Steroidal regulation of uterine immune defenses

Exploring uterine inflammation in postpartum primiparous precocious and conventional and multiparous Bos indicus beef cows

This study aimed to compare the postpartum uterine dynamics of primiparous precocious (PP), primiparous conventional (PC) and multiparous conventional (MC) Bos indicus beef cows. For this purpose, PP (n = 8), PC (n = 18) and MC (n = 12) cows were enrolled in this study. These cows were evaluated at 20 and 10 days prepartum and weekly from parturition to 42 days postpartum (DPP). During this period, body weight (BW), subcutaneous fat thickness (SFT) and serum concentrations of glucose, β-hydroxybutyrate, albumin and haptoglobin were measured. Proportion of polymorphonuclear (PMN) cells, and abundance of mRNA transcripts of genes involved in uterine inflammation and uterine health were evaluated. The PP cows had lower (p < .05) BW and SFT than that for PC and MC cows during the study period. The serum concentration of albumin after 35 DPP was lower (p < .05) in PP cows. The PP cows had the highest proportion of PMN on 28 and 35 DPP compared to PC and MC cows. The relative mRNA abundance of IL-1β and IL-8 increased after 21 DPP in PP cows compared to the other groups. The PC had the highest, MC had an intermediate, and PP cows had the lowest relative abundance of IL10 mRNA. Overall, these findings indicated that uterine inflammation was more pronounced in PP cows. Moreover, based on the proportion of PMN and abundance of transcripts associated with inflammation in the uterus, PP cows may require a longer period to recover their uterine health after calving.

Uterine Inflammation Changes the Expression of Cholinergic Neurotransmitters and Decreases the Population of AChE-Positive, Uterus-Innervating Neurons in the Paracervical Ganglion of Sexually Mature Gilts

Simple Summary

Endometritis, both with non-infectious and infectious backgrounds, is one of the most prevalent pathological states among domestic animals. In animals, it generates severe economic problems, including lowered reproductive indices and rising medical treatment costs, and in women, it might lead to severe fertility impairment. In order to determine how the autonomic nervous system responds to such a pathological state, an experimental group of pigs were treated with Escherichia coli injection into the uterine horns, and several ganglions responsible for innervation of this organ were examined, including the paracervical ganglion located on both sides of the broad ligament of the uterus. The results clearly showed a strong impact of the inflammation on the chemical coding of neurons, some even synthesizing neurotransmitters de novo such as the GAL-expressing perikarya. Additionally, applied injections decreased the number of parasympathetic, acetylcholinesterase-expressing neurons implying the importance of the cholinergic population to keep the inflammation under control. The obtained data serve as a basis for the future implementation of modern treatment and enhancements in animal breeding.

Abstract

The focus of this study was based on examining the impact of endometritis on the chemical coding of the paracervical ganglion (PCG) perikaryal populations supplying pig uterus. Four weeks after the injection of Fast Blue retrograde tracer into uterine horns, either the Escherichia coli (E. coli) suspension or saline solution was applied to both horns. Laparotomy treatment was performed for the control group. Uterine cervices containing PCG were extracted on the eighth day after previous treatments. Subsequent macroscopic and histopathologic examinations acknowledged the severe form of acute endometritis in the E. coli-treated gilts, whereas double-labeling immunofluorescence procedures allowed changes to be analyzed in the PCG perikaryal populations coded with vesicular acetylcholine transporter (VAChT) and/or somatostatin (SOM), vasoactive intestinal polypeptide (VIP), a neuronal isoform of nitric oxide synthase (nNOS), galanin (GAL). The acetylcholinesterase (AChE) detection method was used to check for the presence and changes in the expression of this enzyme and further confirm the presence of cholinergic perikarya in PCG. Treatment with E. coli resulted in an increase in VAChT+/VIP+, VAChT+/VIP−, VAChT+/SOM+, VAChT+/SOM−, VAChT+/GAL− and VAChT+/nNOS− PCG uterine perikarya. An additional increase was noted in the non-cholinergic VIP-, SOM- and nNOS-immunopositive populations, as well as a decrease in the number of cholinergic nNOS-positive perikarya. Moreover, the population of cholinergic GAL-expressing perikarya that appeared in the E. coli-injected gilts and E. coli injections lowered the number of AChE-positive perikarya. The neurochemical characteristics of the cholinergic uterine perikarya of the PCG were altered and influenced by the pathological state (inflammation of the uterus). These results may indicate the additional influence of such a state on the functioning of this organ.

Anti-inflammatory effects of progesterone through NF-κB and MAPK pathway in lipopolysaccharide- or Escherichia coli-stimulated bovine endometrial stromal cells

Postpartum uterine infection in dairy cows is commonly caused by pathogenic bacteria such as Escherichia coli (E. coli). Progesterone elicits immunosuppressive function within bovine endometrium, and has been suggested to be related to postpartum uterine infection. Endometrial stroma is exposed to bacteria due to the disruption of epithelium during parturition, but the effect and mechanism of progesterone on innate immune response of stromal cells has not been reported. This study evaluated the impact of progesterone on inflammatory response of primary endometrial stromal cells stimulated by lipopolysaccharide or heat-killed E. coli. Quantitative PCR analysis revealed that progesterone repressed mRNA induction of IL1B, IL6, TNF, CXCL8, NOS2, and PTGS2 in stromal cells in response to lipopolysaccharide or E. coli challenge. Consistently, Western blot and immunofluorescence staining results showed that progesterone suppressed lipopolysaccharide- or E. coli-induced MAPK and NF-κB activations characterized with decreased phosphorylations of ERK1/2, JNK, P38, IκBα, and P65, and inhibition of P65 nuclear translocation. In unstimulated stromal cells, progesterone alone did not affect the mRNA transcription for IL6, TNF, CXCL8, NOS2, and PTGS2, and the signaling cascade of MAPK and NF-κB, but decreased IL1B mRNA expression. These results revealed that the anti-inflammatory effect of progesterone in lipopolysaccharide- or E. coli-challenged endometrial stromal cells was probably mediated through MAPK and NF-κB pathways.

Nutritional restriction during the peri-conceptional period alters the myometrial transcriptome during the peri-implantation period

This study hypothesized that female peri-conceptional undernutrition evokes transcriptomic alterations in the pig myometrium during the peri-implantation period. Myometrium was collected on days 15-16 of pregnancy from pigs fed a normal- (n = 4) or restricted-diet (n = 4) from conception until day 9th of pregnancy, and the transcriptomic profiles of the tissue were compared using Porcine (V2) Expression Microarrays 4 × 44 K. In restricted diet-fed pigs, 1021 differentially expressed genes (DEGs) with fold change ≥ 1.5, P ≤ 0.05 were revealed, and 708 of them were up-regulated. Based on the count score, the top within GOs was GO cellular components "extracellular exosome", and the top KEGG pathway was the metabolic pathway. Ten selected DEGs, i.e. hydroxysteroid (17β) dehydrogenase 8, cyclooxygenase 2, prostaglandin F receptor, progesterone receptor membrane component 1, progesterone receptor membrane component 2, annexin A2, homeobox A10, S-phase cyclin A-associated protein in the ER, SRC proto-oncogene, non-receptor tyrosine kinase, and proliferating cell nuclear antigen were conducted through qPCR to validate microarray data. In conclusion, dietary restriction during the peri-conceptional period causes alterations in the expression of genes encoding proteins involved i.a. in the endocrine activity of the myometrium, embryo-maternal interactions, and mechanisms regulating cell cycle and proliferation.

Uterine Involution of Mares Supplemented with Dietary Algae-Derived Omega-3 Fatty Acids During the Peripartum Period

Different approaches have been used to improve conception rates at foal heat. Omega-3 fatty acids family and derivatives have improved reproductive efficiency in ruminants, but literature lacks studies evaluating these components on equines. The objective of this study was to evaluate effects of mare dietary supplementation with microalgae rich in docosahexaenoic acid (DHA) during peripartum on follicular dynamics and uterine involution in early post-partum. Eighteen pregnant mares, no particular breed, 410 ± 39.5 kg body weight (BW), and 7.83 ± 2.01 yr old were used. Mares were randomly assigned to control (CONT) or supplementation with microalgae rich in DHA at 0.06 g/kg BW (ALG). Treatments were supplied from 90 d prior to expected foaling date until 7 d after first ovulation. Reproductive evaluations were performed during early post-partum until 7 d after first ovulation through rectal palpation and ultrasonography of the following parameters: uterine and endometrium diameters, intrauterine fluid (IUF), uterine echogenicity, uterus tone, and follicular dynamics. Endometrial cells samples were collected to assess mRNA expression of CRP, IL-1β and AKR1C4, using RT-qPCR. Data were analyzed by mixed procedure of SAS. ALG mares had smaller uterine horns diameters and greater uterine echogenicity during post-partum in comparison with CONT. No treatment effects were detected for other characteristics evaluated, but a day effect was observed for uterine and endometrium diameter, IUF, uterine echogenicity, and transcript abundance of endometrial AKR1C4. Supplementation with DHA during peripartum may benefit uterine involution process and odds of early conception, but more studies should be performed regarding fertility.

Endometritis decreases the population of uterine neurons in the paracervical ganglion and changes the expression of sympathetic neurotransmitters in sexually mature gilts

BACKGROUND

The focus of the study was to examine the impact of the inflamed uterus on the population of the paracervical ganglion (PCG) uterus-innervating perikarya and their chemical coding. Fast Blue retrograde tracer was injected into the wall of uterine horns on the 17th day of the first studied estrous cycle. After 28 days, either Escherichia coli suspension or saline was applied to the horns of the uterus, whereas the control group received laparotomy only. Eight days after the above-mentioned procedures, uterine cervices with PCG were collected. Both macroscopic and histopathologic examinations confirmed severe acute endometritis in the Escherichia coli-injected uteri. The double immunofluorescence method was used to analyze changes in the PCG populations coded with dopamine-β-hydroxylase (DβH) and/or neuropeptide Y (NPY), somatostatin (SOM), vasoactive intestinal polypeptide (VIP) and neuronal isoform of nitric oxide synthase (nNOS).

RESULTS

The use of Escherichia coli lowered the total number of Fast Blue-positive neurons. Moreover, an increase in DβH+/VIP+, DβH+/NPY+, DβH+/SOM + and DβH+/nNOS + expressing perikarya was noted. A rise in non-noradrenergic VIP-, SOM- and nNOS-immunopositive populations was also recorded, as well as a drop in DβH-positive neurotransmitter-negative neurons.

CONCLUSIONS

To sum up, inflammation of the uterus has an impact on the neurochemical properties of the uterine perikarya in PCG, possibly affecting the functions of the organ.

Interaction of preimplantation factor with the global bovine endometrial transcriptome

Preimplantation factor (PIF) is an embryo derived peptide which exerts an immune modulatory effect on human endometrium, promoting immune tolerance to the embryo whilst maintaining the immune response to invading pathogens. While bovine embryos secrete PIF, the effect on the bovine endometrium is unknown. Maternal recognition of pregnancy is driven by an embryo-maternal cross talk, however the process differs between humans and cattle. As many embryos are lost during the early part of pregnancy in cattle, a greater knowledge of factors affecting the embryo-maternal crosstalk, such as PIF, is needed to improve fertility. Therefore, for the first time, we demonstrate the effect of synthetic PIF (sPIF) on the bovine transcriptome in an ex vivo bovine endometrial tissue culture model. Explants were cultured for 30h with sPIF (100nM) or in control media. Total RNA was analysed via RNA-sequencing. As a result of sPIF treatment, 102 genes were differentially expressed compared to the control (Padj<0.1), although none by more than 2-fold. The majority of genes (78) were downregulated. Pathway analysis revealed targeting of several immune based pathways. Genes for the TNF, NF-κB, IL-17, MAPK and TLR signalling pathways were down-regulated by sPIF. However, some immune genes were demonstrated to be upregulated following sPIF treatment, including C3. Steroid biosynthesis was the only over-represented pathway with all genes upregulated. We demonstrate that sPIF can modulate the bovine endometrial transcriptome in an immune modulatory manner, like that in the human endometrium, however, the regulation of genes was much weaker than in previous human work.

Evaluation of oxidant/antioxidant status, metabolic profile and milk production in cows with metritis

Background

The aim of the study was to evaluate oxidant/antioxidant status in 21 Holstein dairy cows with metritis compared to 8 healthy controls. Blood samples were taken during the first 21 days postpartum. Malondialdehyde (MDA), a marker of oxidative stress, total antioxidant status (TAS) and antioxidant parameters such as glutathione peroxidase (GPx), selenium (Se), vitamins A and E and beta-carotene were determined from all cows. The differences in beta-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), calcium, bilirubin concentrations and aspartate aminotransferase (AST) activity were also monitored, as were milk production and milk composition. Metritis was defined by an unpleasant discharge of varying color (milky-grey/brown/sanguineous) and consistency (muco-purulent/purulent/watery) and by the presence of increased temperature (> 38.5 °C) in cows within 21 days postpartum. Rectal examination revealed increased uterine size, thickened uterine wall and increased uterine tone. The affected cows had significantly reduced daily milk production. Additionally, hematological parameters and haptoglobin concentration were also measured in metritic cows.

Results

Higher MDA concentration (P <  0.001) was recorded in cows with metritis, while vitamin A and vitamin E concentrations were lower (P <  0.01) compared to healthy cows. Higher BHB (P <  0.05), NEFA (P <  0.05), AST (P <  0.05) and bilirubin (P <  0.001) concentrations was recorded in cows with metritis as compared to the control group. Significant differences in beta-carotene concentration, GPx activity, and Se, TAS and Ca concentrations in cows with metritis compared to control group were not observed in the present study (P >  0.05). Milk production was decreased in the cows with metritis (P <  0.001) and alterations in milk composition were also observed in metritic cows as compared to healthy cows.

Conclusions

The results of the study showed that cows with metritis in early postpartum are exposed to a higher degree of oxidative stress and that the incidence of metritis can negatively affect milk production in dairy cows.

Progesterone inhibits inflammatory response in E.coli- or LPS-Stimulated bovine endometrial epithelial cells by NF-κB and MAPK pathways

Progesterone suppresses the innate immune function of bovine endometrium, making the uterus susceptible to bacterial infection. The bovine endometrial epithelial cells (BEEC) are the first line of defense against bacteria, such as Escherichia coli (E.coli) that causes inflammation of endometrium through the recognition of lipopolysaccharide (LPS). The aim of this study was to investigate the effect of progesterone on the inflammatory response and its potential mechanism using E.coli- or LPS-induced BEEC. Concentrations of 1, 3 and 5 ng/mL progesterone were selected. The mRNA expressions of proinflammatory cytokines were determined using qPCR. The activations of NF-κB and MAPK pathways were detected by Western blot and immunofluorescence. An increase in the mRNA expression of IL-1β, IL-6, IL-8 and TNF-α was observed in BEEC treated with progesterone, LPS or E.coli alone. Progesterone inhibited the E.coli- or LPS-induced gene expression of these cytokines. Progesterone treatment alone showed little influence on NF-κB or MAPK pathway. In BEEC stimulated with E.coli or LPS, progesterone inhibited the phosphorylations of IκB, p65, ERK1/2, p38MAPK and JNK, and the translocation of p65 into the nucleus. These results suggested that progesterone has anti-inflammatory effect, which may be mediated by inhibiting NF-κB activation and MAPK phosphorylation in BEEC.

Preventing postpartum uterine disease in dairy cattle depends on avoiding, tolerating and resisting pathogenic bacteria

Up to forty percent of dairy cows develop metritis or endometritis when pathogenic bacteria infect the uterus after parturition. However, resilient cows remain healthy even when exposed to the same pathogens. Here, we provide a perspective on the mechanisms that dairy cows use to prevent postpartum uterine disease. We suggest that resilient cows prevent the development of uterine disease using the three complementary defensive strategies of avoiding, tolerating and resisting infection with pathogenic bacteria. Avoidance maintains health by limiting the exposure to pathogens. Avoidance mechanisms include intrinsic behaviors to reduce the risk of infection by avoiding pathogens or infected animals, perhaps signaled by the fetid odor of uterine disease. Tolerance improves health by limiting the tissue damage caused by the pathogens. Tolerance mechanisms include neutralizing bacterial toxins, protecting cells against damage, enhancing tissue repair, and reprogramming metabolism. Resistance improves health by limiting the pathogen burden. Resistance mechanisms include inflammation driven by innate immunity and adaptive immunity, with the aim of killing and eliminating pathogenic bacteria. Farmers can also help cows prevent the development of postpartum uterine disease by avoiding trauma to the genital tract, reducing stress, and feeding animals appropriately during the transition period. Understanding the mechanisms of avoidance, tolerance and resistance to pathogens will inform strategies to generate resilient animals and prevent uterine disease.

Problem of chronic endometritis in cows and ways to solve it

Chronic endometritis is diagnosed on average in 18.1 % of infertile cows. With chronic endometritis, the uterus has a pronounced cavity of 18.4±0.9 mm (11–35 mm), while the wall thickness of the uterus is on average 8.7±0.37 mm. Morphometrically chronic endometritis is characterized by a decrease in the fraction of functionally active elements of the endometrium (integument epithelium, uterine glands, blood vessels) to 12.17 %. In the development of chronic endometritis, cows compared with clinically healthy animals showed an increase in leukocyte content by 12.2 %, monocytes by 2.5 times, creatinine by 29.7 %, average molecular peptides by 25.0 %, and endogenous intoxication index by 25.4 %, circulating immune complexes by 38.5 %, with a decrease in the bactericidal and lysozyme activity of blood serum, respectively by 10.7 and 12.9 % and phagocytic activity of leukocytes by 12.4 %. The effectiveness of the application of the developed method for the treatment of chronic endometritis, involving the use of aminoseleton five times with a 72-hour interval at a dose of 30, 35, 40, 45 and 50 ml, magestrofan on the 1st and 13th days at a dose of 2 ml, uterotone on 3rd, 4th and 5th days at a dose of 10 ml and intrauterine administration of primalact on 1st-3rd days at a dose of 20 ml, is 88.0 %. Recovery of animals after the treatment is accompanied by a decrease in the inflammatory response, endogenous intoxication, normalization of liver and kidneys, an increase in overall non-specific resistance and a decrease in uterine microbial contamination.

Immune status during postpartum, peri-implantation and early pregnancy in cattle: An updated view

Throughout the estrous cycle the mammalian endometrium undergoes morphological and functional changes that are essential for the establishment of pregnancy and proper ovarian and uterine functions. Among these changes, the most important are alterations in both inter- and intracellular signalling molecules, many of which modulate immune processes. In the endometrial tissue there are local innate (nonspecific) and adaptive (specific/acquired) response mechanisms which vary because of the endocrine status during the estrous cycle, pregnancy and postpartum period. Endometrial cells have responses that support the immune system by producing pro-inflammatory factors such as cytokines, sensors, effector molecules and chemokines. This response is important during gestation, pregnancy, and fetal growth, as well as in preventing infection, and immuno-rejection of the semi-allogeneic embryo. In dairy cows, both before and immediately after calving, there are marked changes in the values for hormonal and metabolic variables and the immune status is impaired. Thus, in several studies there has been assessment of the physiological and/or abnormal maternal immune changes and possible effects on dairy cow reproductive performance. The objective with this review is to summarize the novel information about the immune mechanisms involved during the postpartum period, subsequent peri-implantation period and pregnancy in dairy cows, and the possible effects on reproductive performance. This information provides for an enhanced understanding of the local and systemic immune responses associated with the metabolic and hormonal status of dairy cows, and alterations in the immune system of high producing cows and the possible effects on subsequent fertility.

Changes in Blood Lymphocyte Subpopulations and Expression of MHC-II Molecules in Wild Mares Before and After Parturition

Introduction

Pregnancy is a physiological state in which the immune system undergoes certain changes. On the one hand, by depleting cell defence mechanisms, it favours development and maintenance of the pregnancy. At the same time cells of the immune system ensure resistance to many risk factors, including infectious agents.

Material and Methods

The study was carried out on 24 Polish Konik breed mares which were divided into two equal groups. The first group (group I) included mares living in the reserve. The second group (group II) comprised mares maintained under conventional conditions in the stables. The blood samples were collected for the first time in the perinatal period, i.e. 2 weeks before parturition (trial 0), then within the first 24 h after delivery, and then on 7^th and 21^st day after foaling. Flow cytometric analysis of lymphocyte expressing TCD4+, TCD8+, CD2+, and MHC class II antigens was performed.

Results

Before the delivery, in group I there was a significantly higher CD4:CD8 ratio compared to group II (P ≤ 0.05). Similarly, significantly increased CD4:CD8 ratio in group I was noted within 24 h after parturition (P ≤ 0.001) and it was also observed on 7^th day (P ≤ 0.03) and 21^st day after foaling (P ≤ 0.02). In the first 24 h after parturition, a significant decline of lymphocytes CD8+ (P ≤ 0.02) was noted. No significant differences in terms of lymphocytes CD2+ and CD3+ were observed. Expression of MHC-II molecules before and after the parturition was higher in group I compared to group II; however, the difference between the groups was not significant.

Conclusion

The results obtained indicate that mares living in the reserve display higher activity of cell defence mechanisms.

Bovine herpes virus type-4 infection among postpartum dairy cows in California: risk factors and phylogenetic analysis

The aims of this study were to determine the prevalence and associated risk factors of bovine herpes virus type-4 (BoHV-4) infection and describe the genetic characteristics and predominant genotypes of the virus in Yolo and Tulare counties, California. A cross-sectional study involving multi-stage sampling technique was used. One hundred and forty-eight post-partum cows were enrolled from 11 dairy farms. Uterine/vaginal samples were collected and tested for BoHV-4 and other co-infecting viruses using real-time PCR. Data were analysed using multilevel logistic mixed-effect model. Phylogenetic analysis of 10 BoHV-4 isolates was conducted by targeting three open reading frames (ORF3, ORF8 and ORF 22) of the viral genome. The prevalence of BoHV-4 infection was 22.3% (33/148), while post-partum metritis was 33.8% (48/142). Strong association was found between BoHV-4 infection and lactation number, lactation stage and post-partum metritis. The odds of being positive for BoHV-4 infection were 6.47 times (95% CI 1.17-35.92; P 240 days). Cows with post-partum metritis were 4.51 times (95% CI 1.27-16.02; P < 0.05) more likely to test positive for BoHV-4 infection compared with those without post-partum metritis. Phylogenetic analysis of BoHV-4 based on sequencing of glycoprotein and thymidine kinase (TK) genes revealed genetic variability of the virus with glycoprotein B genotype 1 and TK genotype 2 as being dominant genotypes. The reported high genetic variability of BoHV-4 indicates the possibility of co-infection with multiple genotypes.

Effects of preimplantation factor on interleukin-6 and prostaglandin F2α and E2 in the bovine endometrium

Preimplantation factor (PIF) is a pregnancy specific peptide with immune modulatory properties exerted on the human endometrium. Viable bovine embryos secrete PIF, but its effect on the bovine endometrial immune response is unknown, both in native and inflammatory stimulated endometrial tissue. An ex vivo bovine endometrial tissue culture model was used with lipopolysaccharide (LPS) as an inflammatory stimulant. The effect of synthetic PIF (sPIF) was assessed, in three separate experiments, on the secretion or mRNA expression of essential prostaglandins and cytokines. Radioimmunoassays were used to assess prostaglandin secretion and ELISA for IL-6 secretion from endometrial explants. mRNA expression of IL6 and IL8 was analysed from endometrial explants with real-time PCR. Synthetic PIF reduced native IL-6 secretion from explants when pre-treated for 24 h. There was no effect of sPIF on IL-6 secretion from LPS challenged explants; however, sPIF increased IL6 mRNA expression when challenged with 500 ng/mL LPS. There was no effect of sPIF on prostaglandin secretion or mRNA expression of IL8. Therefore, sPIF is able to modulate the native IL-6 production pathway in the bovine endometrium, yet demonstrates no effect on prostaglandin secretion or IL8 expression. Unlike in human studies, effects of sPIF were minimal, thus sPIF is not an effective modulator of the immune targets investigated in the bovine endometrium.

Cytological endometritis at artificial insemination in dairy cows: Prevalence and effect on pregnancy outcome

The aims of our field study in dairy cows were (1) to consolidate cytotape (CT) as a valid technique to diagnose cytological endometritis (CYTO) during artificial insemination (AI); (2) to establish a cutoff point concerning the polymorphonuclear cells (PMN) proportion to diagnose CYTO at AI; (3) to assess the prevalence of CYTO at AI; and (4) to evaluate the effect of CYTO on the pregnancy outcome of that AI. The investigation was performed using 1,625 AI-CT samples harvested from 873 Holstein-Friesian cows from 18 dairy farms in the Flemish region of Belgium. The CT device consisted of adapting a 1.5-cm piece of paper tape on the top of a conventional AI catheter covered with a double guard sheet, allowing an endometrial cytology sample to be taken when performing an AI. A receiving operator characteristic curve was built to assess the threshold level above which the PMN proportion significantly affected the AI success. Multilevel generalized mixed-effect models were built to identify factors affecting the pregnancy outcome of the AI under investigation. Only 7 samples (0.4%) harvested in 5 cows were discarded because of low-quality parameters. The cutoff point for CYTO at AI was set at ≥1% PMN (sensitivity=33.8%, specificity=88.6%). Prevalence of CYTO at AI was 27.8%. The conception rate for CYTO-positive samples was 32.7%, whereas it was 47% for CYTO-negative samples. A CYTO-negative AI had 1.8 [odds ratio (OR)] more chances to become pregnant than a CYTO-positive one. Other factors identified as detrimental for the pregnancy outcome were body condition score ≤1.5 (OR=0.6), relative 305-d milk yield (OR=0.9), dystocia (OR=0.3), parity ≥2 (OR=0.7), and warm months of the year. In conclusion, CT is a consolidated technique to diagnose CYTO at AI, PMN 1% is the threshold level to diagnose CYTO at AI, around one-quarter of inseminated uteri suffer from CYTO, and affected uteri having a significantly lower chance to become pregnant from that insemination.

Factors associated with ovarian structures and intrauterine fluid in the postpartum period in dairy cows

The objective was to examine risk factors for the interval to resumption of ovarian cyclicity (ROC), multiple ovulations (MCL), ovarian follicular cysts (OC), and presence of intrauterine fluid (IUF) at 22 to 28 [visit (V) 1] and 36 to 42 (V2) days in milk (DIM) in dairy cows. The study was conducted retrospectively by evaluating records from 1,155 Holstein cows from 3 herds. Ovaries and uteri were examined at V1 and V2 by transrectal ultrasonography to determine ovarian structures and IUF. Based on the odds ratio, multiparous cows were more likely to have ROC at V1 by a factor of 1.79 compared with primiparous cows. The likelihood of ROC at V1 was lower in cows with higher milk production, in cows with retained fetal membranes (RFM) or cows with IUF at V1 by factors of 0.98 (for each kg of milk increased), 0.52, and 0.61, respectively. Based on the odds ratio, cows diagnosed with IUF at V2 were 2.85 times more likely to have attained ROC at V2. Multiparous cows and cows that delivered twins were 2.73 and 2.16 times, respectively, more likely to have MCL at V1, whereas cows with RFM were 0.38 times less likely to have MCL at V1. The likelihood of MCL at V2 was higher in cows with MCL and OC at V1 by factors of 2.67 and 1.91, respectively. Multiparous cows were 8.51 times more likely to have OC at V1 than primiparous cows. Higher producing cows were more likely to have OC at V2 by a factor of 1.04 compared with lower producing cows. Parity, stillbirth, RFM, and ROC at V1 were all identified as risk factors for IUF at V1. Cows with RFM and delivering twins were more likely to be diagnosed with IUF at V2 by a factor of 3.43 and 4.07, respectively. In summary, parity, twinning, RFM, metritis, IUF, and milk production were all associated with altered ovarian structures, and the presence of IUF was related to parity, twinning, RFM, and ROC in postpartum dairy cows.

Synthesis of leukotrienes in porcine uteri with endometritis induced by infection with Escherichia coli

Leukotrienes (LTs) are lipid mediators that play a significant role in the inflammatory process. Their production in inflamed uteri is not fully understood. The present experiment aimed to determine LTB4 and LTC4 amounts, 5-lipooxygenase (5-LO), LTA4 hydrolase (LTAH) and LTC4 synthase (LTCS) mRNA levels and protein expression in inflamed porcine uteri. On Day 3 of the oestrous cycle (Day 0 of the study), either Escherichia coli suspension or saline were infused into uterine horns. Collection of uterine tissues and washings took place eight or sixteen days later. In gilts suffering from endometritis increased LTB4 and LTC4 levels in the endometrium and washings and 5-LO mRNA levels in the myometrium on Days 8 and 16, 5-LO protein levels in the endometrium and myometrium on Day 8, LTAH mRNA and protein levels in the endometrium and myometrium on Days 8 and 16, respectively. Although LTCS mRNA and protein expression in the myometrium and LTCS protein expression in the endometrium were enhanced on Day 16 after Escherichia coli inoculation, LTCS mRNA levels decreased on Day 8 in both tissues. Our study shows the upregulation of LT production in inflamed porcine uteri, which suggests the importance of these factors to the process of uterine inflammation.

Transcriptomic analysis of the myometrium during peri-implantation period and luteolysis--the study on the pig model

In pigs, implantation begins with the attachment of embryos to the endometrium. As the process is regulated by the expression of numerous genes, endometrial transcriptomic profiles have been extensively studied in early gravid pigs. However, the myometrium, a secretory tissue, should not be neglected, as it can also participate in the regulation of implantation in early pregnant pigs. To clarify this issue, the transcriptomic profile of the porcine myometrium during the peri-implantation period (i.e. on days 15 to 16 of pregnancy) was compared with the profile observed during luteolysis (i.e. on days 15 to 16 of the oestrous cycle) with an Agilent’s Porcine (V2) Two-Colour Gene Expression Microarray 4 × 44 (Agilent, USA). Analysis of the microarray data revealed that of 526 unique, accurately annotated genes, the expression of 271 unique genes was upregulated, while the expression of 255 genes was downregulated in pregnant versus cyclic myometrium. The in-depth data analysis revealed differential expression of genes encoding for factors involved in immunomodulation, tissue growth and differentiation, and prostaglandin and steroid biosynthesis and action. Moreover, the comparison of the obtained data on the myometrial transcriptome with our previously published results on the endometrial transcriptome allowed us to determine substantial differences in the regulatory function of both tissues. The new insights into the function of the myometrium of early pregnant pigs obtained here are in agreement with our previous results that suggest that this tissue plays an important role in providing optimal conditions for developing embryos. Therefore, the importance of the myometrium as an active embryo signal-responsive tissue during early pregnancy cannot be underestimated.

Does Coxiella burnetii affect reproduction in cattle? A clinical update

Q fever is a zoonosis produced by Coxiella burnetii, a bacterium that is widely distributed worldwide. Domestic ruminants are the most important source of C. burnetii for human infection. In sheep and goats, abortion is the main clinical consequence of infection, yet the symptoms described in cattle have so far been inconsistent. Q fever has been also scarcely reported in cattle, most likely because of its difficult diagnosis at the farm level and because of the many existing responsible C. burnetii strains. In this report, the effects of C. burnetii infection or Q fever disease on the reproductive behaviour of dairy cattle are reviewed, with special emphasis placed on the scarcity of data available and possible control actions discussed.

Influence of the uterine inflammatory response after insemination with frozen-thawed semen on serum concentrations of acute phase proteins in mares

The aim of this study was to investigate the clinical relevance of measuring blood concentrations of serum amyloid A (SAA), haptoglobin (Hp) and fibrinogen (Fib) in horse reproductive management, and changes in response to artificial insemination (AI) with frozen-thawed semen. Standardbred mares (n=18) with different reproductive status (eight healthy mares in first postpartum oestrus, five healthy barren mares and five mares with endometritis) were inseminated with frozen-thawed semen. Endometritis was evaluated during oestrus by bacteriological culture, cytology and presence of ultrasonically visible intrauterine fluid during oestrus. Concentrations of SAA, Hp and Fib were analysed in the blood in every 48h during oestrus and until 5, 6 or 7 days after AI. The day of sampling and number of blood samples varied between mares because of length of the oestrus and time of AI. Changes in concentrations of SAA, Hp and Fib were evaluated based on the day of sampling regard to AI and classification of the mares. There were no differences in SAA, Hp and Fib concentrations over time before or after AI or between the groups of mares. The insemination of mares with frozen-thawed semen did not increase the plasma concentrations of SAA, Hp and Fib above clinical threshold concentration and there were no differences between susceptible or healthy mares.

Strategies for the treatment of dairy cows at high risk for postpartum metritis and for the treatment of clinical endometritis in Argentina

The objectives of this study were to evaluate the efficacy of (1) administering ceftiofur hydrochloride in dairy cows with calving-related disorders to prevent metritis and (2) a combination of GnRH and PGF2α for the treatment of clinical endometritis, under Argentinean dairy farming conditions. Cows at high risk (HRC) for metritis (dystocia, RFM >12 h postpartum, hypocalcaemia, twins, or stillbirth) were randomly assigned to receive either 1.1 mg/Kg of ceftiofur hydrochloride on three consecutive days (HRC treated group HRCT, n = 110) or remained untreated (HRC control group HRCC, n = 126). Cows with low risk (LRC, no calving-related disorders, n = 868) did not receive any treatment (LRC group, n = 868). All cows were examined for metritis between days 4 and 10 and for clinical endometritis between 24 and 30 days postpartum. The body condition score (BCS) was recorded at both examinations. Cows with endometritis at days 24 to 30 postpartum received either 1.5 mg of D-cloprostenol (PGF; n = 129) or 100 μg of GnRH followed by D-cloprostenol after 7 days (GnRH+PGF, n = 119). There was no overall effect of treatment on the incidence of metritis or on time to pregnancy. Treatment, however, reduced the incidence of metritis in cows with high BCS (HRCT = 24.0 %, HRCC = 38.5 %) but had no effect in cows with low BCS (HRCT = 38.7 %, HRCC = 37.5 %). The proportion of pregnant cows by days in milk was greater (P < 0.01) in LRC group compared with that of the HRCT and HRCC groups. No significant differences were found between groups PG and PG+GNRH. GnRH+PGF treatment, however, tended (P = 0.06) to increase pregnancy rate in cows with a moderate loss of BCS (76.5 vs 65.2 %) but tended to reduce pregnancy rate (54.5 vs 76.0 %) in cows with a more pronounced loss in BCS (>0.75 points).

Effects of 1 or 2 treatments with prostaglandin F₂α on subclinical endometritis and fertility in lactating dairy cows inseminated by timed artificial insemination

The objectives of the current study were to investigate the efficacy of PGF₂α as a therapy to reduce the prevalence of subclinical endometritis and improve pregnancy per artificial insemination (P/AI) in cows subjected to a timed artificial insemination (AI) program. A total of 1,342 lactating Holstein dairy cows were allocated randomly at 25 ± 3 d in milk (DIM) to remain as untreated controls (control, n=454) or to receive a single PGF₂α treatment at 39 ± 3 DIM (1PGF, n=474) or 2 treatments with PGF(α at 25 ± 3 and 39 ± 3 DIM (2PGF, n=414). All cows were enrolled in the double Ovsynch program at 48 ± 3 DIM and were inseminated at 75 ± 3 DIM. A subset of 357 cows had uterine samples collected for cytological examination at 25 ± 3, 32 ± 3, and 46 ± 3 DIM to determine the percentage of polymorphonuclear leukocytes (PMNL). Subclinical endometritis was defined by the presence of ≥ 5% PMNL. Vaginal discharge score was evaluated at 25 ± 3 DIM and used to define the prevalence of purulent vaginal discharge. Body condition score was assessed at 25 ± 3 DIM. Pregnancy was diagnosed 32 d after AI and reconfirmed 28 d later. At 32 ± 3 DIM, the prevalence of subclinical endometritis was reduced by treatment with PGF₂α at 25 ± 3 DIM in 2PGF (control=23.5% vs. 1PGF=28.3% vs. 2PGF=16.7%); however, this benefit disappeared at 46 ± 3 DIM, and 14% of the cows remained with subclinical endometritis. One or 2 treatments with PGF₂α did not influence P/AI on d 32 or 60 after timed AI, which averaged 39.9 and 35.2%. Similarly, treatment with PGF₂α had no effect on pregnancy loss between 32 and 60 d of gestation (11.9%). Cows diagnosed with both purulent vaginal discharge and subclinical endometritis had the lowest P/AI and the highest pregnancy loss compared with those diagnosed with only 1 of the 2 diseases or compared with cows having no diagnosis of uterine diseases. Interestingly, subclinical endometritis depressed P/AI and increased pregnancy loss only when it persisted until 46 DIM. On d 32 after AI, cows not diagnosed with subclinical endometritis and those that resolved subclinical endometritis by 46 DIM had greater P/AI than those that remained with subclinical endometritis at 46 DIM (45.4 and 40.0 vs. 25.0%, respectively). Similar to P/AI, cows not diagnosed with subclinical endometritis and those that resolved subclinical endometritis by 46 DIM had less pregnancy loss than those with subclinical endometritis at 46 DIM (9.6 and 13.5 vs. 43.9%, respectively). One or 2 treatments with PGF₂α before initiation of the timed AI program were unable to improve uterine health, P/AI, and maintenance of pregnancy in lactating dairy cows. Cows diagnosed with both purulent vaginal discharge and subclinical endometritis had the greatest depressions in measures of fertility at first AI, particularly when subclinical endometritis persisted in the early postpartum period.

Reproductive performance of high producing lactating cows in Coxiella-infected herds following vaccination with phase-I Coxiella burnetii vaccine during advanced pregnancy

This study was designed to assess the safety of phase I vaccination against Coxiella burnetii in advanced pregnancy and the effect of vaccination on subsequent reproductive performance of high producing dairy cows. C. burnetii serostatus was determined in 719 dairy cows by individual serological testing. According to their serostatus, cows were randomly assigned to a control (n=359) or vaccine (n=360) group (inactivated phase I on Days 171-177 and 192-198 of gestation, Coxevac-Ceva Sante Animale). Using a χ(2)-test, vaccination had no effect on abortion before parturition, retention of placenta and stillbirth, either in seropositive as in seronegative cows. Cox's proportional hazards model revealed that cows in the vaccine group were 1.22 times more likely to conceive during the first 150 days in milk than cows in the control group. Moreover, the likelihood of pregnancy was lower in multiparous cows, cows with a retained placenta and cows undergoing first AI during the warm season compared to the remaining animals (by factors of 0.75, 0.69 and 0.69, respectively). In animals testing seronegative for C. burnetii, the likelihood of pregnancy was 1.25 times higher in vaccinated cows compared to non-vaccinated seronegative animals. No effect of vaccination on subsequent fertility was detected in seropositive animals. In conclusion, the results of this study indicate that phase I vaccination against C. burnetii during advanced pregnancy in dairy cows is safe and improves subsequent fertility of C. burnetii seronegative animals.

Coxiella burnetii shedding during the peripartum period and subsequent fertility in dairy cattle

The objective of this study was to assess the effects of Coxiella burnetii shedding or seropositivity on post-partum recovery and subsequent fertility in high-producing dairy cows. Given the difficulty in diagnosing C. burnetii infection at the farm level, an exhaustive series of tests in 43 pregnant animals that delivered at least one live calf were conducted, including blood serology and PCR of milk or colostrum, cotyledons (only at parturition), faeces, vaginal fluid against C. burnetii on gestation Day 171-177, at parturition and on Days 1-7, 8-14, 15-21, 22-28, 29-35 and 90-97 post-partum. During scheduled herd visits, ultrasonography (US) of the genital tract and examination of vaginal fluid were performed on Days 15-21 (V1), 22-28 (V2), 29-35 (V3) and 51-57 (V4) post-partum by the same veterinarian. Logistic regression analysis revealed that the likelihood of suffering endometritis (the presence of echogenic intrauterine fluid (IUF), cervical diameter of ≥4 cm or endometrial thickness ≥0.75 cm) was lower in C. burnetii-seropositive animals (OR = 0.10), compared with C. burnetii-seronegative animals. According to Kaplan-Meier survival analysis, C. burnetii-seronegative and non-shedding cows showed a delayed return to luteal activity and conception was delayed in non-shedding animals, compared with the remaining animals. Overall, the results of our study provide useful insight into the effects of C. burnetii infection on post-partum recovery and subsequent fertility. In particular, animals not infected with Coxiella seem to be susceptible to infection and not protected against the bacterium in dairy herds. The elevated costs of determining an infection at the farm level, make monitoring of cows virtually impossible from a clinical point of view.

Influences of metabolic traits on subclinical endometritis at different intervals postpartum in high milking cows

Seventy pluriparous high-yielding cows were used to investigate the impact of metabolic traits and body condition score (BCS) during early lactation on subclinical endometritis diagnosed at weeks 5, 6 and 7 postpartum (pp). Blood samples were collected from animals with no peripartum problems from the second (W2) to seventh (W7) weeks pp to estimate some blood metabolites including non-esterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), blood glucose, total cholesterol (T-chol) and blood urea nitrogen (BUN). Reproductive tract examination was carried out at weeks 5, 6 and 7 pp by endometrial cytology (percentage of polymorphonuclear cells; PMN%). Based on PMN%, animals having <5% were defined as subclinical endometritis group (ENDM group) while animals unaffected by endometritis were defined as no subclinical endometritis group (NOENDM group). Animals with endometritis during week 5 were identified as ENDM5, during week 6 identified as ENDM6 and during week 7 identified as ENDM7 or animals with no endometritis during weeks 5 (NOENDM5), 6 (NOENDM6) and 7 (NOENDM7) pp. Animals diagnosed at week 5; BUN and BCS were lower p < 0.05 in ENDM 5 than NOENDM5 group at W2, W4, W6 and W7. Cows diagnosed at week 6; T-chol was significantly higher (p = 0.05) in ENDM6 group (279.2 ± 12.5 mg/dl) than NOENDM6 group (246 ± 9.5 mg/dl) at W7. Moreover, blood glucose was significantly low (p < 0.05) in ENDM6 group when compared to NOENDM group at W4 pp (49.2 ± 1.8 vs 53.8 ± 1.3 mg/dl). BCS was significantly lower (p < 0.001) in animals suffered from endometritis during week 7 when compared to NOENDM7 cows at W3, W4, W5, W6 and W7. In conclusion, lower blood glucose, BUN and BCS could be a risk factor for cytologically diagnosed endometritis at weeks 5, 6 and 7 pp.

Impact of ovarian and uterine conditions on some diagnostic tests output of endometritis in postpartum high-yielding dairy cows

The effect of ovarian predominating structures and uterine condition on the result of some diagnostic tools for the evaluation of endometritis was studied in postpartum (pp) Holstein-Friesian dairy cows (n = 58). Endometrial cytology (EC) and the evaluation of vaginal mucus by vaginoscopy or Metricheck were performed weekly from week 3 to 7 pp. The ovarian studies involved the predominating structures including cystic follicles with plasma progesterone (P(4) ; more or <1 ng/ml; >23 mm), corpus luteum (CL), pre-ovulatory follicles (10-23 mm) and small follicles (<10 mm). The uterine conditions comprised uterine involution, tonicity and fluid in uterus (FIU) regarding echogenicity extent. During week 5, the percentage of polymorphonuclear neutrophils (PMN%) was higher (p < 0.05) in animals with pre-ovulatory follicles (mean ± SEM, 26.3 ± 7.6%) than animals having CL (11.0 ± 3.6%). In cystic ovaries, during week 5, PMN% was higher (p < 0.05) in follicular cysts with low progesterone (P(4) < 1 ng/ml; 9.3 ± 2.6%) than those with high P(4) (P(4) ≥ 1 ng/ml; 1.5 ± 1.1%). Moreover, PMN% was higher (p < 0.01) in animals with non-involuted uterus (11.5 ± 7.4%) than those with involuted uterus (2.7 ± 0.6%) during week 7 pp. The animals that had abnormal mucus determined by Metricheck was higher in animals with atonic uterus than those with tonic uterus during week 6 (82.6% vs 51.5%; p < 0.05) and 7 (71.4% vs 25.7%; p < 0.01) pp. In addition, by vaginoscopy, the prevalence of animals with abnormal discharge showing small follicles (100%, 5/5) during week 3 pp and pre-ovulatory follicles (40.0%, 8/20) during week 5 pp was higher (p < 0.05) when compared to those having CL during week 3 (33.3%; 1/3) and week 5 pp (7.7%; 2/26), respectively. In conclusion, endometrial cytology, Metricheck and vaginoscopy were influenced by the predominating various ovarian structures and uterine condition in early pp high-yielding dairy cows.

Regulation of dendritic cells by female sex steroids: Relevance to immunity and autoimmunity

Dendritic cells (DCs) are critical mediators of adaptive immunity, tolerance and autoimmunity. The human immune system exhibits sexual dimorphism, which is most evident in the female predominance of autoimmune diseases such as systemic lupus erythematosus (SLE). Female sex steroids are strongly implicated in mediating immune sexual dimorphism, in part because estrogen accentuates disease in several models of lupus autoimmunity. In contrast, progesterone may prevent disease development. While much investigation has focused on the effects of estrogen and progesterone on lymphocyte functions, far less attention has been paid to the effects of these hormones on DCs. Current evidence now indicates estrogen can activate DCs, while in contrast, progesterone inhibits DC functions. Thus, we hypothesize that the opposite effects these two hormones have on lupus autoimmunity reflect opposing effects on DC functions. Thus, through direct actions on DCs, female sex steroids may influence autoimmunity, immunity and tolerance.

Beneficial effects on the reproductive performance of sows of administering prostaglandin analogues after farrowing

Twenty-four to 36 hours after farrowing, 192 sows were treated with a single intramuscular injection (2 ml per animal) of a prostaglandin analogue; 102 were treated with cloprostenol racemate and 97 with dinoprost tromethamine, and 90 were left untreated. There were no statistically significant differences between the groups in the percentages of sows that came into oestrus by eight days after weaning or conceived by eight days after weaning. Significantly more piglets were born per litter (10.71 and 11.00 piglets in the cloprostenol and dinoprost groups, respectively) and born alive (10.22 and 10.41, respectively) than in the controls (9.24 piglets born per litter and 8.66 piglets born alive).

Immunopathogenesis of pelvic endometriosis: role of hepatocyte growth factor, macrophages and ovarian steroids

Endometriosis, a chronic disease characterized by endometrial tissue located outside the uterine cavity is associated with chronic pelvic pain and infertility. However, an in-depth understanding of the pathophysiology of endometriosis is still elusive. It is generally believed that besides ovarian steroid hormones, the growth of endometriosis can be regulated by innate immune system in pelvic microenvironment by their interaction with endometrial cells and immune cells. We conducted a series of studies in perspectives of pelvic inflammation that is triggered primarily by bacterial endotoxin (lipopolysaccharide) and is mediated by toll-like receptor 4 and showed their involvement in the development of pelvic endometriosis. As a cellular component of innate immune system, macrophages were found to play a central role in inducing pelvic inflammatory reaction. We further report here that peritoneal macrophages retain receptors encoding for estrogen and progesterone and ovarian steroids also participate in producing an inflammatory response in pelvic cavity and are involved in the growth of endometriosis either alone or in combination with hepatocyte growth factor (HGF). As a pleiotropic growth factor, HGF retains multifunctional role ometriosis. We describe here the individual and step-wise role of HGF, macrophages and ovarian steroid hormones and their orchestrated involvement in the immunopathogenesis of pelvic endometriosis.

Intra-vesicle administration of d-cloprostenol for induction of abortion in mid-gestation bitches

This study evaluated a new method for mid-gestation termination in the bitch, which consisted of ultrasound-guided administration of a single dose of d-cloprostenol, a PGF(2alpha) analogue, into a single gestational sac. Effects on serum progesterone concentration (P(4)) were also investigated. The study was performed between days 28 and 35 of gestation on 15 privately owned crossbred bitches, randomly divided into two groups: group A comprised 10 bitches treated with 15 microg per head d-cloprostenol diluted in 0.8 ml sterile saline (final volume 1 ml); group B comprised 5 bitches treated with 1 ml of sterile saline solution (0.9% NaCl), administered in the same way. In all bitches of group A, fetal death was successfully induced within 5 days (mean: 3.1 days, S.D. 1.2) with no clinical or behavioural complications. Mild adverse effects were observed in two bitches, each weighing less than 10 kg, including salivation, defecation and hyperventilation, which disappeared within 15 min. None of the subjects in group B aborted within 10 days post-treatment. In group A, P(4) declined 2.8 days before pregnancy termination to a mean value below 30 nmol/l (S.D. 2.9 nmol/l). However, two bitches showed a higher concentration of P(4) throughout the sampling period. Our study demonstrates that intra-vesicle administration of a single low dose of D-cloprostenol is an effective and safe technique for induction of abortion, which offers an additional option for termination of unwanted pregnancy in the mid-gestation bitch.

Endometrial explant culture for characterizing equine endometritis

PROBLEM

Endometritis after insemination is ubiquitous in the horse and is associated with semen and/or bacteria in the uterus. In up to 40% of horses, inflammation persists causing infertility. An endometrial explant culture was developed to study uterine secretion of prostaglandin F(2alpha) (PGF(2alpha)) in response to physiological and pathological challenge.

METHOD OF STUDY

Uteri were collected from mares, the endometrium dissected and explants from the uterine body or horn cultured in William's or RPMI medium. The response of explants to oxytocin, semen or bacteria compared to untreated tissue was tested by collecting medium after 24 and 72 hr and measuring PGF(2alpha) by radioimmunoassay.

RESULTS

Explants from the uterine horn and cultured in William's medium secreted the most PGF(2alpha) after challenge with oxytocin. Explants treated with semen produced a PGF(2alpha) response after 72 hr. Explants collected from mares in the transition season treated with killed S. zooepidemicus or E. coli lipopolysaccharide (LPS) secreted increased concentrations of PGF(2alpha) after 24 and 72 hr. The response to LPS was inhibited by polymyxin B. Follicular and luteal phase explants did not respond to treatments.

CONCLUSIONS

An endometrial explant culture was developed that measured PGF(2alpha) and may be used to study endometritis.

The effects of Arcanobacterium pyogenes on endometrial function in vitro, and on uterine and ovarian function in vivo

Uterine bacterial infection after parturition causes endometritis, perturbs ovarian function and leads to infertility in cattle. Although endometritis is caused by mixed infections, endometrial pathology is associated with the presence of Arcanobacterium pyogenes. The aims of the present study were to determine the effects of A. pyogenes on endometrial function in vitro, and on uterine and ovarian function in vivo. Heat-killed A. pyogenes did not affect the production of prostaglandin F2alpha (PGF) or prostaglandin E(2) (PGE) from endometrial explants, or purified populations of endometrial epithelial or stromal cells. However, the explants produced more PGF and PGE than controls when treated with a bacteria-free filtrate (BFF) cultured from A. pyogenes. Similarly, BFF stimulated PGF and PGE production by epithelial and stromal cells, respectively. So, BFF or control PBS was infused into the uterus of heifers (n=7 per group) for 8 days, starting the day after estrus. Emergence of the follicle wave, dominant follicle or corpus luteum diameter, and peripheral plasma FSH, LH, estradiol, progesterone, PGFM, or acute phase protein concentrations were unaffected by the BFF infusion. In the live animal it is likely that the intact uterine mucosa limits the exposure of the endometrial cells to the exotoxin of A. pyogenes, whereas the cells are readily exposed to the toxin in vitro.

Bacterial complications of postpartum uterine involution in cattle

The bacterial contamination of the postpartum uterus is a frequent finding which by itself does not disturb the anatomical and histological restoration of tubular genital tract. The improper balance between uterine infection and the intrauterine antimicrobial self-defence mechanisms, however, often results in complications, such as puerperal metritis, clinical endometritis, pyometra and subclinical endometritis. After reviewing the bacteriology of uterine involution, and the predisposing factors for its bacterial complications, this paper defines the different clinical forms, and summarizes their pathology, furthermore, the recent progress in diagnostic considerations and principles of current treatments for these diseases of bovine genitals.

Prostaglandin F2alpha Upregulates Uterine Immune Defenses in the Presence of the Immunosuppressive Steroid Progesterone

PROBLEM

Uterine infections often develop in some livestock species during the first luteal phase postpartum. Exogenous prostaglandin F(2alpha) (PGF(2alpha)) induces luteolysis, reduces progesterone, and enables the uterus to resolve infections. However, the effects of PGF(2alpha) on luteal function and on immune functions are confounded. These effects must be disentangled to determine whether alternatives to antibiotic treatments can be successfully developed.

METHOD OF STUDY

Treatments were in a 2 x 2 x 2 factorial arrangement. Main effects were ovariectomy or sham on day 0 (i.e. estrus), exogenous progesterone or sesame oil from day 0 to 11, and exogenous PGF(2alpha) or saline on day 9. Intrauterine inoculations with Arcanobacterium pyogenes and Escherichia coli were administered on day 6.

RESULTS

Ewes treated with exogenous PGF(2alpha) either did not have uterine infections, infections were less severe, or infections were resolving when uteri were examined on day 12, despite increased progesterone.

CONCLUSIONS

Exogenous PGF(2alpha) has effects on the resolution of uterine infections that are independent of its effects on luteal progesterone production.

Defining postpartum uterine disease in cattle

Uterine function is often compromised in cattle by bacterial contamination of the uterine lumen after parturition, and pathogenic bacteria often persist, causing uterine disease, a key cause of infertility in cattle. However, the definition or characterization of uterine disease frequently lacks precision or varies among research groups. The aim of the present paper was to provide clear clinical definitions of uterine disease that researchers could adopt. Puerperal metritis should be defined as an animal with an abnormally enlarged uterus and a fetid watery red-brown uterine discharge, associated with signs of systemic illness (decreased milk yield, dullness or other signs of toxemia) and fever > 39.5 degrees C, within 21 days after parturition. Animals that are not systemically ill, but have an abnormally enlarged uterus and a purulent uterine discharge detectable in the vagina, within 21 days post partum, may be classified as having clinical metritis. Clinical endometritis is characterised by the presence of purulent (> 50% pus) uterine discharge detectable in the vagina 21 days or more after parturition, or mucuopurulent (approximately 50% pus, 50% mucus) discharge detectable in the vagina after 26 days post partum. In the absence of clinical endometritis, a cow with subclinical endometritis is defined by > 18% neutrophils in uterine cytology samples collected 21-33 days post partum, or > 10% neutrophils at 34-47 days. Pyometra is defined as the accumulation of purulent material within the uterine lumen in the presence of a persistent corpus luteum and a closed cervix. In conclusion, we have suggested definitions for common postpartum uterine diseases, which can be readily adopted by researchers and veterinarians.

How to Improve Reproductive Efficacy from Now in Japan? Find out the Factors of Late Lactation to Predict Postpartum Reproductive Diseases

Reproductive efficiency and performance in dairy cattle has been declining over the last 20 years in Japan. Recently, this has resulted in serious problems in dairy herds. There have been changes in the animals themselves and in the animal's environment, e.g. the genetic potential for milk yield has improved, the herd size of dairy farms has been expanding, the housing system of dairy cattle has been changing from tie stall to free stall, and total mixed ratio (TMR) feeding systems have become widespread. It is not clear whether the animals have adapted adequately to these environmental changes. Up till now, reproductive management has been undertaken by monitoring animal performance and/or hormonal treatments, and this has resulted in acceptable reproductive performance. However, conception and pregnancy rates have continued to decline, and the calving to calving interval has continued to extend. Consequently, the average parity and the average age at culling in dairy cattle have been declining. The most common causes of culling in dairy cattle are reproductive disorders in Japan. Therefore, in future, prevention of reproductive disorders will be required for both reproductive efficiency and animal welfare. During late pregnancy and the transition from the pregnant, non-lactating state to the non-pregnant, lactating state, dramatic changes are occurring in the dam including an increase in the fetal-placental mass and calving. Thus, the demand for energy, protein and minerals by the conceptus increases, the space within the abdominal cavity and the rumen capacity decreases due to the increased volume of the conceptus, the local immunological relationship between the fetal and maternal placenta dramatically changes, and physiological homeostasis is activated to adapt to these changes. If cattle can't maintain homeostasis before calving, the incidence of reproductive diseases will be greatly increased. We have been examining reproductive, nutritional and immunological factors to predict the occurrence of reproductive disorders as early as possible and to develop strategies to prevent them. It is unlikely that all dairy farms in Japan will be able to improve reproductive performance with general advice, due to the wide variation in feeding systems and management in Japan. Therefore, specific advice needs to be tailored to each herd, based on management systems employed within each herd. We have proposed that it is important to identify common risk factors across herds, to use these factors as an index for disease control and reproductive management and finally to demonstrate the relationship between these factors and fundamental improvement of the reproductive efficiency. We propose this approach with the aim of providing a breakthrough in improving reproductive performance in dairy cattle in Japan. The focus of this review will be that such an approach is important for improvement of the reproductive efficiency in Japanese dairy cows.