Course and severity of postpartum metritis cases following antibiotic and PGF2α administration in postpartum metritis cows infected with BoHV-4

Protective effect of Timosaponin AIII on Escherichia coli-induced endometritis in mice through inhibiting inflammatory response and regulating uterine microbiota structure

Endometritis is a sort of general reproductive disease, which can lead to infertility in both humans and animals. Escherichia coli (E. coli) is recognised as the main bacterial etiology of endometritis among livestock and causes huge economic losses to dairy farming industry. Antibiotics are frequently used in the clinical treatment of endometritis; nevertheless, long-term use may result in adverse effects, including bacterial resistance and food safety concerns. TSAIII, one of the active pharmacological components of A. asphodeloides, has exhibited multiple biological activities, including anticancer, anti-angiogenesis, and anti-inflammatory properties. However, the protective effects of TSAIII in E. coli-challenged endometritis remain unclear. This study aimed to clarify the role of TSAIII in E. coli-induced endometritis in mice and elucidate its specific molecular mechanisms. In the present research, TSAIII treatment markedly alleviated the E. coli-induced uterine histopathological injury, and decreased myeloperoxidase (MPO) activity and pro-inflammatory cytokines levels in uterine tissue. Our results further demonstrated that TSAIII improved uterine epithelial barrier function by restoring the expressions of tight junction proteins. Furthermore, TSAIII administration noticeably suppressed the activation of the TLR4/NF-κB pathway and the NLRP3 inflammasome. Importantly, we found that TSAIII could regulate the uterine microbiota structure and composition in E. coli-induced mouse endometritis. In conclusion, these data demonstrate that treatment with TSAIII protects against E. coli-induced endometritis via modulating uterine microbiota composition, inhibiting TLR4/NF-κB pathway and NLRP3 inflammasome activation, in addition to improving uterine epithelial barrier function. Therefore, the results of this study provide a new therapeutic to potentially prevent endometritis.

The curative effect of ozonated bidistilled water on Escherichia coli-induced endometritis in rats

BACKGROUND

Endometritis is a prevalent and challenging condition that affects livestock, and its effective treatment is the use of intrauterine antibiotics. Antibiotic use may lead to negative consequences, including residue in tissues and the emergence of antibiotic resistance.

OBJECTIVES

The aim of this study was to assess the therapeutic potential of ozonated bidistilled water in the treatment of Escherichia coli-induced endometritis in rat models, comparing it to conventional antibiotic treatment.

METHODS

A total of 21 female Wistar Albino rats were used for this study. E. coli from the uterus of cows with endometritis at a concentration of 1.0 × 109 cfu/mL inoculated into rat uteruses. After inoculation, it was confirmed macroscopically that experimental endometritis was induced in all individuals. And, the rats with endometritis were randomly divided into three groups treated with intrauterine bidistilled water enriched with ozone, antibiotics and 0.9% NaCl. The uterine tissues were examined histopathologically.

RESULTS

In the semiquantitative analyses, significantly lower histopathological scores were observed for both the bidistilled water enriched with ozone and antibiotic-treated endometritis groups compared to the control group (p < 0.05).

CONCLUSIONS

Ozone-enriched bidistilled water can be used in the treatment of experimentally induced endometritis in rats, and can provide effective microbiological and histopathological improvement. Further studies involving larger populations of different species are needed to determine the medical suitability of this new treatment.

Incidence and Treatments of Bovine Mastitis and Other Diseases on 37 Dairy Farms in Wisconsin

The aim of this research was to describe the incidence and treatments of mastitis and other common bovine diseases using one year of retrospective observational data (n = 50,329 cow-lactations) obtained from herd management software of 37 large dairy farms in Wisconsin. Incidence rate (IR) was defined as the number of first cases of each disease divided by the number of lactations per farm. Clinical mastitis (CM) remains the most diagnosed disease of dairy cows. Across all herds, the mean IR (cases per 100 cow-lactations) was 24.4 for clinical mastitis, 14.5 for foot disorders (FD), 11.2 for metritis (ME), 8.6 for ketosis (KE), 7.4 for retained fetal membranes (RFM), 4.5 for diarrhea (DI), 3.1 for displaced abomasum (DA), 2.9 for pneumonia (PN) and 1.9 for milk fever (MF). More than 30% of cows that had first cases of CM, DA, RFM, DI, and FD did not receive antibiotics. Of those treated, more than 50% of cows diagnosed with PN, ME and CM received ceftiofur as a treatment. The IR of mastitis and most other diseases was greater in older cows (parity ≥ 3) during the first 100 days of lactation and these cows were more likely to receive antibiotic treatments (as compared to younger cows diagnosed in later lactation). Cows of first and second parities in early lactation were more likely to remain in the herd after diagnosis of disease, as compared to older cows and cows in later stages of lactation. Most older cows diagnosed with CM in later lactation were culled before completion of the lactation. These results provide baseline data for disease incidence in dairy cows on modern U.S. dairy farms and reinforce the role of mastitis as an important cause of dairy cow morbidity.

Phenotypic and Genotypic Characterization of C. perfringens Isolates from Dairy Cows with a Pathological Puerperium

Clostridium perfringens (C. perfringens) forms part of the intestinal microbiome, but is also a known pathogen in histotoxic infections. The significance of the pathogen as a cause of uterine infections in cattle has been little studied so far. Here, we analyzed the association between a pathological puerperium in cattle and the detection of C. perfringens in a prospective longitudinal study. Clostridium perfringens were only found in vaginal and uterine samples of diseased cattle, and were absent in healthy controls. Isolates (n = 21) were tested for the production of major toxins (alpha-, beta-, epsilon-toxin) by ELISA and for the potential of production of major (alpha-, beta-, iota-toxin) and minor toxins (beta2 toxin) by PCR. Furthermore, antimicrobial susceptibility was also tested phenotypically by microdilution. Despite the frequent use of tetracycline treatment in cows suffering from puerperal disorders, no isolate showed phenotypic tetracycline resistance. Most isolates did not release major amounts of toxin. The strict association of C. perfringens with puerperal disease, together with the absence of major toxins might hint towards a major role of other or unknown clostridial virulence factors in uterine disease.

A review of the resistome within the digestive tract of livestock

Antimicrobials have been widely used to prevent and treat infectious diseases and promote growth in food-production animals. However, the occurrence of antimicrobial resistance poses a huge threat to public and animal health, especially in less developed countries where food-producing animals often intermingle with humans. To limit the spread of antimicrobial resistance from food-production animals to humans and the environment, it is essential to have a comprehensive knowledge of the role of the resistome in antimicrobial resistance (AMR), The resistome refers to the collection of all antimicrobial resistance genes associated with microbiota in a given environment. The dense microbiota in the digestive tract is known to harbour one of the most diverse resistomes in nature. Studies of the resistome in the digestive tract of humans and animals are increasing exponentially as a result of advancements in next-generation sequencing and the expansion of bioinformatic resources/tools to identify and describe the resistome. In this review, we outline the various tools/bioinformatic pipelines currently available to characterize and understand the nature of the intestinal resistome of swine, poultry, and ruminants. We then propose future research directions including analysis of resistome using long-read sequencing, investigation in the role of mobile genetic elements in the expression, function and transmission of AMR. This review outlines the current knowledge and approaches to studying the resistome in food-producing animals and sheds light on future strategies to reduce antimicrobial usage and control the spread of AMR both within and from livestock production systems.

Epidemiology of antimicrobial resistance (AMR) on California dairies: descriptive and cluster analyses of AMR phenotype of fecal commensal bacteria isolated from adult cows

Background

This study describes the occurrence of antimicrobial resistance (AMR) in commensal Escherichia coli and Enterococcus/Streptococcus spp. (ES) isolated from fecal samples of dairy cows and assesses the variation of AMR profiles across regions and seasons following the implementation of the Food and Agricultural Code (FAC) Sections 14400–14408 (formerly known as Senate Bill, SB 27) in California (CA).

Methods

The study was conducted on ten dairies distributed across CA’s three milk sheds: Northern California (NCA), Northern San Joaquin Valley (NSJV), and the Greater Southern California (GSCA). On each study dairy, individual fecal samples were collected from two cohorts of lactating dairy cows during the fall/winter 2018 and spring/summer 2019 seasons. Each cohort comprised of 12 cows per dairy. The fecal samples were collected at enrollment before calving (close-up stage) and then monthly thereafter for four consecutive time points up to 120 days in milk. A total of 2,171 E. coli and 2,158 ES isolates were tested for antimicrobial susceptibility using the broth microdilution method against a select panel of antimicrobials.

Results

The E. coli isolates showed high resistance to florfenicol (83.31% ± 0.80) and sulphadimethoxine (32.45%), while resistance to ampicillin (1.10% ± 0.21), ceftiofur (1.93% ± 0.29), danofloxacin (4.01% ± 0.42), enrofloxacin (3.31% ± 0.38), gentamicin (0.32% ± 0.12) and neomycin (1.61% ± 0.27) had low resistance proportions. The ES isolates were highly resistant to tildipirosin (50.18% ± 1.10), tilmicosin (48% ± 1.10), tiamulin (42%) and florfenicol (46% ± 1.10), but were minimally resistant to ampicillin (0.23%) and penicillin (0.20%). Multidrug resistance (MDR) (resistance to at least 1 drug in ≥3 antimicrobial classes) was observed in 14.14% of E. coli isolates and 39% of ES isolates. Escherichia coli isolates recovered during winter showed higher MDR prevalence compared to summer isolates (20.33% vs. 8.04%). A higher prevalence of MDR was observed in NSJV (17.29%) and GSCA (15.34%) compared with NCA (10.10%).

Conclusions

Our findings showed high rates of AMR to several drugs that are not labeled for use in lactating dairy cattle 20 months of age or older. Conversely, very low resistance was observed for drugs labeled for use in adult dairy cows, such as cephalosporins and penicillin. Overall, our findings identified important differences in AMR by antimicrobial class, region and season.

Analysis of puerperal metritis treatment records in a grazing dairy farm in Argentina

OBJECTIVE

To assess the efficacy of antibiotic usage for the treatment of puerperal metritis (PM) and its association with reproductive performance, a retrospective cohort study including a total of 9168 records of cows from a dairy farm in Argentina was run.

MATERIAL AND METHODS

Cows having a PM3 (metricheck, scale 0-3) and treated with ceftiofur (ceftiofur crystalline free acid, 6.6 mg/kg) at 0-21 days postpartum (p. p.) (n = 2688), and cows having a PM 1-2 and not treated with an antibiotic at 0-21 days p. p. (n = 6480) were included in the study. All cows were reexamined with metricheck to assess the clinical cure (vaginal discharge [VD] score 0), partial cure (VD score similar or lower than previous), no cure (VD score higher than previous). Cows with a metricheck VD1-3 after 0-21 days p. p. were diagnosed as clinical endometritis (CE) 1-3. The occurrence of PM1-3, cure rate, calving to conception interval, the hazard of pregnancy, odds for non-pregnancy, and odds for CE were analyzed using SAS software.

RESULTS

A total of 8876 PM1-3 records were included, 2435 records of PM3 treatments with ceftiofur (27.43 %), and 6441 records of PM1-2 (72.57 %) with no treatment. Cows having PM1 and PM2 became pregnant 14 and 12 days earlier than cows with PM3 (p < 0.001). The PM3 ceftiofur treated cows had a clinical cure of 24.85 % (PM0); 53.63 % had a partially cure; and 18.52 % no cure. Conversely, cows with PM1-2 had a 51.96 %, 20.70 %, and 24.53 % cure rate, respectively (p < 0.001). Cows having complete cure became pregnant 13 and 11 days earlier than cows having partial cure and no cure (p < 0.001). Cows that had PM3 during the first 21 days p. p. had twice the chances of developing CE compared to cows having PM1-2 (41.28 % vs. 24.14 %, p < 0.001). After 21 days p. p., less than 1 % of cows with clinical cure developed CE compared to 63.32 % that developed CE with partial cure, and 38.21 % with no cure (p < 0.001).

CONCLUSION AND CLINICAL RELEVANCE

After ceftiofur treatment, 78 % of cows were cured when measured by disappearance of fetid VD but only 25 % of cows had clinical cure when measured by appearance of a clear VD. The cows that remained with clinical metritis had more chances of having CE after 21 days p. p. and had more days open than cows with clear normal VD.

An assessment of bovine herpes virus 4 as a causative agent in abortions and neonatal death

Numerous viruses, including bovine viral diarrhoea virus (BVDV), bovine herpes virus 1 (BoHV-1) and bovine herpes virus 4 (BoHV-4), and other pathogens are the most common causes of reproductive disorders and are responsible for huge economic losses in livestock production. This study investigates the aetiological role of BoHV-4 in fertility problems such as abortions, stillbirth and birth with unviable calves. Retrospective samples from 38 animals, including 17 aborting cows, 17 aborted foetuses, three stillborn calves and one unviable newborn calf were analysed. The BoHV-4 genome was detected in 25 (65.7%) animals by polymerase chain reaction. In 14 of these infected animals, we detected co-infection with BVDV, while the co-presence of BoHV-1 was also detected in one animal. In addition to the high prevalence of BoHV-4 genome in materials related to fertility problems, isolation of BoHV-4 from the brain of one stillborn calf indicated a causal link between BoHV-4 and fertility problems, such as abortion, stillbirths or birth with unviable calves.

Antibiotic treatment of metritis in dairy cows-A meta-analysis

The objective of this meta-analysis was to assess the efficacy of the treatment of bovine metritis with common antibiotic and nonantibiotic treatment options. Acute puerperal metritis, a systemic and potentially painful illness with rectal temperature >39.5°C and signs of toxemia due to an infection of the uterus, occurs within 21 d after parturition. Because of the infectious nature, antibiotics are considered beneficial for the treatment of acute puerperal metritis. Each use of an antimicrobial drug, however, is associated with selective pressure for eventual emergence of resistant bacteria. The 23 trials evaluated in the course of a previously conducted systematic review were the basis for meta-analytic investigations. Selected trials were screened regarding their eligibility for the following investigations: (1) comparison of different antibiotic treatments with respect to metritis prevalence at time of re-examination, (2) efficacy of ceftiofur treatment with respect to metritis prevalence at time of re-examination, (3) comparison of efficacy of antibiotic versus nonantibiotic drugs with respect to metritis prevalence at time of re-examination, and (4) equivalence assessment of treatment effects on reproductive performance measures. Where at least 3 trials had investigated the same outcome variable and met the inclusion criteria (inclusion of a control or reference group diagnosed with metritis; reporting means and standard deviation in case of continuous data), meta-analytic investigations were carried out. Due to a shortage of comparable studies, we could not conduct investigations (1) and (3). Ceftiofur treatment of 828 metritic cows was associated with a decrease in the prevalence of metritis following treatment in comparison to 804 untreated cows. In conclusion, meta-analytic investigations uncovered a need for more high-quality studies. Furthermore, a positive effect of the most commonly used antibiotic drug, ceftiofur, for the treatment of bovine metritis could be shown. A comparison with other antibiotic or nonantibiotic treatment options could not be made.

Uterine infection with bovine herpesvirus type 4 in dairy cows

Diseases of the reproductive tract are a frequent problem in dairy herds. Herpesviruses are uterine pathogens also involved in other clinical diseases; for example, bovine herpesvirus type 4 BoHV-4 induces abortion, enteritis, metritis, pneumonia and vaginitis, but it can also be detected in healthy cows. The role of BoHV-4 in the development of clinical endometritis (CE) or subclinical endometritis (SE) has not clearly been described. Therefore, the objective of this study was to describe the prevalence of uterine BoHV-4 infection and its relationship with clinical, bacteriological and cytological findings in dairy cows 20-30 days after calving. The experiment was performed as a completely randomized block design, with farm (n = 10) as blocking criterion and with cow (n = 397) as the experimental unit. Logistic regression models were used to assess the effect of BoHV-4 infection on CE, SE and reproductive performance. Proportion of cows infected with BoHV-4 was 5.8% (n = 23/397). BoHV-4 was isolated in 11.0% (n = 12/109), 4.8% (n = 4/84) and 3.6% (n = 7/194) of cows diagnosed as CE, SE or healthy, respectively. A logistic model revealed that BoHV-4 infection showed a tendency to increase the risk for CE (AOR = 2.17; p = .10) but significantly reduced both, the odds for artificial insemination within 80 days post-partum (dpp) (AOR = 0.37; p = .035) and for pregnancy within 200 dpp (AOR = 0.13; p = .004). Furthermore, BoHV-4 infection increased the chance for intrauterine infection with Trueperella pyogenes (AOR = 5.55; p < .001) and vice versa (AOR = 5.79, p < .001). In conclusion, BoHV-4 infection is associated with reduced chances for insemination and pregnancy by 200 dpp and showed a trend to be associated with increased risk for CE. Furthermore, BoHV-4 and Trueperella pyogenes infections are strongly related.

Laboratory Findings Suggesting an Association Between BoHV-4 and Bovine Abortions in Southern Belgium

Abortions cause heavy economic losses for the bovine sector. The use of a standardized panel of analyses covering a large spectrum of pathogens responsible of abortion in cattle allowed demonstrating the direct involvement of at least one pathogen in 57% of analysed abortions in the southern part of Belgium. This result suggests a margin of improvement in the diagnostic efficacy. In order to evaluate the interest to broaden the list of pathogens included in the panel of analyses, the implication of bovine herpesvirus 4 (BoHV-4) in abortion was assessed by two different studies. In the first study, coupled serology was performed after abortion on 714 dams to identify specific seroconversion against BoHV-4. The overall seroconversion in cows was 19.5%, with a higher frequency in primiparous compared to multiparous females. In addition, the type of breed (beef cattle) and the time period from the fourth quarter 2008 until the last quarter 2009 were significantly related to the seroconversion of cows. The second study investigated the virus ability to infect the foetus. In this study, 368 cases of bovine abortions were specifically tested for BoHV-4, using PCR on foetus tissues and ELISA on dam and foetus sera. The results showed a maternal seroprevalence of 64.7%, a foetal seroprevalence of 0.8% and a PCR prevalence in foetuses of 1.1%, demonstrating the ability of BoHV-4 to infect the foetus.

Evidence for the use of ceftiofur for treatment of metritis in dairy cattle

Metritis is a cause of postparturient uterine disease in dairy cattle and is most commonly associated with watery fetid red-brown uterine discharge occurring in the first 21 days postpartum. The most severe form of metritis (puerperal metritis) often warrants antibiotic therapy. This article analyzes the current literature to determine the efficacy of ceftiofur in the treatment of metritis. Evidence-based review of the current literature suggests that there is evidence for the use of ceftiofur in the treatment of metritis. However, review of the literature also reveals the need for more studies with negative control groups.

Invited review: Antibiotic treatment of metritis in dairy cows: a systematic approach

Acute puerperal metritis (APM) is an acute systemic illness with fever ≥ 39.5 °C and signs of toxemia due to an infection of the uterus occurring within 21 d after parturition. Because of the infectious nature of APM, antibiotics are considered beneficial for its treatment. Each use of an antimicrobial drug, however, is associated with selective pressure for the emergence of resistant bacteria. Hence, there is a significant need to encourage prudent use of antibiotics and alternative therapies to antibiotics. Therefore, the objective of this study was to systematically review the current literature on treatment of APM. A comprehensive and systematic literature search was conducted utilizing the PubMed and CAB Abstracts databases to identify literature focusing on the antibiotic therapy of puerperal metritis in the cow. After application of specific exclusion criteria, 21 publications comprising 23 trials remained for final evaluation. Data extraction revealed that the majority of the studies (n = 19) were attributable to the highest evidence level. Of 21 studies controlled, 11 had an untreated group and 3 a positive control group. The majority of the studies (n = 17) applied ceftiofur for the treatment of APM. Concerning the efficacy of ceftiofur, 7 studies observed clinical improvement, whereas none found improved reproductive performance. Fewer than half of the studies (n = 10) performed a bacteriological examination and only 4 implemented an antibiotic susceptibility test. Also, 3 studies (13.0%) described a self-cure rate per se. Little attention was given to the issue of bacterial resistance (n = 3), the need for reducing the application of antibiotics (n = 2), or guidelines for prudent use of antibiotics (n = 1). Our findings demonstrate that implementation of bacteriological examinations, sensitivity testing, and determination of minimum inhibitory concentrations, as well as reporting and discussion of critical issues (e.g., self-cure rates, resistance, prudent drug use), were suboptimal. On the other hand, the quality of studies on the treatment of APM was good, as indicated by evidence level 1. Nevertheless, more high-quality research considering self-cure rates is necessary to address critical issues related to APM and crucial to the dairy industry, such as resistance, prudent use of antibiotics, animal welfare, and cost-benefit ratios.

Impact of Bovine Herpesvirus 4 (BoHV-4) on Reproduction

Bovine herpesvirus 4 (BoHV-4) is increasingly considered as responsible for various reproductive troubles. This virus infects blood mononuclear cells and displays a specific tropism for vascular endothelia, mammary tissue, endometrium and foetal tissues. Viral multiplication can be reactivated by corticosteroids or stress, both factors present at calving. BoHV-4 has been isolated in a large variety of clinical cases, primarily metritis, vaginitis and mastitis, but also endometritis, abortion and orchitis. Its impact on reproductive performance has been suggested by several epidemiological studies: seroprevalence against BoHV-4 is higher in aborted females and in repeat breeders. Nevertheless, its intrinsic pathogenic power seems low, symptoms developing only when BoHV-4 cooperates with bacteria: within the uterus or mammary gland. BoHV-4 is rather currently considered as a cofactor for the development of an inflammatory reaction initiated by bacteria.