Uterine infection alters the transcriptome of the bovine reproductive tract three months later

Graduate Student Literature Review: Implications of transition cow health for reproductive function and targeted reproductive management

Negative associations of health disorders with reproductive performance, often measured with pregnancy risk per artificial insemination (AI) or the risk of pregnancy loss, have been demonstrated extensively. Most studies investigated common clinical diseases but did not include subclinical disorders comprehensively. They often evaluated cows subjected to hormonal synchronization protocols for timed AI, limiting the ability to understand how disease may affect spontaneous reproductive function, which is essential for targeted management programs with selective hormonal intervention. It is plausible that metabolic and inflammatory disorders have short- and long-term detrimental effects on different features of reproductive function that result in or contribute to reduced fertility. These may include: 1) reestablishment of endocrine function to promote follicular growth and first ovulation postpartum, 2) corpus luteum (CL) function, 3) estrus expression, and 4) uterine environment, fertilization, and embryonic development. In this narrative literature review, we discuss insights and knowledge gaps linking health disorders with these processes of reproductive function. A growing set of observational studies with adequate internal validity suggest that these outcomes may be affected by metabolic and inflammatory disorders that are common in the early postpartum period. A better characterization of these risk factors in multi-site studies with greater external validity is warranted to develop decision-support tools to identify subgroups of cows that are more or less likely to be successful in targeted reproductive management programs.

Shifts in uterine microbiome associated with pregnancy outcomes at first insemination and clinical cure in dairy cows with metritis

Objectives were to assess differences in uterine microbiome associated with clinical cure and pregnancy outcomes in dairy cows treated for metritis. Cows with metritis (reddish-brownish, watery, and fetid vaginal discharge) were paired with cows without metritis based on parity and days postpartum. Uterine contents were collected through transcervical lavage at diagnosis, five days later following antimicrobial therapy (day 5), and at 40 days postpartum. Uterine microbiome was assessed by sequencing the V4 hypervariable region of the 16S rRNA gene. Although alpha-diversity based on Chao1, Shannon, and inverse Simpson indexes at diagnosis did not differ between cows with and without metritis, disease was associated with differences in beta-diversity. Prevalence of Porphyromonas, Bacteroides, and Veillonella was greater in cows with metritis. Streptococcus, Sphingomonas, and Ureaplasma were more prevalent in cows without metritis. Differences in beta-diversity between cows with and without metritis persisted on day 5. Uterine microbiome was not associated with clinical cure. Richness and alpha-diversity, but not beta-diversity, of uterine microbiome 40 days postpartum were associated with metritis and pregnancy. No relationship between uterine microbiome and pregnancy outcomes was observed. Results indicate that factors other than changes in intrauterine bacterial community underlie fertility loss and clinical cure in cows with metritis.

Molecular Mechanisms Associated with the Development of the Metritis Complex in Dairy Cattle

The metritis complex (MC), a group of post-partum uterine diseases, is associated with increased treatment costs and reduced milk yield and fertility. The goal of this study was to identify genetic variants, genes, or genomic regions that modulate MC disease. A genome-wide association study was performed using a single-locus mixed linear model of 1967 genotypes (624,460 SNPs) and metritis complex records. Then, in-silico functional analyses were performed to detect biological mechanisms and pathways associated with the development of MC. The ATP8A2, COX16, AMN, and TRAF3 genes, located on chromosomes 12, 10, and 21, were associated with MC at p ≤ 0.0001. These genes are involved in the regulation of cholesterol metabolism in the stromal tissue of the uterus, which can be directly associated with the mode of transmission for pathogens causing the metritis complex. The modulation of cholesterol abundance alters the efficiency of virulence factors and may affect the susceptibility of the host to infection. The SIPA1L1, DEPDC5, and RNF122 genes were also significantly associated with MC at p ≤ 0.0001 and are involved in the PI3k-Akt pathway, responsible for activating the autophagic processes. Thus, the dysregulation of these genes allows for unhindered bacterial invasion, replication, and survival within the endometrium.

Transcriptomics analysis of the bovine endometrium during the perioestrus period

During the oestrous cycle, the bovine endometrium undergoes morphological and functional changes, which are regulated by alterations in the levels of oestrogen and progesterone and consequent changes in gene expression. To clarify these changes before and after oestrus, RNA-seq was used to profile the transcriptome of oestrus-synchronized beef heifers. Endometrial samples were collected from 29 animals, which were slaughtered in six groups beginning 12 h after the withdrawal of intravaginal progesterone releasing devices until seven days post-oestrus onset (luteal phase). The groups represented proestrus, early oestrus, metoestrus and early dioestrus (luteal phase). Changes in gene expression were estimated relative to gene expression at oestrus. Ingenuity Pathway Analysis (IPA) was used to identify canonical pathways and functional processes of biological importance. A total of 5,845 differentially expressed genes (DEGs) were identified. The lowest number of DEGs was observed at the 12 h post-oestrus time point, whereas the greatest number was observed at Day 7 post-oestrus onset (luteal phase). A total of 2,748 DEGs at this time point did not overlap with any other time points. Prior to oestrus, Neurological disease and Organismal injury and abnormalities appeared among the top IPA diseases and functions categories, with upregulation of genes involved in neurogenesis. Lipid metabolism was upregulated before oestrus and downregulated at 48h post-oestrus, at which point an upregulation of immune-related pathways was observed. In contrast, in the luteal phase the Lipid metabolism and Small molecule biochemistry pathways were upregulated.

Microbial responses and changes in metabolic products in bovine uteri infected with Staphylococcus aureus

There is mounting evidence that the uterine microbiota has an important role in the pathogenesis of endometritis, with invasion of pathogenic bacteria being a main cause of uterine microbial imbalance. However, mechanisms of uterine microbiota resistance to pathogen invasion remain unclear. In this study, an intrauterine infusion of Staphylococcus aureus was used as a bovine endometritis model; it significantly increased abundance of pathogenic bacteria (Streptococcus, Helccoccus, Fusobacterium, and Escherichia-Shigella) and significantly decreased abundance of probiotics (Allstipes, Bacteroides, Phascolarctobacterium, Romboutsia, and Prevotella). In addition, the metabolite aloe-emodin was positively correlated with Prevotella and based on combined analyses of omics and probiotics, the presence of its metabolite aloe-emodin in the uterus at least partially resisted Staphylococcus aureus invasion. Therefore, Aloe-emodin has potential for regulating microbial structure and preventing endometritis.

Postpartum health is associated with detection of estrus by activity monitors and reproductive performance in dairy cows

The objective of this prospective observational study was to investigate associations of postpartum health with estrus detection (ED) by activity monitors and pregnancy outcomes in dairy cows. A total of 1,743 Holstein cows from 2 commercial dairy herds in Ontario, Canada were enrolled 3 wk before expected parturition and examined for health variables until 9 wk postpartum. Body condition score (BCS) and lameness were measured at 3 wk prepartum, and serum concentrations of total Ca, haptoglobin (Hp), and nonesterified fatty acids were measured at 2 and 6 ± 2 d in milk (DIM), and blood β-hydroxybutyrate (BHB) and metritis were assessed at 4, 8, 11, and 15 ± 2 DIM. Cows were examined for purulent vaginal discharge (PVD) and endometritis (ENDO) by endometrial cytology at wk 5, for lameness at wk 3 and 7, for BCS at wk 9 postpartum, and for time to onset of cyclicity by biweekly serum progesterone (P4) measurements. Additional disease data were obtained from farm records. Reproductive management for first AI was primarily based on ED by activity monitors until at least 75 DIM, and cows not detected in estrus were synchronized. Data were analyzed in multivariable logistic or Cox proportional hazards regression models including blood markers, health variables, potential covariates, and herd as a random effect. Estrus was detected in 77% of primiparous and 66% of multiparous cows between 50 or 55 DIM and 75 DIM. In 1,246 cows, the model-predicted probability of ED (percentage point difference) was lower in cows that had retained placenta (-14%), ENDO (-7%), PVD (-8%), delayed cyclicity (no P4 > 1 ng/mL by wk 9; -12%), or ≥0.5-point BCS loss (-14%) compared with cows without each of these risk factors, and it was negatively associated with blood BHB at 15 DIM. Considering only variables measured on farm (not requiring laboratory analysis), the probability of ED was lower (56 vs. 81%) in cows with >1 risk factor compared with cows without risk factors. The predicted probability of pregnancy at first artificial insemination (percentage point difference) was lower in cows that had ENDO (-7%) or PVD (-7%), and negatively associated with serum Hp at 6 ± 2 DIM. In cows detected in estrus by 75 DIM (n = 888), risk factors for reduced pregnancy rate by 250 DIM (adjusted hazard ratio (AHR); 95% confidence intervals) included difficult calving (AHR: 0.67; 0.45 to 1.00), metritis (AHR: 0.79; 0.61 to 1.01), PVD (AHR: 0.79; 0.65 to 0.97), or lameness (AHR: 0.79; 0.62 to 1.01), and it was negatively associated with serum Hp at 6 ± 2 DIM. Monitoring postpartum health may be used to identify cows that are more or less likely to be detected in estrus by activity monitors and to become pregnant in a timely manner. This would support a selective reproductive management program with targeted interventions.

Associations between the postpartum uterine and vaginal microbiota and the subsequent development of purulent vaginal discharge vary with dairy cow breed and parity

The objective of this study was to characterize the species composition and functional potential of the vaginal and uterine microbiota at 1 wk postpartum in dairy cows diagnosed with or without purulent vaginal discharge (PVD) at 3 wk postpartum. The hypothesis was that differences in the vaginal and uterine microbiota between cows diagnosed with (PVD+) or without (PVD-) PVD were dependent on parity and breed. Cytobrush samples of the vagina and uterus were collected at 1 wk postpartum from 36 Holstein-Friesian (7 primiparous and 29 multiparous) and 29 Jersey (10 primiparous and 19 multiparous) cows. Microbial DNA was isolated from each sample and processed for shotgun metagenomic sequencing. The odds of multiparous cows being diagnosed as PVD+ was less compared with primiparous cows (OR = 0.21). Neither the α-diversity nor β-diversity of the uterine and vaginal microbiota were associated with PVD but the β-diversity was different between breeds and between parities. In the vagina of primiparous cows, differences in the microbiota of PVD- and PVD+ cows were minor, but the microbiota of multiparous PVD+ cows had greater relative abundance of Fusobacterium necrophorum, Trueperella pyogenes, Porphyromonas levii, and greater functional potential for amino acid and protein synthesis, energy metabolism, and growth compared with PVD- cows. The uterus of primiparous PVD+ cows had lesser relative abundance of Bacteroides heparinolyticus compared with PVD- cows. In the uterine microbiota, differences included greater functional potential for cellulose biosynthesis and fucose catabolism in multiparous PVD+ cows compared with PVD- cows. In the uterine microbiota of primiparous PVD+ cows, the functional potential for gram-negative cell wall synthesis and for negative regulation of tumor necrosis factor signaling was lesser compared with multiparous PVD+ cows. In the vagina of Holstein-Friesian PVD+ cows, the relative abundance of Caviibacter abscessus was greater whereas in the vagina of Jersey PVD+ cows the relative abundance of Catenibacterium mitsuokai, Finegoldia magna, Klebsiella variicola, and Streptococcus anginosus was greater compared with PVD- cows. In the uterine microbiota of Holstein-Friesian cows, the functional potential for spermidine biosynthesis was reduced compared with PVD- cows. In summary, differences in the species composition and functional potential of the vaginal and uterine microbiota between PVD- and PVD+ cows were dependent on parity and breed. The findings suggest that alternative strategies may be required to treat PVD for different parities and breeds of dairy cow.

Induced endometrial inflammation compromises conceptus development in dairy cattle†

Endometrial inflammation is associated with reduced pregnancy per artificial insemination (AI) and increased pregnancy loss in cows. It was hypothesized that induced endometritis alters histotroph composition and induces inflammatory signatures on conceptus that compromise development. In Experiment 1, lactating cows were assigned to control (CON; n = 23) or to an intrauterine infusion of Escherichia coli and Trueperella pyogenes (ENDO; n = 34) to induce endometritis. Cows received AI 26 days after treatment, and the uterine fluid and conceptuses were collected on day 16 after AI. In Experiment 2, Holstein heifers were assigned to CON (n = 14) or ENDO (n = 14). An embryo was transferred on day 7 of the estrous cycle, and uterine fluid and conceptuses were recovered on day 16. Composition of histotroph and trophoblast and embryonic disc gene expression were assessed. Bacterial-induced endometritis in lactating cows altered histotroph composition and pathways linked to phospholipid synthesis, cellular energy production, and the Warburg effect. Also, ENDO reduced conceptus length in cows and altered expression of genes involved in pathogen recognition, nutrient uptake, cell growth, choline metabolism, and conceptus signaling needed for maternal recognition of pregnancy. The impact of ENDO was lesser on conceptuses from heifers receiving embryo transfer; however, the affected genes and associated pathways involved restricted growth and increased immune response similar to the observed responses to ENDO in conceptuses from lactating cows. Bacterial-induced endometrial inflammation altered histotroph composition, reduced conceptus growth, and caused embryonic cells to activate survival rather than anabolic pathways that could compromise development.

Comparison between trans-vaginal and recto-vaginal techniques for transferring embryos in the dromedary camels

The present study was conducted in two breeding seasons to compare the effect of two non-surgical techniques for embryo deposition intrauterine, trans-vaginal (TV) versus recto-vaginal (RV) techniques, on the pregnancy rate and early pregnancy loss (EPL) in dromedary camels. Embryos were collected from 70 donors and transferred to 210 recipients by TV (n = 256 transfers) or RV technique (n = 186 transfers). Pregnancy diagnosis was conducted on Day 10 after embryo transfer (ET) by using the progesterone-ELISA test and by trans-rectal ultrasonography at Day 60 of gestation. EPL was calculated as the recipients that were diagnosed pregnant on Day 10 post-ET and lost their pregnancy between Days 20-60 of their gestation. Using the RV technique in ET of a single embryo showed higher pregnancy rates at Day 19, especially with the embryos of folded, semi-transparent shapes, or those collected after superovulation with the recovery of >4 embryos per flush. While, the pregnancy rates at 60 days showed increases after ET with the RV technique of single, folded, transparent, and semi-transparent, medium-size embryos and/or those collected after superovulation with any number of the recovered embryos than those transferred by the TV technique. The rate of EPL was increased when the TV technique was used for ET of single, spherical, folded, semi-transparent, medium-sized embryos and those collected without or with the superovulation and recovery of >4 embryos per flush. In conclusion, using the RV technique to deposit the embryos intrauterine improves the pregnancy rate and reduces EPL compared to the TV technique.

Review: Postpartum reproductive disease and fertility in dairy cows

This paper reviews recent data and concepts on metritis, purulent vaginal discharge (PVD), and endometritis in dairy cows and the ways in which these diseases affect reproductive performance. Metritis is characterized by fetid discharge from the uterus, with or without fever. Purulent vaginal discharge describes exudate that is >50% pus that may be attributable to uterine infection or cervicitis. Endometritis is inflammation of the uterus diagnosed by endometrial cytology with a proportion of neutrophils (typically ≥5%) that is associated with impaired fertility. Metritis and PVD are associated with uterine bacterial dysbiosis: changes in the microbiota to lesser diversity and greater abundance of pathogens, especially Gram-negative anaerobic bacteria, and Trueperella pyogenes in the case of PVD. Metritis is justifiably treated with approved antibiotics but criteria for more selective treatment without loss of performance are emerging. Purulent vaginal discharge is not synonymous with clinical endometritis, and greater precision in terminology is warranted. PVD is likely under-diagnosed and represents an opportunity for improved management in many herds. Endometritis seems in many cases to reflect persistent, dysregulated inflammation, for which the inciting cause is unclear. Postpartum uterine infection and inflammation have harmful effects on oocytes, embryo development, and the endometrium for at least three months, even if the disease is apparently resolved. Emerging concepts of the resolution and regulation of inflammation are promising for the improvement of prevention and therapy of endometritis.

Induced endometritis in early lactation compromises production and reproduction in dairy cows

Objectives of this experiment were to study the effect of infusing utero-pathogenic bacteria to induce endometrial inflammation on productive performance in early lactation and subsequent reproduction. Although endometritis is associated with perturbed reproduction, numerous factors may contribute to the observed association. It was hypothesized that induced endometrial inflammation, resulting in localized and systemic inflammatory responses, compromises production and reproduction. Holstein cows without clinical disease and with less than 18% polymorphonuclear leukocytes (PMN) in endometrial cytology on d 31 ± 3 postpartum had their estrous cycle synchronized. Cows were blocked by parity and genomic breeding value for cow conception rate and, within block, assigned randomly to remain as untreated controls (CON; n = 37) or to receive an intrauterine infusion of 5.19 × 10⁸ cfu Escherichia coli and 4.34 × 10⁸ cfu Trueperella pyogenes during the luteal phase to induce endometrial inflammation (INF; n = 48). Endometrial cytology was taken on d 2 and 7 after treatment to evaluate the proportion of PMN. Rectal temperature, dry matter intake, and yields of milk and components were measured in the first 7 d after treatment. Blood serum was analyzed for concentration of haptoglobin. Leukocytes were isolated from blood on d 2 and 7 after treatment and on d 19 after artificial insemination (AI) and mRNA was quantified for a select group of genes. Cows received AI and reproduction was followed for 300 d postpartum. Bacterial infusion induced endometrial inflammation with increased proportions of PMN in the endometrial cytology on d 2 (4.4 ± 0.7 vs. 26.3 ± 2.8%) and 7 (10.9 ± 1.7 vs. 17.4 ± 2.1%) after treatment, resulting in increased mean prevalence of subclinical endometritis (>10% PMN; 23.3 ± 6.3 vs. 80.9 ± 5.1%). Rectal temperature did not differ between CON and INF, but the concentration of haptoglobin in serum tended to increase in INF compared with CON (113 ± 14 vs. 150 ± 16 µg/mL). Induced endometrial inflammation reduced yields of milk (44.9 ± 0.8 vs. 41.6 ± 0.8 kg/d), protein (1.19 ± 0.03 vs. 1.12 ± 0.03 kg/d), and lactose (2.17 ± 0.04 vs. 2.03 ± 0.04 kg/d) and tended to reduce dry matter intake (20.7 ± 0.5 vs. 19.4 ± 0.6 kg/d) in the first 7 d after treatment. Indeed, the reduction in milk yield lasted 4 wk. However, treatment did not affect yields of energy-corrected milk or fat because treatment with INF increased the concentration of fat in milk (3.54 ± 0.10 vs. 3.84 ± 0.10%). Induced endometrial inflammation reduced pregnancy per AI at all inseminations (33.4 ± 5.1 vs. 21.6 ± 3.7%) and the hazard of pregnancy (0.61; 95% CI = 0.36-1.04), which extended the median days open by 24 d. Blood leukocytes from INF cows had increased mRNA expression of the pro-inflammatory gene IL1B on d 2 and 7 after treatment, but reduced expression of the IFN-stimulated genes ISG15 and MX2 on d 19 after AI. Induced endometrial inflammation depressed production and caused long-term negative effects on reproduction in lactating dairy cows.

Lipopolysaccharide alters CEBPβ signaling and reduces estradiol production in bovine granulosa cells

Background

Bacterial infection of the uterus in postpartum dairy cows limits ovarian follicle growth, reduces blood estradiol concentrations, and leads to accumulation of bacterial lipopolysaccharide (LPS) in ovarian follicular fluid. Although treating granulosa cells with LPS in vitro decreases the expression of the estradiol synthesis enzyme CYP19A1 and reduces estradiol secretion, the molecular mechanisms are unclear. The transcription factor CCAAT enhancer binding protein beta (CEBPβ) not only facilitates the transcription of LPS regulated cytokines, but also binds to the promoter region of CYP19A1 in humans, mice, and buffalo. We hypothesized that LPS alters CEBPβ signaling to reduce CYP19A1 expression, resulting in decreased estradiol secretion.

Methods

Bovine granulosa cells were isolated from small/medium or large follicles and treated with LPS in the presence of FSH and androstenedione for up to 24 h.

Results

Treatment with LPS increased CXCL8 and IL6 gene expression and reduced estradiol secretion in granulosa cells from both small/medium and large follicles. However, LPS only reduced CYP19A1 expression in granulosa cells from large follicles. Treatment with LPS increased CEBPB expression and reduced CEBPβ nuclear localization in granulosa cells from small/medium follicles, but not granulosa cells from large follicles.

Conclusions

Although LPS reduces estradiol synthesis in bovine granulosa cells, the effects of LPS on CYP19A1 and CEBPβ are dependent on follicle size.

Favored single nucleotide variants identified using whole genome Re-sequencing of Austrian and Chinese cattle breeds

Cattle have been essential for the development of human civilization since their first domestication few thousand years ago. Since then, they have spread across vast geographic areas following human activities. Throughout generations, the cattle genome has been shaped with detectable signals induced by various evolutionary processes, such as natural and human selection processes and demographic events. Identifying such signals, called selection signatures, is one of the primary goals of population genetics. Previous studies used various selection signature methods and normalized the outputs score using specific windows, in kbp or based on the number of SNPs, to identify the candidate regions. The recent method of iSAFE claimed for high accuracy in pinpointing the candidate SNPs. In this study, we analyzed whole-genome resequencing (WGS) data of ten individuals from Austrian Fleckvieh (Bos taurus) and fifty individuals from 14 Chinese indigenous breeds (Bos taurus, Bos taurus indicus, and admixed). Individual WGS reads were aligned to the cattle reference genome of ARS. UCD1.2 and subsequently undergone single nucleotide variants (SNVs) calling pipeline using GATK. Using these SNVs, we examined the population structure using principal component and admixture analysis. Then we refined selection signature candidates using the iSAFE program and compared it with the classical iHS approach. Additionally, we run Fst population differentiation from these two cattle groups. We found gradual changes of taurine in north China to admixed and indicine to the south. Based on the population structure and the number of individuals, we grouped samples to Fleckvieh, three Chinese taurines (Kazakh, Mongolian, Yanbian), admixed individuals (CHBI_Med), indicine individuals (CHBI_Low), and a combination of admixed and indicine (CHBI) for performing iSAFE and iHS tests. There were more significant SNVs identified using iSAFE than the iHS for the candidate of positive selection and more detectable signals in taurine than in indicine individuals. However, combining admixed and indicine individuals decreased the iSAFE signals. From both within-population tests, significant SNVs are linked to the olfactory receptors, production, reproduction, and temperament traits in taurine cattle, while heat and parasites tolerance in the admixed individuals. Fst test suggests similar patterns of population differentiation between Fleckvieh and three Chinese taurine breeds against CHBI. Nevertheless, there are genes shared only among the Chinese taurine, such as PAX5, affecting coat color, which might drive the differences between these yellowish coated breeds, and those in the greater Far East region.

Effect of retained placenta and clinical mastitis on reproduction parameters, immune response, and steroidogenic receptors gene expression in postpartum crossbred dairy cows

The purpose of this study was to evaluate the effect of retained placenta (RP) and clinical mastitis (CM) on the reproductive efficiency of crossbred dairy cows during the postpartum period and the effect in some innate immune system indicators. For this, two experiments were carried out. In the first, a total of 232 cows were evaluated and divided as: healthy control (n = 184), RP (n = 22), and CM (n = 26) groups. The RP and CM was evaluated until 30 days postpartum (DPP) and reproductive rates were measured. In experiment 2, cows were divided in control (n = 10), RP (n = 10), and CM (n = 30) groups. Between 40 and 50 DPP, clinical, gynecological examination and endometrial cytobrush were performed to evaluate subclinical endometritis (SE) and gene expression of interleukins 1β (IL-1β) and 6 (IL-6), chemokine ligand 5 (CCL5), estrogen α (ESR1), and progesterone (PGR) receptors by qRT-PCR analysis. In experiment 1, the conception rate at 1st artificial insemination (AI) was lower in RP and CM groups and pregnancy rate at 150 days decreased in CM group. Calving-to-1st AI interval and days open were shorter in healthy cows. In experiment 2, the occurrence of SE was 26.7% and higher in RP and CM groups. The expression of IL-1β increased in RP and CM groups, while IL-6 was less expressed in RP group. The CCL5, ESR1, and PGR were similar between groups. In conclusion, cows with RP and CM had their reproductive efficiency negatively affected and had they initial pro-inflammatory response improved by the increase of IL-β.

The endometrial transcriptomic response to pregnancy is altered in cows after uterine infection

Pregnancy induces changes in the transcriptome of the bovine endometrium from 15 days after insemination. However, pregnancy is less likely to occur if cows had a postpartum bacterial infection of the uterus, even after the resolution of disease. We hypothesized that uterine bacterial infection alters the endometrial transcriptomic signature of pregnancy after the resolution of disease. To examine the endometrial transcriptomic signature of pregnancy, cows were inseminated 130 days after intrauterine infusion of pathogenic Escherichia coli and Trueperella pyogenes, subsequently endometrium was collected 16 days after insemination for RNA sequencing. We found 171 pregnancy regulated genes in cows 146 days after bacterial infection. When comparing our findings with previous studies that described the endometrial transcriptomic signature of pregnancy in healthy cows, 24 genes were consistently differentially expressed in pregnancy, including MX1, MX2 and STAT1. However, 12 pregnancy regulated genes were found only in the endometrium of healthy cows, including ISG15 and TRANK1. Furthermore, 28 pregnancy regulated genes were found only in the endometrium of cows following bacterial infection and these were associated with altered iNOS, TLR, and IL-7 signaling pathways. Although 94 predicted upstream regulators were conserved amongst the studies, 14 were found only in the endometrium of pregnant healthy cows, and 5 were found only in cows following bacterial infection, including AIRE, NFKBIA, and DUSP1. In conclusion, there were both consistent and discordant features of the endometrial transcriptomic signature of pregnancy 146 days after intrauterine bacterial infusion. These findings imply that there is an essential transcriptomic signature of pregnancy, but that infection induces long-term changes in the endometrium that affect the transcriptomic response to pregnancy.

Failure of clinical cure in dairy cows treated for metritis is associated with reduced productive and reproductive performance

Objectives were to assess reproductive and productive outcomes associated with failure of clinical cure in dairy cows diagnosed with metritis following antimicrobial therapy. This retrospective cohort study included data from 3 experiments performed in 5 dairies. Metritis was characterized by the presence of watery, fetid, reddish-brownish vaginal discharge within 21 DIM (study d 0). Cows not diagnosed with metritis (i.e., cows may have had other diseases postpartum; NoMT; n = 1,194) were paired based on lactation number and calving date. All cows with metritis received antimicrobial therapy (ampicillin or ceftiofur). Clinical cure was evaluated on d 10 based on vaginal discharge score, and cows were categorized as cured (MTC; n = 1,111) or not cured (MTnoC; n = 299). Purulent vaginal discharge (28 ± 3 or 32 ± 3 DIM), cytological endometritis (35 ± 3 or 39 ± 3 DIM), and estrous cyclicity (50 ± 3 and 64 ± 3, 36 ± 3 and 50 ± 3, or 37 ± 5 and 51 ± 5 DIM) were evaluated in subgroups of cows. Proportions of cows with purulent vaginal discharge and cytological endometritis were greatest for MTnoC (91.7 and 91.4%), intermediate for MTC (74.0 and 73.3%), and smallest for NoMT (38.1 and 36.4%). Proportion of cyclic cows was smaller for MTnoC compared with MTC and NoMT (62.0, 71.0, and 71.0%). Pregnancy per artificial insemination following first service was smaller for cows with metritis compared with their counterparts with no metritis (NoMT = 28.1, MTC = 26.1, MTnoC = 22.0%). Pregnancy loss tended to be greater for MTnoC compared with MTC (NoMT = 11.5, MTC = 11.1, MTnoC = 18.4%). Hazard of pregnancy by 300 DIM was smallest for MTnoC, intermediate for MTC, and greatest for NoMT. Death by 60 DIM (3.9, 1.1, and 0.6%) and removal from herd by 300 DIM (26.3, 17.4, and 15.4%) were greatest for MTnoC compared with MTC and NoMT, respectively. Milk production among multiparous cows was smaller for MTnoC compared with MTC and NoMT in the first 10 mo postpartum, whereas MTC produced less milk compared with NoMT only during the first 2 mo postpartum (NoMT = 42.0 ± 0.22, MTC = 40.6 ± 0.28, MTnoC = 37.7 ± 0.54 kg/d). Failure of clinical cure was not associated with milk yield in primiparous cows (NoMT = 35.2 ± 0.31, MTC = 33.9 ± 0.31, MTnoC = 35.0 ± 0.52 kg/d). Cows diagnosed with metritis that do not undergo clinical cure by 10 d of onset of antimicrobial therapy have impaired reproductive performance, reduced milk production, and increased risk of leaving the herd.

Inflammatory diseases in dairy cows: Risk factors and associations with pregnancy after embryo transfer

The objectives of the present prospective cohort study were to identify risk factors for inflammatory diseases in Holstein-Gyr crossbred dairy cows and characterize the associations of those diseases with pregnancy per embryo transfer (ET). Diseases were diagnosed in the first 60 d postpartum in 252 primiparous and 481 multiparous cows. Uterine diseases (UTD) included retained placenta, metritis, clinical endometritis, and subclinical endometritis. Nonuterine diseases (NUTD) included mastitis, lameness, pneumonia, and displaced abomasum. Blood was sampled on d 0, 1, and 2 postpartum and analyzed for concentrations of haptoglobin, fatty acids, total Ca (tCa), P, and Mg, and again on d 8 postpartum and analyzed for concentration of β-hydroxybutyrate. The association between concentrations of metabolites in serum and inflammatory diseases was determined. Cows received a timed ET program starting 28 ± 3 d postpartum with first ET at 46 ± 3 d postpartum using fresh in vitro-produced embryos. Pregnancy was diagnosed on d 31 and 59 of presumptive gestation. Overall, 63.3% of the cows were diagnosed with UTD and 20.6% with NUTD. The risk factors for UTD included season of calving, parity group, calving problems, days with subclinical hypocalcemia, and serum concentrations of haptoglobin and Mg, whereas the risk factors for NUTD were parity group and serum Mg concentration. Cows that developed UTD had increased concentrations of haptoglobin on d 2 and fatty acids on d 1 and 2, and reduced concentrations of tCa on d 1 and 2 and of P and Mg on d 2 postpartum compared with cows without UTD. Cows that developed NUTD had increased concentrations of fatty acids on d 0 to 2 postpartum, and decreased concentrations of tCa and P on d 0 and 1, and of Mg on d 1 and 2 postpartum compared with cows without NUTD. Cows that developed NUTD had a 340-kg reduction in milk yield in the first 60 d postpartum. Inflammatory diseases were associated with lesser body condition score and increased loss of body condition in the first 70 d postpartum. Maintenance of pregnancy after ET was reduced in UTD cows following the first (41.7 vs. 25.4%) or all ET (46.4 vs. 36.2%), whereas maintenance of pregnancy was reduced in NUTD cows only at the second ET (39.0 vs 25.9%). The reduced pregnancy maintenance in UTD cows combined with a reduced 21-d service rate (61.9 vs. 54.8%) decreased the 21-d cycle pregnancy rate (28.6 vs. 19.9%) and the hazard of pregnancy to 300 d postpartum by 35%, resulting in an extra 32 d open. In conclusion, inflammatory diseases depressed fertility in dairy cows receiving ET, with the greatest impact observed in UTD cows. This suggests that local inflammation of the uterus impairs maintenance of pregnancy in dairy cows following ET.

Recent advances and future directions for uterine diseases diagnosis, pathogenesis, and management in dairy cows

Researchers, veterinarians, and farmers' pursuit of a consistent diagnosis, treatment, and prevention of uterine diseases remains challenging. The diagnosis and treatment of metritis is inconsistent, a concerning situation when considered the global threat of antimicrobial resistance dissemination. Endometritis is an insidious disease absent on routine health programs in many dairy farms and from pharmaceutical therapeutics arsenal in places like the US market. Conversely, a multitude of studies advanced the understanding of how uterine diseases compromise oocyte, follicle, and embryo development, and the uterine environment having long-lasting effects on fertility. The field of uterine disease microbiome also experienced tremendous progress and created opportunities for the development of novel preventives to improve the management of uterine diseases. Activity monitors, biomarkers, genomic selection, and machine learning predictive models are other innovative developments that have been explored in recent years to help mitigate the negative impacts of uterine diseases. Albeit novel tools such as vaccines for metritis, immune modulators, probiotics, genomic selection, and selective antimicrobial therapy are promising, further research is warranted to implement these technologies in a systematic and cost-effective manner.