure and CORR procedure in SAS. Plasma P4 concentrations did not differ by pregnancy status (P > 0.05) but did decrease from d -3 to d -1 (0.89 vs. 0.08 ± 0.23 ng/mL, respectively; P = 0.02). There were no significant correlations between plasma P4 and plasma cytokines (P > 0.05). Interferon-alpha (IFNa) and P4 concentrations were positively correlated in Open and Pregnant uterine flushes (r = 0.41; P = 0.01). Concentrations of P4 interleukin (IL)-1F5 were negatively correlated in Open and Pregnant vaginal flushes (r = -0.32; P = 0.04). The relative abundance of genus Methanobrevibacter in uterine flushes was positively correlated with P4 concentrations in both experimental groups (r = 0.35; P = 0.02). Within vaginal flushes, there was a tendency for a negative correlation between the relative abundance of genus Bacteroides and P4 concentrations (r = -0.31; P = 0.05). Alternatively, there is a positive correlation between P4 concentration and relative abundance of genus Streptococcus (r = 0.47; P = 0.01) and genus Methanobrevibacter (r = 0.37; P = 0.02) in vaginal flushes. These results suggest there may be relationships between several cytokines and circulating P4 concentrations; therefore, potentially suggesting immunomodulatory activities of P4. Overall, this research alludes to P4 having a vital role in reproductive microbial shifts and associated immune responses. Further investigation on the local effects of P4 within the reproductive tract on immune responses and bacterial shifts could provide greater insight into mechanisms to improve fertility in beef cattle. [ABSTRACT FROM AUTHOR]

The present study evaluated the bovine vaginal and uterine bacterial community diversity and its relationship to fertility. Postpartum beef cows (n = 68) were synchronized beginning on day −21 and ending with timed artificial insemination (TAI) on day 0. Pregnancy was diagnosed 30 d after TAI. Uterine and vaginal flushes were collected on day −21, −9, and −2 for bacterial DNA extraction to sequence the V1 to V3 hypervariable regions of the 16S rRNA gene. Results indicated a decrease in the number of bacterial species over time in the uterus of resulting pregnant and nonpregnant beef cows (P < 0.0001). Principal coordinate analyses (PCoA) depicted clustering of samples, indicating closely related bacterial communities, by day in the uterus and vagina (P < 0.0001). At day −2, uterine samples from nonpregnant and pregnant animals clustered separately (P < 0.0001), with nonpregnant animal samples clustering tightly together. Overall, the current study suggests the shift in the reproductive bacterial communities' diversity and phylogenetic relationship leading up to the time of breeding may contribute to successful pregnancy establishment. [ABSTRACT FROM AUTHOR]

The current study characterized the taxonomic composition of the uterine and vaginal bacterial communities during estrous synchronization up to timed artificial insemination (TAI). Postpartum beef cows (n = 68) were subjected to pre-synchronization step 21 d prior to TAI (day −21), followed by an industry standard 7 Day Co-Synch on day −9 and TAI on day 0. Uterine and vaginal flushes were collected on days −21, −9, and −2 of the protocol and pH was immediately recorded. Pregnancy was determined by transrectal ultrasound on day 30. Bacterial DNA was extracted and sequenced targeting the V1 to V3 hypervariable regions of the 16S rRNA bacterial gene. Results indicated 34 different phyla including 792 different genera present between the uterus and vagina. Many differences in the relative abundance of bacterial phyla and genera occurred between resulting pregnancy statuses and among protocol days (P < 0.05). At day −2, multiple genera were present in >1% abundance of nonpregnant cows but <1% abundance in pregnant cows (P < 0.05). Uterine pH increased in nonpregnant cows but decreased in pregnant cows (P > 0.05). Overall, our study indicates bacterial phyla and genera abundances shift over time and may potentially affect fertility by altering the reproductive tract environment. [ABSTRACT FROM AUTHOR]

In 1953, Sir Peter Medawar first recognized the allogeneic properties of a developing conceptus and rationalized that an "immune-tolerant" physiological state must exist during pregnancy. Early theories speculated that the conceptus evaded the maternal immune system completely, but 40 yr after Medawar's observations, Wegmann proposed that the maternal immune system shifts the cytokine profile away from inflammatory cytokine production when an embryo is present. The economic consequences and production losses of subfertile animals have been well documented in studies evaluating calving distribution. Despite advances in understanding infertility or subfertility, few technologies exist to identify subfertile animals or improve fertility beyond hormonal intervention associated with synchronization protocols. Work in rodents and some livestock species indicates that the uterine immune cell population shifts dramatically after copulation and these early immune-modulated events establish a receptive uterine environment. Clearly, as evident in embryo transfer, the presence of a conceptus is sufficient to establish communication for pregnancy establishment but does not rule out the importance of other physiological events to prime the maternal immune system prior to blastocyst arrival in the uterus. In support of this concept, work in our laboratory and by others has demonstrated that autologous intrauterine transfer of peripheral immune cells prior to embryo transfer can increase pregnancy rates and accelerate conceptus development in women and cattle. Understanding aberrant immune regulation in subfertile animals may provide markers for subfertility or targets for clinical intervention to enhance fertility, particularly when using reproductive technologies. [ABSTRACT FROM AUTHOR]

In 1953, Sir Peter Medawar first recognized the allogeneic properties of a developing conceptus and rationalized that an "immune-tolerant" physiological state must exist during pregnancy. Early theories speculated that the conceptus evaded the maternal immune system completely, but 40 yr after Medawar's observations, Wegmann proposed that the maternal immune system shifts the cytokine profile away from inflammatory cytokine production when an embryo is present. The economic consequences and production losses of subfertile animals have been well documented in studies evaluating calving distribution. Despite advances in understanding infertility or subfertility, few technologies exist to identify subfertile animals or improve fertility beyond hormonal intervention associated with synchronization protocols. Work in rodents and some livestock species indicates that the uterine immune cell population shifts dramatically after copulation and these early immune-modulated events establish a receptive uterine environment. Clearly, as evident in embryo transfer, the presence of a conceptus is sufficient to establish communication for pregnancy establishment but does not rule out the importance of other physiological events to prime the maternal immune system prior to blastocyst arrival in the uterus. In support of this concept, work in our laboratory and by others has demonstrated that autologous intrauterine transfer of peripheral immune cells prior to embryo transfer can increase pregnancy rates and accelerate conceptus development in women and cattle. Understanding aberrant immune regulation in subfertile animals may provide markers for subfertility or targets for clinical intervention to enhance fertility, particularly when using reproductive technologies. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of orexin B (OXB) on progesterone (P4) and androstenedione (A4) secretion by porcine endometrial and myometrial tissue explants and on the expression of key steroidogenic proteins and enzymes involved in steroid production. The hormones secretion and the expression of steroidogenic acute regulatory protein (StAR), P450 side-chain cleavage enzyme (CYP11A1), and 3β-hydroxysteroid dehydrogenase (HSD3B1) were analyzed on days 10 to 11, 12 to 13, 15 to 16, and 27 to 28 of pregnancy and during the luteal phase of the estrous cycle (days 10 to 11). Endometrial and myometrial explants were cultured in vitro in the presence of OXB (1, 10, or 100 nM) and OXB (1, 10, or 100 nM) with 1 µM of JNJ (OX2R antagonist). Gene expression was examined by real-time PCR, and steroid secretion was determined by radioimmunoassay. Orexin B modulated StAR , CYP11A1 , HSD3B1 mRNA content depending on the type of uterine tissue, the applied OXB dose, and the stage of pregnancy or the estrous cycle (P < 0.05). Orexin B increased P4 secretion in all stages of early gestation (P < 0.05). Orexin B enhanced the release of A4 on days 12 to 13, 15 to 16, and 27 to 28 of gestation, whereas on days 10 to 11 of early pregnancy, A4 secretion decreased in the endometrium and increased in the myometrium (P < 0.05). These results indicate that OXB affects the expression of key steroidogenic regulators and the secretion of steroid hormones in the porcine uterus during early pregnancy. [ABSTRACT FROM AUTHOR]

An accurate understanding of the AA composition of the products of conception is needed to accurately model dietary AA needs of pregnant swine. To determine AA composition in fetal pigs, the placenta, and the uterus at various stages of gestation, samples from a total of 65 gilts slaughtered at assigned days of gestation (d 43, 58, 73, 91, 101, and 108) were used. The AA concentrations (g/kg each wet tissue) in the fetus, placenta, or uterus increased as gestation progressed, with major increases occurring from d 73 to 108 of gestation (P < 0.05). For fetus, AA content on a DM basis (%) and AA contribution to total fetal AA (g/100 g total AA of fetal tissue) generally decreased as gestation progressed (P < 0.05) except for Arg and Ala, which increased from d 73 of gestation, and for Gly and Pro, which increased progressively (P < 0.05) from d 43. Placental AA content on a DM basis increased up to d 91 or 101 of gestation (P < 0.05) and then slightly decreased on d 108 of gestation except for His, Cys, and Met + Cys. Amino acid contribution to total placental AA decreased for all AA as gestation progressed (P < 0.05), except for Arg, Ala, Gly, and Pro, which increased from d 58 of gestation. Essential AA content in the uterus on a DM basis had no major changes during gestation, whereas nonessential AA content decreased (P < 0.05) as gestation progressed, except for Asp. For AA contribution to total uterine AA, some essential AA (Ile, Leu, Lys, Met, Trp, and Val; P < 0.06) and Asp (P < 0.01) contributions increased with increasing gestational ages, whereas Arg (P = 0.08), Cys, Gly, and Pro (P < 0.05) contributions decreased as gestation progressed. Differences in AA contribution to total AA within each tissue varied among the fetus, placenta, and uterus by type of AA. These results demonstrate that AA compositions of fetal pigs, placenta, and uterus are changed differentially as gestation progresses; in particular, Arg, Ala, Gly, and Pro compositions in fetus and placenta increased progressively. These compositional data for each reproductive tissue and fetus will help to model AA requirements in gestation. [ABSTRACT FROM AUTHOR]

Google Scholar OpenURL Placeholder Text WorldCat 3 Mathew, D. J., K. D. Peterson, L. K. Senn, M. A. Oliver, and A. D. Ealy. Graph Members of the NE1727 Multistate Research Project: Influence of Ovary, Uterus, and Embryo on Pregnancy Success in Ruminants have compiled a set of manuscripts that represents their past and current efforts defining the factors underlying and affecting maternal recognition of pregnancy and embryo survival in cattle ([3]). Google Scholar OpenURL Placeholder Text WorldCat 4 McCoski, S. R., R. R. Cockrum, and A. D. Ealy. [Extracted from the article]

During early gestation, nutrients are transported to the developing embryo via transporters in the uterine endometrium and chorioallantois. In the present study, we examined glucose transporters GLUT1 and GLUT3 and the cationic AA transporters SLC7A1, SLC7A2, and SLC7A3 to test the hypotheses that 1) relative mRNA expression of transporters would be different among uteroplacental tissue type as gestation progresses and 2) concentrations of glucose and cationic AA would be different among target sites (placental compartments, serum, and histotrophic) and days of gestation. To test these hypotheses, crossbred Angus heifers (n = 46) were synchronized, bred via AI, and then ovariohysterectomized on d 16, 22, 28, 34, 40, or 50 of gestation (5 to 9/d) or not bred and ovariohysterectomized on d 16 of the synchronized estrous cycle (n = 7) to serve as nonpregnant (NP) controls. Uteroplacental tissues (maternal caruncle [CAR], intercaruncular endometrium [ICAR], and fetal membranes [FM; chorioallantois, d 22 and later]) were collected from the uterine horn ipsilateral to the corpus luteum immediately following ovariohysterectomy. Relative mRNA expression of the glucose transporters and cationic AA transporters was determined for each tissue from d 16 to 50 of gestation and from NP controls. Chorioallantoic, amniotic, and plasma fluids were collected from heifers on d 40 and 50 of gestation to determine concentrations of glucose and cationic AA. Expression of GLUT1 and SLC7A2 showed a tendency (P < 0.10) toward being greater in d 16 ICAR and d 34 ICAR, respectively. Day × tissue interactions (P < 0.05) were present for GLUT3, SLC7A1, and SLC7A3. Expression of GLUT3 was greater in d 50 CAR, expression of SLC7A1 was greater on d 34 in ICAR, and expression of SLC7A3 was greater in CAR tissue on d 34 compared with all other tissues and days of gestation. Glucose concentrations tended (P = 0.10) to be impacted by a day × fluid interaction. A day × fluid interaction (P = 0.01) for arginine concentration was observed, with greater concentrations in allantoic fluid on d 40 compared with all other days and fluid types. These data support our hypothesis that glucose and cationic AA transporters differ in their level of mRNA expression due to day of gestation and uteroplacental tissue type. In addition, concentrations of nutrients were differentially impacted by day, target site, and/or their respective interaction. [ABSTRACT FROM AUTHOR]

The preweaning litter environment of gilts can affect subsequent development. In a recent experiment designed to test the effects of diet on gilt development, litter-of-origin traits including individual birth weights, immunocrits (a measure of colostrum intake), sow parity, number weaned, and individual weaning weights were collected for approximately 1,200 gilts that were progeny of approximately 300 sows. Subsequently, BW, LM area, and backfat were measured at 100 d of age and at 28-d intervals until slaughter (260 d of age). From 160 d of age to slaughter, gilts were observed daily for estrus. At slaughter, the reproductive tract and 1 mammary gland were recovered. The reproductive tract was classified as cyclic or prepubertal; the number of corpora lutea was counted. Uterine horn lengths and ovarian dimensions were measured. Uterus and ovary samples from every 10th gilt were prepared for histological evaluation of uterine gland development and follicle counts, respectively. Mammary gland tissue protein and fat were assayed. Day of the estrous cycle at slaughter was calculated using the first day of the most recent standing estrus (d 0) recorded previous to slaughter. Each gilt development trait was analyzed for association with each litter-of-origin trait, after adjusting for dietary treatment effects. Uterine length, ovarian dimensions, mammary gland protein and fat, and uterine gland development were also adjusted for day of the estrous cycle at slaughter. All litter-of-origin traits were associated (P < 0.05) with growth traits. Top-down (backward elimination) multiple regression analysis indicated that BW and LM accretion in gilts was positively associated with immunocrit (P < 0.01), birth weight (P < 0.01), preweaning growth rate (P < 0.01), and parity (P < 0.01). Backfat accretion was positively associated with preweaning growth rate (P < 0.01), number weaned (P < 0.05), and parity (P < 0.05). Age at puberty was associated with birth weight (positive; P < 0.01) and preweaning growth rate (negative; P < 0.01). Total uterine length was positively associated with only birth weights (P < 0.05). Mammary gland protein was negatively associated with preweaning growth (P < 0.01). Mammary gland fat was positively associated with birth weight and number of piglets weaned (P > 0.05). These results indicate that colostrum consumption, birth weights, preweaning growth rate, number weaned, and parity are associated with gilt development traits during later life. [ABSTRACT FROM AUTHOR]

Uterine contamination with bacteria is ubiquitous in the postpartum dairy cow. Nearly one-half of all postpartum dairy cows develop clinical disease resulting in metritis and endometritis, which cause depressed milk production and infertility. The causative links between uterine infection and infertility include a hostile uterine environment, disrupted endocrine signaling, and perturbations in ovarian function and oocyte development. In this review we consider the various mechanisms linking uterine infection with infertility in the dairy cow, specifically 1) innate immune signaling in the endometrium, 2) alteration in endocrine signaling in response to infectious agents, and 3) impacts of infection on ovarian function, oocyte development, and follicular development. Normal ovarian follicular and oocyte development requires a series of temporally and spatially orchestrated events; however, several of the cellular pathways required for ovarian function are also used during the innate immune response to bacterial pathogens. We propose that activation of cellular pathways during this immune response has a negative impact on ovarian physiology, which is manifest as infertility detected after the clearance of the bacteria. This review highlights how new insights into infection and immunity in cattle are linked to infertility. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) have been used as biomarkers for various health issues and physiological states, and could be utilized as a tool to detect pregnancy loss. The objective of this study was to determine the variation in miRNA abundance between pregnant and non-pregnant uteri of cows at day 30 post-insemination. Uterine samples were collected from pregnant (n = 4) and non-pregnant (n = 4) cows, and snap frozen in liquid N2. Isolation of uterine RNA was performed using the mirVANA kit and RNA quantification and quality assessed. Eight libraries were generated (4 biological replicates per group) and subjected to RNAseq procedures and bioinformatic analysis by LC Sciences (Houston, TX, USA). Raw sequence data were analyzed using the ACGT101-miR program (LC Sciences, Houston, TX) removing extraneous sequence information. The remaining sequences ranging in size for 18 to 26 nucleotides were mapped to known bovine miRNA sequences (miRbase 22.1) and the bovine genome. Significant and differentially abundant miRNAs were analyzed using normalized deep sequencing counts and were subjected to ANOVA (P < 0.05). There were 55 significant (P < 0.05) differentially abundant microRNAs of which 35 were upregulated in open samples and 20 were upregulated in pregnant samples. Target prediction was performed using TargetScan for differentially abundant miRNA. Functional enrichment analysis of the miRNA target genes was conducted using the Database for Annotation, Visualization and Integrated Discovery (DAVID 2021). Gene targets were analyzed using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. The top 5 KEGG pathways across all significant and differentially abundant miRNAs were pathways in cancer, PI3K-Akt signaling pathway, MAPK signaling pathway, human papillomavirus infection, and metabolic pathways. These results show that there is variation in the abundance of miRNAs between pregnant and open cows at day 30 post-insemination. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of estrus expression on uterine microbiota composition of cows on day 15 of the estrous cycle. Non-pregnant Bos taurus beef cows (n = 23) were exposed to a pre-synchronization step followed by the 7-d CO-Synch estrus synchronization protocol. On days -10, -3,0 (exogenously induced ovulation),7 and 14, transrectal ultrasonography was performed to evaluate ovarian structures, ensure synchrony, and determine the side of ovulation. Estrotect patches were applied on day -3, and cows with an activated patch (rubbed > 50%) on day 0 were considered to have displayed heat. Cows were harvested on day 15 and individual swabs were collected from each horn using aseptic techniques. DNA was extracted and the entire (V1-V9 hypervariable regions)16s rRNA gene was sequenced. Sequences were analyzed using the QIIME2 Pipeline. Burkholderiaceae, Chitinophagaceae, Rikenellaceae, Burkholderia, Rikenellaceae RC9 gut group, Lachnospiraceae AC2044 group, Vibrionimonas, Prevotellaceae UCG-001, and Rikenellaceae dgA-11 gut group abundances differed significantly (P < 0.05) in cows that exhibited estrus compared with non-estrual cows. In conclusion, there were significant differences in the composition of the microbial community between cows that exhibited estrus and non-estrual cows. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the uterine microbiota composition of cows on day 15 of the estrous cycle. Non-pregnant Bos taurus beef cows (n = 23) were exposed to a pre-synchronization step followed by the 7-d CO-Synch estrus synchronization protocol. On days -10, -3, 0 (exogenously induced ovulation), 7 and 14, transrectal ultrasonography was performed to evaluate ovarian structures, ensure synchrony, and determine the side of ovulation. Cows were harvested on day 15 and individual swabs were collected from each uterine horn using aseptic techniques. DNA was extracted and the entire (V1-V9 hypervariable regions) 16s rRNA gene was sequenced. Sequences were analyzed using the QIIME2 Pipeline. Across all samples, 22 phyla, 130 families, 215 genera, and 90 different species were identified. Butyrivibrio, Bacteroidales RF16 group, Clostridia_UCG-014, and Moraxellaceae, had different (P < 0.05) relative abundances in the ipsilateral compared with contralateral horns, whereas Proteobacteria, Acinetobacter, Bradyrhizobium, Lachnospiraceae FCS020 group, Nanoarchaeota, Woesearchaeales, and Prevotellaceae YAB2003 group tended (P < 0.10) to differ between ipsilateral and contralateral horns. In conclusion, there were significant differences in the composition of the microbial community of the ipsilateral and contralateral horn of cows on day 15 of the estrous cycle. [ABSTRACT FROM AUTHOR]

Shifts from commensal bacteria (for example, Lactobacillus in the phylum Firmicutes) within the reproductive tract have been associated with changes in local reproductive immune responses and decreased fertility in humans. The objective of this study was to characterize the microbiome and cytokine concentrations before artificial insemination (AI) in vaginal and uterine flushes from postpartum beef cows. Twenty Bos indicus-influenced beef cows (approximately 60 d postpartum and free of reproductive, health, or physical issues) were enrolled. The B. indicus prostaglandin (PG) 5-d + controlled intervaginal drug-releasing estrus synchronization protocol was initiated on day -8 of the study with timed AI on d0. Blood samples were collected on days -3, -1, and 28 via coccygeal venipuncture. Vaginal and uterine flushes were collected on days -3 and -1. Based on days 28 pregnancy status determined by transrectal ultrasonography, cows were identified as either Open (n = 13) or Pregnant (n = 7). Bacterial community analyses were conducted targeting the V4 hypervariable region of the 16S rRNA gene. Cytokine analyses were performed using the RayBiotech Quantibody Bovine Cytokine Array Q1 and MyBioSource ELISA kits per the manufacturer's instructions. Statistical analyses for bacteria relative abundance were conducted using PROC NPAR1WAY and for cytokine concentrations using PROC GLM in SAS 9.4. Uterine concentrations of interferon γ, interleukin (IL)1α, and IL21 were greater in Open than in Pregnant cows (P < 0.05). Regardless of pregnancy status, uterine IL13 increased from days -3 to -1 (9.76 vs. 39.48 ± 9.28 pg/mL, respectively; P < 0.05). Uterine relative abundance of the phylum Firmicutes decreased from days -3 to -1 in Open cows (60.4% ± 0.9% vs. 48.5% ± 3.2%; P = 0.004). In Open cows, the genus Blautia decreased in relative abundance within the uterus from days -3 to -1 (2.1% ± 0.2% vs. 0.9% ± 0.1%; P = 0.002). Uterine relative abundance of the phylum Tenericutes increased from days -3 to -1 in Pregnant cows (1.0% ± 0.1% vs. 7.6% ± 4.1%; P = 0.002). In Pregnant cows, the genus Ureaplasma tended to increase within the uterus from days -3 to -1 (0.08% ± 0.06% vs. 7.3% ± 4.1%; P = 0.054). These findings suggest a distinct difference in the reproductive microbiome and cytokine profiles before AI for resulting Open vs. Pregnant cows., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Direct selection for uterine capacity (UC) increased the number of live pigs born. A method to indirectly estimate UC in developing gilts is needed for this trait to be incorporated into commercial selection strategies. We tested the hypothesis that selection for UC alters phenotypic characteristics of the reproductive tract of prepubertal gilts and that these changes could be estimated in live animals using transrectal ultrasound (TRU). Gilts from lines selected for UC and a randomly selected control (CO) line were submitted for TRU at 130, 150, or 170 d of age and harvested 24 h later (n = 10 gilts/line per age). Diameter of the uterine horn was measured (2 to 4 measurements per animal) at TRU. At harvest, measurements of the ovary (height, width, length, weight, and number of visible follicles >1 mm) and uterine horn (weight, length, diameter, and endometrial diameter) were taken. There was no line × age interaction for any of the traits. All ovarian traits increased (P < 0.03) with age. Weight and length of the uterine horn was not different at 130 or 150 d but were increased (P < 0.01) at 170 d of age. Diameter of the uterine horn tended (P = 0.06) to be increased at 170 d compared with 130 or 150 d, but age did not affect (P = 0.38) endometrial diameter. Ovarian weight and width were increased (P < 0.01) and ovarian length and height tended (P = 0.07) to be greater for UC than CO gilts, but the number of visible follicles did not differ. The UC gilts had increased (P < 0.02) weight of uterine horns, which tended (P = 0.09) to be longer than in the CO gilts. Diameter of the uterine horn and the endometrium were greater (P < 0.01) for UC gilts than for CO gilts. Uterine horn diameter measured with TRU was not affected by age or line and was not highly correlated with any of the measured traits. Selection for increased UC results in larger ovaries and uterine horns, but TRU was not useful for estimating these traits in gilts of the age studied. [ABSTRACT FROM AUTHOR]

At birth, the newborn mammal under-goes a transition from a sterile uterine environment with a constant nutrient supply, to a microbe-rich envi-ronment with intermittent oral intake of complex milk nutrients via the gastrointestinal tract (GIT). These functional challenges partly explain the relatively high morbidity and mortality of neonates. Preterm birth interrupts prenatal organ maturation, including that of the GIT, and increases disease risk. Exemplary is nec-rotizing enterocolitis (NEC), which is associated close-ly with GIT immaturity, enteral feeding, and bacterial colonization. Infants with NEC may require resection of the necrotic parts of the intestine, leading to short bowel syndrome (SBS), characterized by reduced digestive capacity, fluid loss, and dependency on par-enteral nutrition. This review presents the preterm pig as a translational model in pediatric gastroenterology that has provided new insights into important pediat- ric diseases such as NEC and SBS. We describe pro-tocols for delivery, care, and handling of preterm pigs, and show how the immature GIT responds to delivery method and different nutritional and therapeutic inter-ventions. The preterm pig may also provide a sensitive model for postnatal adaptation of weak term piglets showing high mortality. Attributes of the preterm pig model include close similarities with pretenn infants in body size, organ development, and many clinical features, thereby providing a translational advantage relative to rodent models of GIT immaturity. On the other hand, the need for a sow surgical facility, a pig-let intensive care unit, and clinically trained personnel may limit widespread use of preterm pigs. Studies on organ adaptation in preterm pigs help to identify the physiological basis of neonatal survival for hypersensi-tive newborns and aid in defining the optimal diet and rearing conditions during the critical neonatal period. [ABSTRACT FROM AUTHOR]

The 2012 Triennial Reproduction Symposium (TRS), "Impediments to Fertility in Domestic Animals," was held immediately before the Joint Annual Meeting of the American Society of Animal Science, American Dairy Science Association, Canadian Society of Animal Science, Western Section of the American Society of Animal Science, and the Asociación Mexicana de Producción Animal in Phoenix, AZ, in July, 2012. The theme of the symposium highlighted key impediments or opportunities in the process of creating a pregnancy, beginning with male and female gametes and ending with a viable fetus. The 2012 TRS was designed to focus on areas of current and exciting investigation across a variety of species and to include 8 presentations from a mix of established and early-career scientists. The TRS was also the venue for presentation of the 2012 L. E. Casida Award for Graduate Education; the recipient was R. D. Randel (Texas A&M University). The symposium provided an excellent opportunity for reproductive biologists to consider the broad spectrum of factors that limit fertility in domestic species and contemplate the current status of knowledge relative to several of the significant obstacles to pregnancy. [ABSTRACT FROM AUTHOR]

Pregnancy failure in livestock can result from failure to fertilize the oocyte or embryonic loss during gestation. The focus of this review is on cattle and factors affecting and mechanisms related to uterine insufficiency forpregnancy. A variety of factors contribute to embryonic loss and it may be exacerbated in certain animals, such as high-producing lactating dairy cows, and in some cattle in which estrous synchronization and timed Al was performed, due to reduced concentrations of reproductive steroids. Recent research in beef cattle induced to ovulate immature follicles and in lactating dairy cows indicates that deficient uterine function is a major factor responsible for infertility in these animals. Failure to provide adequate concentrations of estradiol before ovulation results in prolonged effects on expression and localization of uterine genes and proteins that participate in regulating uterine functions during early gestation. Furthermore, progesterone concentrations during early gestation affect embryonic growth, interferontau production, and uterine function. Therefore, an inadequate uterine environment induced by insufficient steroid concentrations before and after ovulation could cause early embryonic death either by failing to provide an adequate uterine environment for recognition of embryo signaling, adhesion, and implantation or by failing to support appropriate embryonic growth, which could lead to decreased conceptus size and failed maternal recognition of pregnancy. [ABSTRACT FROM AUTHOR]

Three experiments were designed to evaluate methods to optimize the use of sex-sorted sperm in timed AI (TAI) programs for suckled beef cows. In all 3 experiments, suckled Bos indicus cows were synchronized using an intravaginal progesterone (P4) device during 8 d and a 2.0-mg injection of intramuscular estradiol benzoate (EB) at device insertion. The females received PG and eCG (300IU) at P4 device removal and 1.0 mg of EB 24 h later. The cows were inseminated 60 to 64 h after P4 device withdrawal. All cows had their ovaries scanned by transrectal ultrasound at TAI to indentify and to measure the largest follicle (LF) present. In Exp. 1, a total of 853 cows had their LF classified as <9 mm or ≥9 mm at the time of TAI; these cows were then randomly assigned to 4 groups according to their LF diameter (<9 mm or ≥9 mm) and the type of sperm used (sex-sorted or non-sex-sorted). There was an interaction (P = 0.02) between the type of sperm and LF diameter beginning at TAI[non-sex-sorted ≥9 mm = 58.9%a (126/214); non-sex-sorted ≥9 mm = 49.5%b (106/214);sex-sorted ≥9 mm = 56.8%ab (134/236); and sex-sorted <9 mm = 31.2%c (59/189), means without a common superscript differ; P < 0.05]. In Exp. 2, suckled cows (n = 491) were classified immediately before TAI as having displayed estrus or not (estrus or no estrus) between P4 device removal and TAI. These cows were randomly assigned to 4 groups according to the occurrence of estrus and the type of sperm (sex-sorted or non-sex-sorted). There were effects of the occurrence of estrus (P = 0.0003) and the type of sperm (P = 0.05) on pregnancy per AI [P/AI; no estrus, non-sex-sorted = 43.6% (27/62); estrus, non-sex-sorted = 58.5%; (107/183); no estrus, sex-sorted = 33.9% (21/62), and estrus, sex-sorted = 50.0% (92/184)]; however, no interaction between the occurrence of estrus and type of sperm was observed (P = 0.87). In Exp. 3, a total of 200 suckled cows presenting LF ≥9 mm at TAI were randomly assigned to receive sex-sorted sperm deposited into the uterine body (n = 100) or into the uterine horn ipsilateral to the recorded LF (n = 100). No effect of deeper AI on P/AI was found (P = 0.57). Therefore, the LF diameter at TAI and the occurrence of estrus can be used as selection criteria to identify cows with greater odds of pregnancy to receive sex-sorted sperm in TAI programs. In addition, performing TAI with sex-sorted sperm deeper into the uterus did not alter the pregnancy results. [ABSTRACT FROM AUTHOR]

The association of the 2464G > A SNP found in the promoter region of the rabbit progesterone receptor gene with progesterone receptor (PR) expression was evaluated by Western blot analysis. This SNP was associated with 2 lines divergently selected for uterine capacity, the high line selected to increase uterine capacity and the low line selected to decrease uterine capacity. Two progesterone isoforms were obtained using a commercial monoclonal antibody: the PR-B isoform described previously in rabbits, and the PR-A isoform, not described previously in rabbits. The GG genotype, the genotype more frequent in the high line, showed less PR-B and PR-A expression than the AA genotype in the oviduct (GG/AAPR-B = 0.81 and GG/AAPR-A = 0.73) and uterus (around 0.70 in both isoforms). The GA genotype showed similar PR-A expression in both tissues and also similar PR-B expression in the oviduct to the GG genotype. Conversely, the GG genotype showed less PR-B expression than the GA genotype in the uterus (GG/GAPR-B = 0.79). Similar expression of both PR isoforms was found in the uterus at d 2 and 3 of gestation; meanwhile, an increase of both isoforms was observed in the oviduct. Similar PR-A expression was observed in the ampulla and isthmus; meanwhile, the PR-B expression in the isthmus was double that in the ampulla. [ABSTRACT FROM AUTHOR]

Dietary constituents can affect cow acid-base physiology and uterine pH. Dietary cation- anion difference (DCAD) has been shown to affect cow acid-base physiology, but the effect on uterine pH has not been demonstrated. The objective of this work was to determine if DCAD [(Na + K + 0.15Ca + 0.15Mg) - (Cl + 0.60S + 0.50P)] could affect cow DM1, acid- base physiology, and uterine pH, and second, to determine if dietary supplements could alleviate any negative effects of DCAD on these variables. In Exp. 1, 21 cows were utilized to determine the effect of a negative DCAD (-0.9 mEq/100 g of DM; low-DCAD) or positive DCAD (+25.0 mEq/100 g of DM; high-DCAD) diet on cow BW, DM1, and pH of blood, urine, and uterine flush fluid. In Exp. 2, 21 cows were randomly allotted to 1 of 3 treatments: control (-3.1 mEq/100 g of DM), molasses (+2.9 mEq/100 g of DM), or molasses+buffer (+25.8 mEq/100 g of DM) to determine if supplemental liquid molasses or liquid molasses with a buffer could alleviate the effects of a negative DCAD, forage-based diet. Cows were individually fed their respective diets for 42 d in both experiments. Cow BW, blood, urine, and uterine flush were collected on d 0, 21, and 42 during both experiments. Cow ADG was not different (P = 0.71) in Exp. 1 or Exp. 2 (P = 0.47). Hay DMI did not differ (P < 0.70) between high-DCAD and low-DCAD cows before d 28, but was greater (P < 0.001) for high- DCAD cows after d 28 in Exp. 1. In Exp. 2, mean hay DM1 did not differ (P = 0.39) among treatments. In Exp. 1, a treatment x day interaction (P < 0.05) was apparent for blood, pH, base excess, bicarbonate, pCO2, and urine pH. Blood gas and pH measures peaked on d 21 for high-DCAD and declined from d 0 to 42 in low-DCAD cows. High-DCAD cows had greater (P = 0.08) uterine flush pH compared with low-DCAD cows. In contrast, during Exp. 2 there were no differences (P > 0.14) among treatments for blood, pH, base excess, pCO2, or uterine flush pH. Urine pH exhibited a treatment x day interaction (P < 0.0001). On d 21 molasses supplemented cow urine pH was greater (P < 0.0001) than control cows, whereas on d 42 molasses+buffer had greater (P = 0.01) urine pH compared with control and molasses cows. Dietary cation-anion difference and the use of molasses-based supplements had minimal effect on forage-fed beef cow DMI. However, DCAD has the capacity to alter forage-fed beef cow acid-base physiology and potentially affect uterine physiology. [ABSTRACT FROM AUTHOR]

Protein supplementation to replacement heifers is utilized to reach targeted body weights, which may affect the animal's gut and reproductive microbiomes and potentially impact breeding outcomes. The objective of the study was to evaluate the effects of protein supplementation on the ruminal and uterine bacterial communities of developing heifers. Thirty-nine pre-pubertal commercial Angus heifers were blocked by body weight (BW) and randomly assigned to one of three supplementation groups: 10% crude protein (CP), 20% CP, or 40% CP. Supplements were provided four times weekly for 140d. Blood and BW were taken every 14d to monitor development. Every 56d, uterine flushes and rumen content were collected for bacterial identification. Uterine flushes were collected via 20 mL sterile saline flushed through a Foley catheter, and rumen content by esophageal tubing. Bacterial DNA was extracted and amplified targeting the V1-V3 region of the 16S rRNA gene. Microbiome analyses were performed in R 4.1 with dada2 and phyloseq packages. Statistical analyses were performed in R and SAS 9.4. The GLIMMIX procedure was used including fixed effects of protein, month, and pubertal status. Random effects included BW, interaction of BW and protein, and heifer within the interaction, with repeated measures of month. Alpha diversity differed by month in the rumen, and by month and pubertal status in the uterus (P < 0.05). Bray Curtis analyses indicated clustering by month and pubertal status (P < 0.001) in the uterus, and by month in the rumen (P < 0.001). Multiple uterine and ruminal bacteria abundances differed over time and by protein supplementation and pubertal status (P < 0.05). The impact of pubertal status and month of development may indicate maturation of the uterine bacterial communities through development. Protein supplementation affecting the uterine bacterial communities may provide opportunity to manipulate the uterine microbiome, potentially affecting future reproductive success. [ABSTRACT FROM AUTHOR]

Posttranscriptional gene regulation plays a vital role in male and female germ cell function, but our understanding of this regulatory process in somatic cells and its effect on reproductive tissue development and function is not understood. In mammalian cells, microRNA (miRNA) are key posttranscriptional regulators and function by modulating translation or degradation of their target mRNA. Mature miRNA are synthesized through a multi-step process that concludes with the cleavage of stem-loop pre-miRNA by the RNase III enzyme, Dicer1. To determine the extent of miRNA regulation and establish a baseline, miRNA profiling has indicated the presence of large numbers of miRNA within reproductive tissues and cells. Moreover, several studies have indicated that miRNA expression in reproductive tissues varies in response to pituitary and gonadal hormones. To understand the role that miRNA-mediated posttranscriptional gene regulation plays in female reproduction, a global Dicer1 hypomorph mouse and several tissue-specific Dicer1 knockout mice have been studied. Interestingly, when Dicer1 expression is decreased in reproductive tissues or cells, the females are infertile. This review discusses all the work regarding miRNA regulation within the mammalian female reproductive system published to date. [ABSTRACT FROM AUTHOR]

Progesterone and estrogens play key roles in regulating various physiological phenomena related to normal growth, development, and reproduction of domestic animals. This review focuses on the mechanisms by which progesterone and estrogens regulate the reproductive processes in these animals. The majority of research on the actions of progesterone and estrogens on the reproductive systems of cattle, sheep, and pigs has been genomic in nature and represents attempts to better understand how these steroids regulate gene expression. Results of recent research suggest that progesterone and estrogens can alter target cell responses nongenomically via membrane receptors. The characteristics of membrane receptors for progesterone and estrogen in various cell types are described and the intracellular signal pathways defined. Estrogens acting via membrane receptors can suppress LH secretion by gonadotropes and stimulate rapid increases in uterine blood flow. Progesterone acting via a membrane receptor has been shown to inhibit binding of oxytocin to oxytocin receptors in isolated endometrial plasma membranes and stimulate capacitation of spermatozoa. Results of research suggest that progesterone and estrogens can act nongenomically to alter target cell responses in domestic animals. The biological implications of this mode of action in these animals are discussed. [ABSTRACT FROM AUTHOR]

The experimental objectives were to evaluate the influence of supplemental high-linoleate safflower seeds on fatty acid concentrations in plasma, medial basal hypothalamus, uterine tissues, and serum 13,14-dihydro-15-keto PGF2α metabolite (PGFM) in primiparous beef cows during early lactation. Beginning 1 d postpartum, 18 primiparous, crossbred beef cows (411 ± 24.3 kg of BW) were fed foxtail millet hay at 1.68% of BW (DM basis) and either a low-fat supplement (control: 63.7% cracked corn; 33.4% safflower seed meal; and 2.9% liquid molasses; DM basis) at 0.35% of BW (n =9) or a supplement (linoleate) containing 95.3% cracked high-linoleate (79% 18:2n-6) safflower seeds and 4.7% liquid molasses (DM basis) at 0.23% of BW (n = 9). Diets were formulated to be isonitrogenous and isocaloric. The linole ate diet contained 5.4% of DM1 as fat vs. 1.2% for control. Beginning 1 d postpartum, cattle were bled every 3 d for collection of serum and plasma. Cattle were slaughtered at 37±3 d postpartum for collection of the medial basal hypothalamus, myometrium, endometrium, caruncular tissue, intercaruncular tissue, and oviduct. Feeding linoleate increased (P = 0.001) plasma concentrations of 18:2n-6, 18:2cis-9 trans-11 and total unsaturated fatty acids; however, 18:1trans-11 did not differ (P = 0.19) between treatments. Concentrations of 20:5n-3 in the medial basal hypothalamus tended (P = 0.10) to be greater for cattle fed linoleate. Concentrations of fatty acids in the oviduct were greater (P < 0.05) than in other uterine tissues. Cows fed linoleate had greater (P = 0.05) concentrations of 18:3n-3 in the endometrium and less (P = 0.06) 18:2cis-9 trans-11 in the myometrium than cows fed the control. Supplemental fat increased (dietary treatment x day postpartum, P = 0.01) concentrations of PGFM in serum more in linoleate than control cows from d 3 to 9 postpartum. Lipid supplementation early in the postpartum period altered the fatty acid composition of medial basal hypothalamus, uterine tissue, and serum concentrations of PGFM. The most novel observation was that the oviduct appeared to be the most sensitive tissue to additional dietary linoleic acid, which could potentially influence fertility. [ABSTRACT FROM AUTHOR]

Seminal fluid contains potent signaling agents that influence female reproductive physiology to improve the chances of conception and pregnancy success. Cytokines and prostaglandins synthesized in the male accessory glands are transferred to the female at insemination, where they bind to receptors on target cells in the cervix and uterus, activating changes in gene expression that lead to modifications in structure and function of the female tissues. The consequences are increased sperm survival and fertilization rates, conditioning of the female immune response to tolerate semen and the conceptus, and molecular and cellular changes in the endometrium that facilitate embryo development and implantation. Male-female tract signaling occurs in rodents, livestock animals, and all other mammals examined thus far, including humans. In mice, the key signaling moieties in seminal plasma are identified as members of the transforming growth factor-β family. Recent studies indicate a similar signaling function for boar factors in the pig, whereby the sperm and plasma fractions of seminal fluid appear to synergize in activating an inflammatory response and downstream changes in the female tract after insemination. Seminal plasma elicits endometrial changes, with induction of proinflammatory cytokines and cyclooxygenase-2, causing recruitment of macrophages and dendritic cells. Sperm contribute by interacting with seminal plasma factors to modulate neutrophil influx into the luminal cavity. The cascade of changes in local leukocyte populations and cytokine synthesis persists throughout the preimplantation period. Exposure to seminal fluid alters the dynamics of preimplantation embryo development, with an increase in the number of fertilized oocytes attaining the viable blastocyst stage. There is also evidence that seminal factors influence the timing of ovulation, corpus luteum development, and progesterone synthesis. Insight into the molecular basis of seminal fluid signaling in the female reproductive tract may inform new interventions and management practices to ensure maximal fertility and reduce embryo mortality in pigs and, potentially, other livestock species. [ABSTRACT FROM AUTHOR]

We hypothesized that the ability of the fetus to alter nutrient shunting and organ growth might be associated with uterine capacity. White crossbred gilts from a randomly selected control line, a line selected for ovulation rate, and a line selected for uterine capacity (UC) were unilaterally hysterectomized-ovariectomized at 160 d of age, mated at estrus, and slaughtered at 45, 65, 85, and 105 d of gestation (9 to 18 gilts for each line × day combination). Analysis of the data revealed that heart weights and fetal weights were decreased in the ovulation rate line. No significant differences were obtained in fetal, placental, or fetal organ weights between the control and UC lines. Allometric growth of organs was assessed by examination of the slopes of the relationships between fetal weights and fetal organ weights after natural log transformation. Only the relative growth of the liver differed between selection lines and was greater (P = 0.01) in the UC compared with the control line during early pregnancy (d 45 and 65). Allometric growth of the fetal brain, liver, and heart differed with day of gestation. A brain-sparing effect was greater (P < 0.01) on d 85 and 105 compared with d 45 and 65. By contrast, a heart-sparing effect was present during early gestation and disappeared in later gestation. Fetal liver weights were hypersensitive to differences in fetal weights on d 45, possibly associated with placental effects on fetal liver weight. Fetal spleen weights were proportional to fetal weights throughout gestation. These results indicate that selection for ovulation rate decreased total fetal and fetal heart weights, and that selection for UC altered the relationship between total fetal and fetal liver weights during early gestation. Results further indicate significant changes in allometric growth of organs during gestation. [ABSTRACT FROM AUTHOR]

The soybean phytoestrogen genistein has a range of estrogenic actions demonstrated in various species; however, only limited research has been done to investigate its effects in swine. The objective of this study was to characterize the effects of a graded dose of genistein on estrogen-sensitive uterine and cervical tissues in ovariectomized guts. Thirty-four postpubertal gilts were ovariectomized and assigned randomly to 1 of 6 treatment groups 15 d postovariectomy. Treatment groups received vehicle, estradiol benzoate (2 mg/d), or genistein (50, 100, 200, or 400 mg/d) via intramuscular injection at 12-h intervals for 10 d. Following the treatment period, guts were euthanized, and uterine and cervical tissues were collected and processed for chemical or histological analysis. Uterine and cervical tissue mass, as indicated by wet, dry, and protein weights and total DNA content (expressed per 100 kg of BW), increased as the dosage of genistein increased (P < 0.001 for each regression). Uterine and cervical wet weights were increased by a dosage of 200 mg of genistein/d (P < 0.001 and P < 0.01, respectively) but not by 100 mg of genistein/d (P = 0.38 and P = 0.14, respectively) compared with those of control gilts. Height of epithelial cells lining the uterine glands and the lumen of uterus and cervix increased when guts were treated with estradiol benzoate or 400 mg of genistein/d (P < 0.01). When the guts were treated with estradiol benzoate or 400 mg of genistein/d, immunohistochemical staining demonstrated an increase in the percentage of cells that stained positive for progesterone receptor in the uterine glands and in the cells lining the vaginal cervix (P < 0.05). In guts treated with 400 mg of genistein/d, the percentage of cells stained positive for proliferating cell nuclear antigen increased in the epithelium of the uterine glands, uterine lumen, and vaginal cervix (P < 0.05). Tissue growth was stimulated by genistein in a dosage-dependent manner, although no dosage of genistein induced a response as great as that of estradiol benzoate. Estrogen-sensitive tissues of the ovariectomized gilt, such as the cervix and uterus, are affected by injection of large dosages of the phytoestrogen genistein. The sensitivity of the uterus of the gilt to estrogenic substances makes it a potential model to examine the impact of environmental endocrine modulators on reproductive tissues. [ABSTRACT FROM AUTHOR]

Presents abstracts of studies on the effect of stress and inflammation on animal performance. "Performance of Gifts Housed Individually in Stalls or In Groups in Pens During the First 30 d Post-Mating," by M.J. Estienne, A.F. Harper and J.W. Knight; "Effects of Stress and Genotype on Immune and Cortisol Measures in Pigs," by M.A. Sutherland, S.R. Niekamp, S.L. Rodriguez-Zas and J.L. Salak-Johnson; "The Use of a Hens' Odorant Analogue to Control Stress Consequences in Broilers," by I. Madec, J.F. Gabarrou, A. Bruneau, L. Bougrat, D. Saffray, B. Silliart and P. Pageat.

Presents abstracts of several articles on the physiology and endocrinology of female animal reproduction. "Distinct Steroidal Regulation of mRNAs for Aromatase and Gonadotropin Receptors in Bovine Granulosa Cells," by W. X. Luo and M. C. Wiltbank; "The Expression and Localisation of Angiogenic Growth Factors in the Porcine Corpus Luteum," by R. S. Robinson, A. J. Hammond, G. E. Mann and M. G. Hunter; "What Regulates Ovine Placental Steroidogenesis?," by C. Weems and C. Yin; "Observed Frequency of Monozygotic Twinning in Lactating Holstein Cows," by N. Silva Del Rio, B. W. Kirkpatrick and P. M. Fricke.

All mammalian uteri contain endometrial glands that synthesize or transport and secrete substances essential for survival and development of the conceptus (embryo/fetus and associated extraembryonic membranes). The ovine uterine gland knockout ewe model supports a primary role for endometrial glands and, by default, their secretions as essential for conceptus survival and development during the peri-implantation period of pregnancy. Endometrial adenogenesis, the process whereby glands develop in the uterus, is primarily a postnatal event in domestic and laboratory animals, as well as in humans. Endometrial adenogenesis involves differentiation and budding of glandular epithelium from lumenal epithelium, followed by invagination and extensive tubular coiling and branching morphogenesis throughout uterine stroma to the myometrium. In sheep, pituitary prolactin acting on prolactin receptors expressed by uterine glandular epithelium regulates endometrial adenogenesis. In contrast, expression and functional activation of estrogen receptor α in the uterus is a primary regulator of endometrial adenogenesis in the pig. In adult sheep and pigs, extensive endometrial gland hyperplasia and hypertrophy occur during gestation, presumably to provide increasing histotrophic support for conceptus growth and development. A servomechanism has been proposed in sheep and pigs to regulate endometrial gland development and differentiated function during pregnancy that involves sequential actions of ovarian steroid hormones, pregnancy recognition signals, and lactogenic hormones from the pituitary and/or placenta. The fact that disruption of uterine development during critical organizational periods can alter the functional capacity and embryotrophic potential of the adult uterus reinforces the importance of understanding uterine developmental biology. Defects in endometrial gland morphogenesis during uterine growth and development may cause the unexplained, high rates of peri-implantation embryonic loss in domestic animals and humans. Knowledge of the basic mechanisms regulating uterine development is expected to suggest means to increase uterine capacity, litter size, and neonatal survival, as well as ameliorate certain types of infertility. [ABSTRACT FROM AUTHOR]