The association of cow-related factors assessed at metritis diagnosis with metritis cure risk, reproductive performance, milk yield, and culling for untreated and ceftiofur-treated dairy cows

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.

Genetic analysis of health traits and their associations with longevity, fertility, production, and conformation traits in Holstein cattle

Health traits have high economic values in dairy cattle breeding, which can cause considerable financial loss through involuntary culling. In this study, fourteen health traits were analysed, including five composite health traits: reproductive disorders, udder health (UH), digestive disorders, metabolic disorders, locomotory diseases (LD), and nine independent health traits: gestation disorders and peripartum disorders, irregular estrus cycle and sterility, metritis (ME), mastitis (MA), abomasal displacement (AD), enteritis (EN), and ketosis, claw diseases (CD), laminitis complex. This study analysed variance components for health traits through both single and bivariate repeatability animal models. All health traits showed low heritability, ranging from 0.001 to 0.025. Most of the health traits in five categories showed negative genetic correlations, ranging from -0.012 (CD and EN) to -0.634 (ME and EN). Strong positive genetic correlations appeared within the same category, ranging from 0.469 (EN and AD) to 0.994 (UH and MA, LD and CD). Furthermore, approximate genetic correlations were evaluated between health traits and routinely collected traits (longevity, fertility, production, and conformation). In general, the low to moderate approximate genetic correlations were estimated between health traits and routinely collected traits. The estimated correlations between health traits and longevity, fertility, production, and conformation traits could provide an indirect reference for disease-resistance breeding in Holstein cattle.

Effect of rumen-protected choline on dairy cow metabolism, immunity, lactation performance, and vaginal discharge microbiome

Rumen-protected choline (RPC) promotes benefits in milk production, immunity, and health in dairy cows by optimizing lipid metabolism during transition period management and early lactation. However, the RPC success in dairy cows depends on choline bioavailability, which is affected by the type of protection used in rumen-protected choline. Therefore, our objectives were to determine the effects of a novel RPC on dry matter intake (DMI), identify markers of metabolism and immunity, and evaluate lactation performance. Dry Holstein (n = 48) cows at 245 ± 3 d of gestation were blocked by parity and assigned to control or RPC treatment within each block. Cows enrolled in the RPC treatment received 15 g/d of CholiGEM (Kemin Industries, Cavriago RE, Italy) from 21 d prepartum and 30 g/d of CholiGEM from calving to 21 d postpartum. During the transition period, DMI was measured daily, and blood was sampled weekly for energy-related metabolites such as β-hydroxybutyrate (BHB), glucose, and nonesterified fatty acids (NEFA), as well as immune function markers such as haptoglobin (Hp) and lipopolysaccharide-binding protein (LPB). Vaginal discharge samples were collected at the calving and 7 d postpartum and stored in microcentrifuge tubes at -80°C until 16S rRNA sequencing. The main responses of body condition score, body weight, DMI, milk yield, milk components, and immune function markers were analyzed using the GLIMMIX procedure of SAS with the effects of treatment, time, parity, and relevant covariates added to the models. The relative abundance of microbiome α-diversity was evaluated by 3 indexes (Chao1, Shannon, and Simpson) and β-diversity by principal coordinate analysis and permutational multivariate ANOVA. We found no differences in DMI in the pre- and postpartum periods. Cows fed RPC increased the yields of energy- and 3.5% fat-corrected milk and fat yield in primiparous and multiparous cows, with an interaction between treatment and parity for these lactation variables. However, we found no differences in milk protein and lactose up to 150 DIM between treatments. Glucose, NEFA, and BHB had no differences between the treatments. However, RPC decreased BHB numerically (control = 1.07 ± 0.13 vs. RPC = 0.63 ± 0.13) in multiparous on the third week postpartum and tended to reduce the incidence of subclinical ketosis (12.7% vs. 4.2%). No effects for Hp and LPB were found in cows fed RPC. Chao1, Shannon, and Simpson indexes were lower at calving in the RPC treatment than in the Control. However, no differences were found 7 d later for Chao1, Shannon, and Simpson indexes. The vaginal discharge microbiome was altered in cows fed RPC at 7 d postpartum. Fusobacterium, a common pathogen associated with metritis, was reduced in cows fed RPC. Rumen-protected choline enhanced lactation performance and health and altered the vaginal discharge microbiome which is a potential proxy for uterine healthy in dairy cows. The current study's findings corroborate that RPC is a tool to support adaptation to lactation and shed light on opportunities for further research in reproductive health.

Herd-level associations between the proportion of elevated prepartum nonesterified fatty acid concentrations and postpartum diseases, reproduction, or culling on dairy farms

The objectives of this herd-level prospective observational cohort study were to describe the proportion of cows with elevated prepartum nonesterified fatty acid concentrations (PropElevNEFA) in dairy herds and to assess the herd-level associations between PropElevNEFA and postpartum diseases, reproductive performance, and culling. From November 2018 to December 2020, a convenience sample of 49 herds was enrolled in this study. Blood sampling (16 to 29 cows per herd) was performed during the week before and during the 2 wk following calving to quantify the concentration of nonesterified fatty acids (NEFA) and β-hydroxybutyrate acids (BHBA), respectively. Elevated NEFA was defined as ≥280 µmol/L and hyperketonemia as BHBA ≥1.4 mmol/L. Retained placenta, metritis, purulent vaginal discharge, endometritis, and mastitis were diagnosed on-farm following standardized definitions, and success at first artificial insemination (AI) and culling events were recorded. The associations between PropElevNEFA and each individual disease, success at first AI, and culling were evaluated using Bayesian aggregated binomial regression models with weakly informative priors, from the which odds ratio (OR) and the 95% credible intervals (BCI) were obtained. A total of 981 cows were included in the statistical analyses representing 16 to 29 (median = 19) cows per herd. Cows were enrolled in the prepartum period of their first to tenth (median = third) lactation, and 41% of them had an elevated prepartum NEFA concentration. At the herd level, PropElevNEFA varied between 11% and 78% (median = 39%). The odds of metritis (OR = 1.37, 95% BCI = 1.13-1.67) increased for every 10-point increase in PropElevNEFA, whereas the odds of success at first AI decreased (OR = 0.69, 95% BCI = 0.59-0.80). The PropElevNEFA was not associated with the other tested diseases or culling. Our results suggest that the herd-level proportion of cows having elevated prepartum NEFA concentrations is associated with metritis and poor success at first AI in dairy herds.

A randomized controlled trial evaluating the efficacy of systemic ceftiofur administration for metritis therapy in dairy cows and the effect of metritis cure on economically important outcomes

The main objective of this study was to evaluate the effect of ceftiofur on metritis cure, milk yield, reproductive performance, and culling up to 300 DIM. The secondary objective was to evaluate the effect of metritis cure at 5 (ECURE) and 14 (LCURE) d after diagnosis on milk production, reproduction, and culling. A total of 422 Holstein cows diagnosed with metritis from 4 herds located in TX, CA, and FL were enrolled in a randomized clinical trial. Cows diagnosed with metritis (fetid, watery, reddish/brownish uterine discharge) were blocked by herd and parity and were randomly allocated to receive systemic administration of ceftiofur (CEF) or to remain untreated (CON). In addition, 399 non-metritic cows (NMET) were included for comparison purposes. Metritis cure was evaluated at 5 and 14 d after diagnosis and was defined as the absence of metritis clinical signs. Logistic regression models were fitted to the data to assess the effect of treatment on metritis cure. Milk yield was analyzed using a mixed linear model, while logistic regression, Cox proportional hazard and Kaplan-Meier survival analysis models were fitted to culling and reproduction data. Cows treated with CEF had 1.86 (95% CI: 1.22 - 2.81) and 1.68 (95% CI: 1.02 - 2.75) greater odds of being cured than CON cows at 5 and 14 d after diagnosis, respectively. No effect of CEF was observed for milk yield; however, NMET cows had greater milk yield compared with metritic cows (CEF = 36.0, 95% CI = 33.8 - 38.1; CON = 36.1, 95% CI = 33.9 - 38.2; NMET = 36.9 kg/d, 95% CI = 34.8 - 39.4). Likewise, no effect of CEF was observed on reproductive performance and culling. Nonetheless, the likelihood of conceiving for NMET cows was 1.72 (95% CI = 1.41 - 2.12) and 1.64 (95% CI = 1.33 - 2.00) times greater than for CEF and CON cows, respectively. Ceftiofur-treated and CON cows had 2.93 (95% CI = 1.90 - 4.51) and 2.37 (95% CI = 1.51 - 3.71) greater hazard of culling compared with NMET, respectively. Regardless of treatment, no differences between ECURE and LCURE were observed on milk yield, reproduction, and culling throughout the entire lactation, but cows that cured at 5 or 14 d after diagnosis had greater milk production in the first 60 DIM compared with cows that did not cure (NCURE). Cows in ECURE and LCURE also had a 1.59 (95% CI = 1.16 - 2.16) and 1.49 (95% CI = 1.08 - 2.05) greater hazard of pregnancy and 0.43 (95% CI = 0.26-0.71) and 0.56 (95% CI = 0.34-0.92) hazard of culling compared with NCURE. Ceftiofur therapy increased metritis cure, but benefits to productivity and longevity were not observed. Also, cows that fail to cure have impaired lactation performance, but no differences regarding timing of cure were observed.

Evaluating differences in milk production, reproductive performance, and survival associated with vaginal discharge characteristics and fever in postpartum dairy cows

The objective was to assess differences in productive and reproductive performance, and survival associated with vaginal discharge characteristics and fever in postpartum dairy cows located in Western and Southern states of the U.S.A. This retrospective cohort study included data from 3 experiments conducted in 9 dairies. Vaginal discharge was evaluated twice within 12 DIM and scored on a 5-point scale. The highest score observed for each cow was used for group assignment (VD group) as follows: VD 1 and 2 (VD 1/2; n = 1,174) = clear mucus/lochia with or without flecks of pus; VD 3 (n = 1,802) = mucopurulent with < 50% pus; VD 4 (n = 1,643) = mucopurulent with ≥50% of pus or non-fetid reddish/brownish mucous, n = 1,643; VD 5 = fetid, watery, and reddish/brownish, n = 1,800. All VD 5 cows received treatment according to each herd's protocol. Rectal temperature was assessed in a subset of VD 5 cows, and subsequently divided into Fever (rectal temperature ≥39.5°C; n = 334) and NoFever (n = 558) groups. A smaller proportion of cows with VD 5 (67.6%) resumed ovarian cyclicity compared with VD 1/2 (76.2%) and VD 4 (72.9%) cows; however, a similar proportion of VD5 and VD 3 (72.6%) cows resumed ovarian cyclicity. A smaller proportion of VD 5 (85.8%) cows received at least one artificial insemination (AI) compared with VD 1/2 (91.5%), VD 3 (91.0%), or VD 4 (91.6%) cows. Although we did not detect differences in pregnancy at first AI according to VD, fewer cows with VD 5 (64.4%) were pregnant at 300 DIM than cows with VD 1/2 (76.5%), VD 3 (76.2%), or VD 4 (74.7%). Hazard of pregnancy by 300 DIM was smaller for VD 5 compared with VD 1/2, VD 3, or VD 4 cows. A greater proportion of VD 5 cows were removed from the herd within 300 DIM compared with other VD groups. There was 760 kg lesser milk production within 300 DIM for VD 5 compared with VD 2, VD 3, and VD 4, whereas VD 2, VD 3, and VD 4 had similar milk production. We did not detect an association between fever at diagnosis of VD 5 and reproductive performance or milk production. A greater proportion of VD 5 cows without fever were removed from the herd by 300 DIM compared with VD 5 cows with fever. Differences in productive and reproductive performance, and removal of the herd were restricted to fetid, watery, and reddish/brownish vaginal discharge, which was independent of fever.

Predictive models for metritis cure using farm-collected data, metabolic and inflammation biomarkers, and hemogram variables measured at diagnosis

Our objective was to evaluate the accuracy of predictive models for metritis spontaneous cure (SC) and cure among ceftiofur-treated cows using farm collected data only, and with the addition of hemogram variables and circulating concentration of metabolites, minerals, and biomarkers of inflammation measured at time of diagnosis. Data related to parity, calving related issues, body condition score (BCS), rectal temperature (RT), and days in milk (DIM) at metritis diagnosis were collected from a randomized clinical trial that included 412 metritic cows from 4 herds in TX, CA, and FL. Metritis was defined as the presence of red-brownish, watery, and fetid vaginal discharge, while cure was defined as the absence of metritis 14 d after initial diagnosis. Cows were randomly allocated to receive systemic ceftiofur therapy (2 subcutaneous doses of 6.6 mg/kg of ceftiofur crystalline-free acid on the day of diagnosis and 3 d later; CEF) or to remain untreated (CON). At enrollment (day of metritis diagnosis), blood samples were collected and submitted to cell blood count (CBC) and processed for the measurement of 13 minerals and biomarkers of metabolism and inflammation (BM). Univariable analysis to evaluate the association of farm collected data and blood assessed variables with metritis cure were performed, and variables with P ≤ 0.20 were offered to multivariable logistic regression models and retained if P ≤ 0.15. The area under the curve (AUC) for models predicting SC using farm data only and farm + BM, was 0.70 and 0.76 respectively. Cell blood count variables were not retained in the models for SC. For models predicting cure among CEF cows, the AUC was 0.75, 0.77, 0.80, and 0.80 for models using farm data only, farm + CBC, farm + BM, and farm + CBC + BM, respectively. Predictive models of metritis cure had fair accuracy, with SC models being less accurate than models predictive of cure among CEF cows. Additionally, adding BM variables marginally improved the accuracy of models using farm collected data, while CBC data did not improve the accuracy of predictive models.

Application of behavior data to predictive exploratory models of metritis self-cure and treatment failure in dairy cows

The objective was to evaluate the performance of exploratory models containing routinely available on-farm data, behavior data, and the combination of both to predict metritis self-cure (SC) and treatment failure (TF). Holstein cows (n = 1,061) were fitted with a collar-mounted automated- health monitoring device (AHMD) from -21 ± 3 to 60 ± 3 d relative to calving to monitor rumination and activity. Cows were examined for diagnosis of metritis at 4 ± 1, 7 ± 1, and 9 ± 1 DIM. Cows diagnosed with metritis (n = 132), characterized by watery, fetid, reddish/brownish vaginal discharge (VD) were randomly allocated to one of 2 treatments: Control (CON; n = 62) - no treatment at the time of metritis diagnosis (d 0); Ceftiofur (CEF; n = 70) - subcutaneous injection of 6.6 mg/kg of ceftiofur crystalline-free acid on d 0 and 3 relative to diagnosis. Cure was determined 12 d after diagnosis and was considered when VD became mucoid and not fetid. Cows in CON were used to determine SC and cows in CEF were used to determine TF. Univariable analyses were performed using farm-collected data (parity, calving season, calving-related disorders, body condition score, rectal temperature, and days in milk at metritis diagnosis) and behavior data (i.e., daily averages of rumination, activity generated by AHMD, and derived variables) to assess their association with metritis SC or TF. Variables with a P ≤ 0.20 were included in the multivariable logistic regression exploratory models. To predict SC, the area under the curve (AUC) for the exploratory model containing only data routinely available on-farm was 0.75. The final exploratory model to predict SC combining routinely available on-farm data and behavior data increased the AUC to 0.87, sensitivity (Se) 87% and specificity (Sp) 71%. To predict TF, the AUC for the exploratory model containing only data routinely available on-farm was 0.90. The final exploratory model combining routinely available on-farm data and behavior data increased the AUC to 0.93, Se of 93% and Sp of 82%. Cross-validation analysis revealed that generalizability of the exploratory models was poor, which indicates that the findings are applicable to the conditions of the present exploratory study. In summary, the addition of behavior data contributed to increasing the prediction of SC and TF. Developing and validating accurate prediction models for SC could lead to a reduction in antimicrobial use, whereas accurate prediction of cows that would have TF may allow for better management decisions.

Changes in Uterine Metabolome Associated with Metritis Development and Cure in Lactating Holstein Cows

The objective of this study was to identify alterations in the vaginal discharge (VD) metabolome and potential biomarkers to predict metritis development and a cure in dairy cows. This prospective cohort study was conducted on two dairies located in CA and TX. Vaginal discharge was evaluated and collected using the Metricheck® device. Cows were examined for metritis at 4, 7, and 9 days in milk (DIM). Cows with a fetid, watery, and reddish-brown uterine discharge were classified as having metritis and randomized to receive ceftiofur (n = 10) or remain untreated (n = 7). A cure was defined as the absence of a fetid, watery, reddish-brown uterine discharge at 14 d after enrollment. Vaginal discharge samples were collected from 86 cows within 6 h after parturition, at 4 and 7 DIM, at metritis diagnosis, and at 4 and 7 days after metritis diagnosis. Cows with metritis (MET; n = 17) were paired with counterparts without metritis (HTH) of a similar DIM and parity (n = 34). The uterine metabolome was evaluated using untargeted gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). Metabolomic data were analyzed using the MetaboAnalyst 5.0. Data were log-transformed and auto-scaled for normalization. Univariate analyses, including the fold-change, were performed to identify the metabolites linked to metritis development and its cure and principal component analysis and partial least squares discriminant analysis were performed to explain metabolite variance between animals developing or not developing metritis and being cured or not being cured of metritis. Comparing HTH with MET cows at calving, 12 metabolites were upregulated, and one was downregulated. At four and seven DIM, 51 and 74 metabolites, respectively, were altered between MET and HTH cows. After metritis development, three and five metabolites were upregulated in cows that were cured and in cows that received treatment and were cured, respectively. In all scenarios, the metabolites lignoceric, malic, and maleic acids, ornithine, and hypotaurine, which are associated with arginine/aminoacyl-tRNA biosynthesis and taurine/purine metabolism, were upregulated in HTH cows. Metritis was associated with changes in the uterine metabolome. Cows not being cured of metritis had changes in the uterus metabolome independent of receiving ceftiofur or remaining untreated. Metabolome analysis may be an important tool to understand the vaginal discharge changes during postpartum and the dynamics of metritis development and cures and help to identify biomarkers to predict metritis being cured.

Acute and 28-Day Repeated-Dose Oral Toxicity of the Herbal Formula Guixiong Yimu San in Mice and Sprague-Dawley Rats

To evaluate the acute and chronic 28-day repeated-dose oral toxicity of Guixiong Yimu San (GYS) in mice and rats, high-performance liquid chromatography (HPLC) was used to determine the stachydrine hydrochloride in GYS as the quality control. In the acute toxicity trial, the mice were administered orally at a dose rate of 30.0 g GYS/kg body weight (BW) three times a day. The general behavior, side effects, and death rate were noticed for 14 days following treatment. In the subacute toxicity trial, the rats were administered orally at a dose rates of30.0, 15.0, and 7.5 g GYS/kg BW once a day for 28 days. The rats were monitored every day for clinical signs and deaths; changes in body weight and relative organ weights (ROW) were recorded every week, hematological, biochemical, and pathological parameters were also examined at the end of treatment. The results showed that the level of stachydrine hydrochloride in GYS was 2.272 mg/g. In the acute toxicity trial, the maximum-tolerated dose of GYS was more than 90.0 g/kg BW, and no adverse effects or mortalities were noticed during the 14 days in the mice. At the given dose, there were no death or toxicity signs all through the 28-day subacute toxicity trial.The oral administration of GYS at a dose rate of 30.0 g/kg/day BW had no substantial effects on BW, ROW, blood hematology, gross pathology, histopathology, and biochemistry (except glucose), so 30.0 g/kg BW/day was determined as the no-observed-adverse-effect dosage.

Association of time to metritis diagnosis with circulating concentration of metabolites, minerals, and haptoglobin in Jersey cows

Our objective was to investigate the association of early metritis [EMET, diagnosed at <5 d in milk (DIM)] and late metritis (LMET, diagnosed at ≥5 DIM) with circulating concentrations of energy metabolites, minerals, and haptoglobin (Hp) throughout the first 14 d postpartum. A total of 379 purebred Jersey cows were enrolled in a prospective cohort study from a single herd in west Texas. Cows were examined for metritis using the Metricheck device (Simcro Ltd.) at 4, 7, and 10 DIM. Cows identified by farm employees as possible metritis cases were also evaluated for metritis. Blood samples were collected for analysis of concentrations of Ca, Mg, and glucose at DIM 1 through 5, 7, 10, and 14. Albumin, urea, fructosamine, free fatty acids (FFA), creatinine, and β-hydroxybutyrate (BHB) were analyzed at DIM 3, 5, 7, 10, and 14, and Hp at DIM 1 through 5 and 7. Data were analyzed using the MIXED and PHREG procedures of SAS (SAS Institute Inc.). A series of mixed general linear models accounting for repeated measures were fitted to the data. The independent variables metritis [no metritis (NMET), EMET, and LMET], DIM of analyte assessment, and parity were forced in all models. Multivariable Cox proportional hazard models were built to assess the risk of pregnancy and culling within 150 DIM. The overall metritis incidence was 26.9% (EMET = 49; LMET = 53; NMET = 277). Average concentrations of glucose, Mg, and urea were not associated with metritis. The associations of Ca, creatinine, BHB, and fructosamine with metritis were dependent on the DIM of analyte assessment. Cows categorized as EMET and LMET had, on average, lower albumin and fructosamine compared with NMET cows. Both EMET and LMET cows had, on average, greater BHB than NMET cows. A greater FFA concentration was only observed in cows diagnosed with EMET compared with NMET cows (EMET = 0.58, LMET = 0.52, NMET = 0.48 mmol/L). Additionally, circulating Hp concentration was greater for LMET and EMET compared with NMET cows, and EMET cows had greater Hp compared with LMET cows (EMET = 1.15; LMET = 1.00; NMET = 0.84). In conclusion, several blood biomarkers were temporally associated with early versus late metritis diagnosis in postpartum Jersey cows. No meaningful differences were observed in production, reproduction, or culling between EMET and LMET cows. These results suggest that cows with EMET undergo a more severe degree of inflammation and negative energy balance compared with NMET cows.

Relationship of peripartum inflammation with reproductive health in dairy cows

Failure of a robust but well-regulated immune response may result in reproductive tract inflammatory disease, such as metritis, purulent vaginal discharge, or endometritis. Metritis is consistently associated with reduced diversity of the uterine microbiome. Similarly, purulent vaginal discharge at 4 to 6 wk postpartum is strongly associated with bacterial infection of the uterus. Conversely, the microbiome of healthy cows and those with subclinical endometritis is generally similar, so endometritis is thought to be a consequence of dysregulation of inflammation rather than changes in uterine microbiota. There is an emerging concept that inflammation is not only a reaction to injury or disease but that it can be a consequence of or precursor to metabolic disturbances. The degree of systemic inflammation is associated with the level of trauma and bacterial contamination of the uterus or mammary gland, the degree of fat mobilization and release of nonesterified fatty acids, and perhaps leaky gut, all of which result in the release of proinflammatory cytokines. Therefore, uterine inflammation may be exacerbated by systemic inflammation, but may also contribute to heightened systemic inflammation in transition cows. However, clarity and progress are limited by a lack of validated criteria to quantify systemic inflammation and to identify its sources.

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.

Cytological endometritis diagnosis in primiparous versus multiparous dairy cows

Endometritis is a uterine disease of dairy cows causing substantial negative effects on reproductive performance and inflicting considerable economic losses. It is typically diagnosed by endometrial cytology evaluation and commonly named cytological endometritis (CEM). In most previous studies, cows were defined as CEM positive if the proportion of polymorphonuclear cells (%PMN) in their endometrial cytology was above a pre-set threshold. Thresholds were established based on CEM diagnosis in association with reproductive performance, typically analyzed by a single reproductive parameter and calculated for all cows together. Our objective was to examine whether primiparous and multiparous cows should optimally be diagnosed for CEM by different %PMN thresholds and sampling timings, using a combination of several reproductive performance parameters. Two endometrial cytobrush cytology samples were collected from Holstein-Friesian dairy cows (n = 415; 269 multiparous; 146 primiparous), at 30-40 d in milk (DIM) and 60-70 DIM, and %PMN were evaluated microscopically (blindly; Diff-Quick stain, Medi-Market). The %PMN thresholds were set at ≥1% to ≥10%, ≥15%, and ≥20%, and accordingly, for each of the thresholds, several reproductive performance parameters were compared between CEM-positive versus CEM-negative cows. Upon application of several analytic approaches, our results indicated that optimal CEM diagnosis should be performed by different criteria in primiparous and multiparous cows: in primiparous cows at 30-40 DIM, using a threshold of ≥7%PMN, and in multiparous cows at 60-70 DIM, using a threshold of ≥4%PMN. Such a diagnostic approach provides a comprehensive view of the reproductive prognosis of CEM-positive primiparous and multiparous cows, which is pertinent information for researchers, veterinarians, and farmers.

Integration of statistical inferences and machine learning algorithms for prediction of metritis cure in dairy cows

The study's objectives were to identify cow-level and environmental factors associated with metritis cure to predict metritis cure using traditional statistics and machine learning algorithms. The data set used was from a previous study comparing the efficacy of different therapies and self-cure for metritis. Metritis was defined as fetid, watery, reddish-brownish discharge, with or without fever. Cure was defined as an absence of metritis signs 12 d after diagnosis. Cows were randomly allocated to receive a subcutaneous injection of 6.6 mg/kg of ceftiofur crystalline-free acid (Excede, Zoetis) at the day of diagnosis and 3 d later (n = 275); and no treatment at the time of metritis diagnosis (n = 275). The variables days in milk (DIM) at metritis diagnosis, treatment, season of the metritis diagnosis, month of metritis diagnostic, number of lactation, parity, calving score, dystocia, retained fetal membranes, body condition score at d 5 postpartum, vulvovaginal laceration score, the rectal temperature at the metritis diagnosis, fever at diagnosis, milk production from the day before to metritis diagnosis, and milk production slope up to 5, 7, and 9 DIM were offered to univariate logistic regression. Variables included in the multivariable logistic regression model were selected from the univariate analysis according to P-value. Variables were offered to the model to assess the association between these factors and metritis cure. Additionally, the univariate logistic regression variables were offered to a recursive feature elimination to find the optimal subset of features for a machine learning algorithms analysis. Cows without vulvovaginal laceration had 1.91 higher odds of curing of metritis than cows with vulvovaginal laceration. Cows that developed metritis at >7 DIM had 2.09 higher odds of being cured than cows that developed metritis at ≤7 DIM. For rectal temperature, each degree Celsius above 39.4°C led to lower odds to be cured than cows with rectal temperature ≤39.4°C. Furthermore, milk production slope and milk production difference from the day before to the metritis diagnosis were essential variables to predict metritis cure. Cows that had reduced milk production from the day before to the metritis diagnosis had lower odds to be cured than cows with moderate milk production increase. The results from the multivariable logistic regression and receiver operating characteristic analysis indicated that cows developing metritis at >7 DIM, with increase in milk production, and with a rectal temperature ≤39.40°C had increased likelihood of cure of metritis with an accuracy of 75%. The machine learning analysis showed that in addition to these variables, calving-related disorders, season, and month of metritis event were needed to predict whether the cow will cure or not from metritis with an accuracy ≥70% and F1 score (harmonic mean between precision and recall) ≥0.78. Although machine learning algorithms are acknowledged as powerful tools for predictive classification, the current study was unable to replicate its potential benefits. More research is needed to optimize predictive models of metritis cure.

Predictive models to identify Holstein cows at risk of metritis and clinical cure and reproductive/productive failure following antimicrobial treatment

Precision dairy farming, specifically the design of management strategies according to the animal's needs, may soon become the norm since automated technologies that generate large amounts of data for each individual are becoming more affordable. Our objectives were to determine whether the use of behavioral changes could improve the accuracy of prediction of the risk of metritis and the risk of clinical cure of cows diagnosed with metritis. Addition of behavioral data to the algorithms to predict the outcomes of interest increased their accuracy by 7 to 32%. The incidence of metritis in postpartum dairy cows ranges from 20 to 40%. Unfortunately, approximately 30% of cows treated with antimicrobials following the diagnosis of metritis fail to cure and have impaired reproductive performance. Automated behavior monitoring devices have become more affordable and accessible. In the current study, we investigated whether behavioral changes recorded by automated devices improve models for the prediction, within 42 h of calving, of metritis and acute metritis. Furthermore, we determined whether behavioral changes aid on the prediction, 24 h before the diagnosis of metritis, of cure in response to antimicrobial treatments and the reproductive (failure to become pregnant)/productive (bottom quartile of milk yield) success within 200 d in milk (DIM). At enrollment, Holstein cows (n = 555) from two farms were fitted with an automated device (HR-LDn tag, SCR Engineers Ltd., Netanya, Israel) 21 d before the expected calving date. Cows were examined for metritis (fetid, watery, red/brown uterine discharge) and were randomly assigned to receive ampicillin trihydrate or ceftiofur crystalline free acid treatments. Contemporary cows with no clinical diseases (NoCD = 362) were paired with cows with metritis. Cure from metritis was defined as the absence of fetid, watery, pink/brown uterine discharge and rectal temperature < 39.5 °C, 11 d after diagnosis. In addition, cows in the lowest quartile of milk production, within lactation and farm, and that were not pregnant by 200 DIM were classified as failure. We built models containing: routinely-available data [lactation number (1, 2, ≥3), calf sex, still birth, twining, dystocia, vaginal laceration score, days on the close-up diets], body condition score (BCS) and BCS change from enrollment to calving (ΔBCS), behavior (feeding, rumination, idle, and active time), and their interactions. The area under the curve (AUC) of the models containing routinely-available data, ΔBCS, and behavior data at 2 DIM to predict metritis [AUC = 0.82, 95% confidence interval (CI) = 0.78, 0.85] and acute metritis (AUC = 0.87, 95% CI = 0.83, 0.89) were (P < 0.01) excellent; whereas the models predicting cure (AUC = 0.92, 95% CI = 0.85, 0.95) and failure (AUC = 0.90, 95% CI = 0.84, 0.94) were outstanding. Behavioral changes peripartum contribute for the identification of cows at risk for metritis, allowing the development of preventive strategies. In addition, predicting whether cows will respond to antimicrobial treatment and succeed during lactation may allow for earlier decision-making regarding treatment and culling.

Prolonged, low-grade inflammation in the first week of lactation: Associations with mineral, protein, and energy balance markers, and milk yield, in a clinically healthy Jersey cow cohort

Our objectives were to perform a proof-of-concept study to assess the association of a prolonged inflammatory state (based on a continually elevated haptoglobin concentration at the end of the first week after parturition) with mineral, protein, and energy balance markers in the first 2 wk after parturition, and milk production in the first 60 d of lactation in clinically healthy cows. We conducted a cohort study in 1 herd in west Texas that was milking Jersey and Jersey-Holstein crosses. Only multiparous Jersey cows were eligible for enrollment. Cows were classified as having or not having elevated haptoglobin concentrations based on plasma concentrations evaluated on d 4 and 7 postpartum. We used median concentrations of haptoglobin in the reference population (i.e., before the exclusion of cows diagnosed with clinical diseases) as the limits for categorizing cows into 2 groups: cows with plasma haptoglobin concentrations greater than the median values on both d 4 (0.49 g/L) and 7 (0.35 g/L) had continually elevated haptoglobin (with eHp); and cows with plasma haptoglobin concentrations lower than or equal to the median values of the reference population on d 4 or 7 did not have continually elevated haptoglobin (without eHp). Next, cows with clinical diseases in the first 2 wk of the postpartum period were excluded, so that 233 cows remained for the final analyses. Evaluated outcomes were average daily milk production across the first 60 d of lactation, plasma Ca, Mg, and glucose concentrations on d 1, 2, 3, 4, 5, 7, 10, and 14 postpartum, and β-hydroxybutyrate (BHB), nonesterified fatty acids (NEFA), fructosamine, albumin, urea, and creatinine concentrations on d 3, 5, 7, 10, and 14 postpartum. Rectal temperatures measured on d 4, 7, and 10 postpartum were also analyzed. We performed statistical analyses using linear mixed models while accounting for the repeated effect of sampling time (plasma analytes and rectal temperature models) and weekly milk test (milk production model). Cows with eHp had lower plasma Ca concentrations in the first 2 wk after calving, but no differences in Mg, BHB, NEFA, glucose, or rectal temperatures compared to cows without eHp. Cows with eHp had lower plasma fructosamine, albumin, and urea concentrations in a time-dependent manner. They also had lower milk production (2.3 kg/d less than cows without eHp in the first 60 DIM). Our study demonstrated that 25% of cows without clinical disorders in the first 2 wk after parturition had continually elevated haptoglobin concentrations at d 7 after parturition relative to d 4, suggestive of a prolonged, low-grade systemic inflammatory state. More observational studies are needed to more fully characterize the duration of prolonged postpartum subclinical inflammation in cows without clinical diseases, as well as its long-term effects, and to evaluate the use of other potential markers of systemic inflammation to describe this disorder.

Metritis in dairy cows is preceded by alterations in biochemical profile prepartum and at parturition

Metritis in dairy cows is classified as a puerperal disease that affects all layers of the uterine epithelium and occurs during the first 21 days after parturition. The objectives of this study were to identify potential predictive biomarkers of metritis, to monitor the biochemical profile of pre-metritic dairy cows, and to evaluate the reproductive performance of dairy cows with metritis. Fifty-five cows without metritis and fifteen cows that showed clinical signs of metritis were enrolled in this study. Blood samples were collected at -21, -14 and - 7 days before calving and at parturition and assayed for urea, creatinine, aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), total cholesterol, fibrinogen, total calcium, β-hydroxybutyrate (BHB) and non-esterified fatty acids (NEFA) concentrations. Serum fibrinogen on 21, 14 and 7 days prepartum and at parturition was the strongest discriminator between metritic and control cows. Moreover, metritic cows had lower (P < 0.05) concentrations of urea, creatinine, cholesterol and calcium and higher (P < 0.05) serum AST, GGT activities, and serum fibrinogen, BHB and NEFA concentrations when compared to control cows. The number of days to first ovulation, insemination, services per pregnancy and days to pregnancy were greater (P < 0.05) for metritic cows than the control group, and the follicle size was smaller (P < 0.05) for metritic cows than the control group. Our results indicate alterations in the biochemical profile of dairy cows with metritis and the negative impact on the reproductive performance of metritic cows raised in tropical conditions. In addition, this study showed that the serum fibrinogen could be used as screening biomarkers to indicate cows that might have metritis during the postpartum period.

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.