Diagnosis of acute puerperal metritis by electronic nose device analysis of vaginal discharge in dairy cows

Metrisor: A novel diagnostic method for metritis detection in cattle based on machine learning and sensors

The Metrisor device has been developed using gas sensors for rapid, highly accurate and effective diagnosis of metritis. 513 cattle uteri were collected from abattoirs and swabs were taken for microbiological testing. The Metrisor device was used to measure intrauterine gases. The results showed a bacterial growth rate of 75.75 % in uteri with clinical metritis. In uteri positive for clinical metritis, the most commonly isolated and identified bacteria were Trueperella pyogenes, Fusobacterium necrophorum and Escherichia coli. Measurements taken with Metrisor to determine the presence of metritis in the uterus yielded the most successful results in evaluations of relevant machine learning algorithms. The ICO (Iterative Classifier Optimizer) algorithm achieved 71.22 % accuracy, 64.40 % precision and 71.20 % recall. Experiments were conducted to examine bacterial growth in the uterus and the random forest algorithm produced the most successful results with accuracy, precision and recall values of 78.16 %, 75.30 % and 78.20 % respectively. ICO also showed high performance in experiments to determine bacterial growth in metritis-positive uteri, with accuracy, precision and recall values of 78.97 %, 77.20 % and 79.00 %, respectively. In conclusion, the Metrisor device demonstrated high accuracy in detecting metritis and bacterial growth in uteri and could identify bacteria such as E. coli, S. aureus, coagulase-negative staphylococci, T. pyogenes, Bacillus spp., Clostridium spp. and F. necrophorum with rates up to 80 %. It provides a reliable, rapid and effective means of detecting metritis in animals in the field without the need for laboratory facilities.

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

Our objective was to assess the association of cow-related factors with metritis cure risk and economically important outcomes. In this prospective cohort study nested inside a randomized clinical trial, cows enrolled in a clinical trial that aimed to evaluate an alternative metritis therapy that had available plasma samples collected at metritis diagnosis were included. Metritis was defined as fetid, watery, reddish-brownish discharge with or without fever, and cure was defined as the absence of metritis signs 12 d after diagnosis. Cows were randomly allocated to remain untreated (CON; n = 147) or receive subcutaneous injections of 6.6 mg/kg of ceftiofur crystalline-free acid at enrollment and 72 h later (CEF, n = 168). Additionally, a random subset of 150 nonmetritic cows (NMET) was also included to compare milk production, reproductive performance, and culling responses. Cow-related factors evaluated include plasma concentrations of nonesterified fatty acids, β-hydroxybutyrate, and haptoglobin (Hp), parity, rectal temperature, and days in milk (DIM) at metritis diagnosis, vulvovaginal laceration (VL), BCS, dystocia, twins, and retained placenta. Among CON cows, DIM at metritis diagnosis was positively associated with metritis cure [threshold = 8, area under the curve (AUC) = 0.67], whereas plasma Hp concentration tended to be negatively associated with cure of metritis (threshold = 0.54 mg/mL, AUC = 0.64). Among CEF cows, DIM at metritis diagnosis (threshold = 5, AUC = 0.67) and dystocia were positively associated with metritis cure, whereas VL and Hp (threshold = 0.78 mg/mL, AUC = 0.76) were negatively associated with cure. For CON cows that were diagnosed with metritis after 8 DIM or had plasma Hp concentration ≤0.54 mg/mL, milk production, pregnancy, and culling risk were comparable to NMET cows. However, performance was impaired when cows that developed metritis at ≤8 DIM or had Hp >0.54 mg/mL were left untreated. Among CEF cows, Hp, DIM at metritis diagnosis, dystocia, and VL were associated with metritis cure. Milk yield, reproductive performance, and culling losses are more pronounced among CEF cows when metritis was diagnosed at ≤5 DIM, Hp >0.78 mg/mL, or if they had VL or dystocia. In conclusion, these data indicate that timing of the onset of metritis and inflammatory biomarkers could be used for the development of a selective therapy strategy for metritis, but more research is needed to identify more accurate predictors of metritis spontaneous cure and treatment failure.

Welfare Quality® for dairy cows: towards a sensor-based assessment

This Research Reflection addresses the possibilities for Welfare Quality® to evolve from an assessment method based on data gathered on punctual visits to the farm to an assessment method based on sensor data. This approach could provide continuous and objective data, while being less costly and time consuming. Precision Livestock Farming (PLF) technologies enabling the monitorisation of Welfare Quality® measures are reviewed and discussed. For those measures that cannot be assessed by current technologies, some options to be developed are proposed. Picturing future dairy farms, the need for multipurpose and non-invasive PLF technologies is stated, in order to avoid an excessive artificialisation of the production system. Social concerns regarding digitalisation are also discussed.

Biomarkers of fitness and welfare in dairy cattle: healthy productivity

Milk production intensification has led to several unwanted aspects, such as sustainability issues and environmental pollution. Among these, increased milk outputs that have been achieved over the last 70 years have led to several health and pathophysiological conditions in high yielding dairy animals, including metabolic diseases that were uncommon in the past. Increased occurrence of diverse metabolic diseases in cattle and other domestic animals is a key feature of domestication that not only affects the animals' health and productivity, but also may have important and adverse health impacts on human consumers through the elevated use of drugs and antibiotics. These aspects will influence economical and ethical aspects in the near future. Therefore, finding and establishing proper biomarkers for early detection of metabolic diseases is of great interest. In the present review, recent work on the discovery of fitness, stress and welfare biomarkers in dairy cows is presented, focusing in particular on possible biomarkers of energy balance and oxidative stress in plasma and milk, and biomarkers of production-related diseases and decreased fertility.

Adaptive immunity in the postpartum uterus: Potential use of vaccines to control metritis

After parturition, dairy cows rely on an effective innate immune response, through the actions of neutrophils, macrophages, and antimicrobial peptides, to clear the uterus from pathogenic bacteria, such as E. coli, Bacteroides spp, F. necrophorum and T. pyogenes. However, the role of adaptive immunity in the postpartum uterus is less understood. In this review, we explore concepts of mucosal adaptive immunity and discuss recent findings regarding the efficacy of vaccines to reduce metritis in dairy cows. Areas of lymphocytic aggregates are seen throughout the bovine reproductive tract after parturition, but it is unknown if their development is influenced by previous exposure to pathogens or other intrinsic factors. Through the actions of Treg cells and γδ T cells, the uterus is an immune-tolerant environment during pregnancy. After parturition, the dynamics in the endometrial and circulating lymphocytic populations differ among cows that develop uterine diseases and healthy counterparts. However, the functionality of those cells has not yet been determined. It has been hypothesized that cows that fail to switch their uterine environment from an anti-inflammatory state prior to parturition to a pro-inflammatory state after calving are more susceptible to uterine infections. Given the nature of metritis related pathogens and the importance of innate immunity to uterine defense mechanisms, we speculate that an adaptive immunity biased towards a Th1/Th17 cellular response will provide best protection against uterine infections. Few studies have evaluated the efficacy of immunization in reducing the incidence of metritis in dairy cows revealing inconsistent findings.

Electronic Nose Technology Fails to Sniff Out Acute Mountain Sickness

Berendsen, Remco R., Marieke E. van Vessem, Marcel Bruins, Luc J.S.M. Teppema, Leon P.H.J. Aarts, and Bengt Kayser. Electronic nose technology fails to sniff out acute mountain sickness. High Alt Med Biol. 19:232-236, 2018.

AIM

The aim of the study was to evaluate whether an electronic nose can discriminate between individuals with and without acute mountain sickness (AMS) following rapid ascent to 4554 m.

RESULTS

We recruited recreational climbers (19 women, 82 men; age 35 ± 10 years, mean ± standard deviation [SD]) upon arrival at 4554 m (Capanna Regina Margherita, Italy) for a proof of concept study. AMS was assessed with the Lake Louise self-report score (LLSRS) and the abbreviated Environmental Symptoms Questionnaire (ESQc); scores ≥3 and ≥0.7 were considered AMS, respectively. Exhaled air was analyzed with an electronic nose (Aeonose; The eNose Company, Netherlands). The collected data were analyzed using an artificial neural network. AMS prevalence was 44% with the LLSRS (mean score of those sick 4.4 ± 1.4 [SD]) and 20% with the ESQc (1.2 ± 0.5). The electronic nose could not discriminate between AMS and no AMS (LLSRS p = 0.291; ESQc p = 0.805).

CONCLUSION

The electronic nose technology utilized in this study could not discriminate between climbers with and without symptoms of AMS in the setting of an acute exposure to an altitude of 4554 m. At this stage, we cannot fully exclude that this technology per se is not able to discriminate for AMS. The quest for objective means to diagnose AMS thus continues.

Molecular aspects of uterine diseases in dogs

Uterine diseases are common in dogs, particularly in countries where elective spaying is not usually performed. The associated clinical illnesses may be of varying degree ranging from merely decreased fertility to a critical pyometra requiring intensive care to survive. The diagnosis of some uterine diseases is generally uncomplicated, such as in a classic pyometra presenting with enlarged, fluid-filled uterus, purulent vaginal discharge and characteristic signs of illness or in other disorders associated with uterine enlargement. However, it can be more puzzling in diseases with normal uterine size and very mild or obscure clinical signs. It is important to recognize the uterine diseases early because of the risk of potentially life-threatening complications such as sepsis developing if treatment is delayed in cases where bacterial infection is present. In breeding bitches, an early diagnosis, that is when the disease has not developed extensively, will increase the possibility of non-surgical treatment options without increased risk and thereby also increasing chances of maintained fertility. Early diagnosis and treatment initiation are thus favourable for complete recovery, also in less severe uterine diseases and those without infection. Molecular markers are molecules in biological samples that can be measured for diagnostic purposes, outcome prediction, and for gaining more information about different physiological and pathological conditions. Examples of commonly evaluated markers include laboratory variables analysed in blood, urine, cytological or tissue biopsy samples. Regarding the genetic pre-disposition for different uterine diseases in dogs, information is lacking. Recently, the global gene expression in uterine tissue in dogs has been investigated more closely, and newly developed technologies provide excellent opportunities for identifying molecular markers worth exploring further. The focus of this review article is to highlight findings on markers relevant for diagnosis, prediction of prognosis and treatment outcome in the most common uterine diseases in dogs.

Electronic Nose Feature Extraction Methods: A Review

Many research groups in academia and industry are focusing on the performance improvement of electronic nose (E-nose) systems mainly involving three optimizations, which are sensitive material selection and sensor array optimization, enhanced feature extraction methods and pattern recognition method selection. For a specific application, the feature extraction method is a basic part of these three optimizations and a key point in E-nose system performance improvement. The aim of a feature extraction method is to extract robust information from the sensor response with less redundancy to ensure the effectiveness of the subsequent pattern recognition algorithm. Many kinds of feature extraction methods have been used in E-nose applications, such as extraction from the original response curves, curve fitting parameters, transform domains, phase space (PS) and dynamic moments (DM), parallel factor analysis (PARAFAC), energy vector (EV), power density spectrum (PSD), window time slicing (WTS) and moving window time slicing (MWTS), moving window function capture (MWFC), etc. The object of this review is to provide a summary of the various feature extraction methods used in E-noses in recent years, as well as to give some suggestions and new inspiration to propose more effective feature extraction methods for the development of E-nose technology.

A Novel Feature Extraction Approach Using Window Function Capturing and QPSO-SVM for Enhancing Electronic Nose Performance

In this paper, a novel feature extraction approach which can be referred to as moving window function capturing (MWFC) has been proposed to analyze signals of an electronic nose (E-nose) used for detecting types of infectious pathogens in rat wounds. Meanwhile, a quantum-behaved particle swarm optimization (QPSO) algorithm is implemented in conjunction with support vector machine (SVM) for realizing a synchronization optimization of the sensor array and SVM model parameters. The results prove the efficacy of the proposed method for E-nose feature extraction, which can lead to a higher classification accuracy rate compared to other established techniques. Meanwhile it is interesting to note that different classification results can be obtained by changing the types, widths or positions of windows. By selecting the optimum window function for the sensor response, the performance of an E-nose can be enhanced.

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.