Mastitis In Cows Research Articles

Comparative Profiling of Milk Somatic Cells Proteomes Revealed Key Players in Mammary Immune Mechanisms During Mastitis in Tropical Sahiwal (Bos indicus) Cows.

Bovine mastitis poses a significant economic burden on the dairy industry worldwide. This pioneering proteomic study conducted a comparative profiling of milk somatic cell (SC) proteins contributing to mammary immune defense during subclinical and clinical mastitis (CM) in Sahiwal (Bos indicus) cows. Based on California mastitis test (CMT) scores, milk SC counts, differential leukocyte counts (DLCs), and bacteriological culture results, quarter milk SC samples were categorized into healthy (H), subclinical mastitis (SCM), and CM groups. Comparative proteome profiling of milk SCs was done using a label-free liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) proteomic approach. The identified upregulated proteins in mastitis groups such as Vanin 2, Thioredoxin reductase-like selenoprotein T, Ceramidase, Lymphocyte antigen 75, Misshapen-like kinase 1 (MINK1), Thrombospondin 1, Macrophage scavenger receptor 1, Leupaxin, and Lipoamide acyltransferase, involved in immune responses. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed immune functions and pathways like antigen processing, complement cascades, extracellular matrix receptor interaction, efferocytosis, leukocyte migration, chemokine, peroxisome proliferator-activated receptors (PPARs), and transforming growth factor (TGF)-beta signaling. These findings provide essential information on proteomic profiling in milk SCs and contribute valuable insights into immune-related proteins regulated during mastitis in dairy cows. Further, validated proteins (Vanin 2, MINK1, and Thrombospondin 1) offer potential inflammatory biomarkers for early mastitis detection in dairy cows.

Extracellular vesicle miRNome during subclinical mastitis in dairy cows

Bovine mastitis is one of the main inflammatory diseases that can affect the udder during lactation. Somatic cell counts and sometimes microbiological tests are routinely adopted during monitoring diagnostics in dairy herds. However, subclinical mastitis is challenging to identify, reducing the possibility of early treatments. The main aim of this study was to investigate the miRNome profile of extracellular vesicles isolated from milk as potential biomarkers of subclinical mastitis. Milk samples were collected from a total of 60 dairy cows during routine monitoring tests. Small RNA sequencing technology was applied to extracellular vesicles of milk samples collected from cows classified according to the somatic cell count to identify differences in the miRNome between mastitic and healthy cows. A total of 1997 miRNAs were differentially expressed between both groups. Among them, 68 miRNAs whose FDRs were < 0.05 were mostly downregulated, with only one upregulated miRNA (i.e., miR-361). Functional analysis revealed that miR-455-3p, miR-503-3p, miR-1301-3p and miR-361-5p are involved in the regulation of several biological processes related to mastitis, including immune system-related processes. This study suggests the involvement of extracellular vesicle-derived miRNAs in the regulation of mastitis. Moreover, these findings provide evidence that miRNAs from milk extracellular vesicles can be used to identify biomarkers of mastitis. However, further studies must be conducted to validate these miRNAs, especially for subclinical diagnosis.

Маститы – проблема безопасности, качества и сыропригодности молока сырого

Bovine mastitis is a common hygiene-related issue in milk production. It increases the somatic cell count in milk. Somatic cell count is an important indirect indicator of milk quality. Somatic cells include those of udder and blood. Normally, one healthy udder lobe secretes ≤ 500,000 somatic cells per 1 cm3 milk. In the presence of pathogenic bacteria, the same amount indicates a latent infection. Inflammatory processes in the udder include impaired secretion and mastitis. They increase the number of leukocytes and other blood cells in the total somatic cell count, which means that the milk came from sick cows. Raw milk for cheese production must contain ≤ 4×105 cells per 1 cm3. Mastitis, or garget milk is not suitable for cheese production. Staphylococcus aureus is the most common causative agent of staphylococcal mastitis in cows. Coagulase-positive staphylococci are responsible for 30-50% cases of infectious mastitis. They pose great risks for bulk-formed cheeses. Mastitis affects milk processing, taste, and storage capacity. It is high in chlorides and low in lactose, which gives it a flat and salty-bitter taste. If somatic cell count exceeds 5×105 cells per 1 cm3, the resulting milk has poor thermal stability. As the content of somatic cells in milk increases, so does the rennet coagulation time: fat goes into whey and moisture in curd increases, which eventually reduces cheese yield.

Streptococcus dysgalactiae Septic Arthritis of a Pre-Weaned Holstein Bull Calf - a Case Report

Septic arthritis is a joint inflammation caused by an infectious agent. Septic arthritis takes a long time to heal, and as such it may have a significant economic impact. A one-month-old Friesian Holstein calf was lame and had swelling in the left carpal joint. Synovial fluid samples from the left carpal joint were used for bacterial identification, which use API Strept 20 (bioMérieux, Inc – USA). The identification results showed that septic arthritis was caused by Streptococcus dysgalactiae subspecies dysgalactiae,. Streptococcus dysgalactiae subspecies dysgalactiae play a significant role even though it plays a major role in mastitis in dairy cows.

Effect of Exogenous Melatonin on Performance and Mastitis in Dairy Cows.

Mastitis is an important factor affecting the health of cows that leads to elevated somatic cell counts in milk, which can seriously affect milk quality and result in huge economic losses for the livestock industry. Therefore, the aim of this trial was to investigate the effect of melatonin on performance and mastitis in dairy cows. Forty-eight Holstein cows with a similar body weight (470 ± 10 kg), parity (2.75 ± 1.23), number of lactation days (143 ± 43 days), BCS (3.0-3.5), milk yield (36.80 ± 4.18 kg), and somatic cell count (300,000-500,000 cells/mL) were selected and randomly divided into four groups: control (CON group), trial Ⅰ (T80 group), trial Ⅱ (T120 group), and trial Ⅲ (T160 group). Twelve cows in trial groups I, II, and III were pre-dispensed 80, 120, and 160 mg of melatonin in edible glutinous rice capsules along with the basal ration, respectively, while the control group was fed an empty glutinous rice capsule along with the ration. The trial period was 37 days, which included a 7-day adaptive phase followed by a 30-day experimental period. At the end of the trial period, feeding was ended and the cows were observed for 7 days. Milk samples were collected on days 0, 7, 14, 21, 28, and 37 to determine the somatic cell number and milk composition. Blood samples were collected on days 0, 15, 30, and 37 of the trial to determine the serum biochemical indicators, antioxidant and immune indicators, and the amount of melatonin in the blood. The results showed that the somatic cell counts of lactating cows in the CON group were lower than those in the T120 group on days 14 (p < 0.05) and 28 (p < 0.01) at 1 week after melatonin cessation. The milk protein percentage and milk fat percentage of cows in the T120 group were higher than those in the CON group (p < 0.01). The total protein and globulin content in the T120 group were higher than those in the CON group (p < 0.01). In terms of antioxidant capacity and immunity, the cows 1 week after melatonin cessation showed higher superoxide dismutase activity and interleukin-10 contents (p < 0.01) compared with the CON group and lower malondialdehyde and tumor necrosis factor-alpha contents (p < 0.01) compared with the T120 group. The melatonin content in the T120 group was increased relative to that in the other groups. In conclusion, exogenous melatonin can increase the content of milk components, reduce the somatic cell count, and improve the antioxidant capacity and immune responses to a certain extent. Under the experimental conditions, 120 mg/day melatonin is recommended for mid- to late-lactation cows.

514 Roles of core regulatory noncoding RNAs in bovine Staphylococcus aureus subclinical mastitis

Abstract Staphylococcus aureus (S. aureus) is an opportunistic pathogen frequently associated with subclinical mastitis and accounts for a large proportion of the economic losses due to mastitis on Canadian dairy farms. Despite a plethora of investigations on the molecular mechanisms of mastitis, little information is available on the roles of regulatory noncoding RNAs (ncRNA). This study aimed to uncover the regulatory roles of microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) in the response to subclinical mastitis due to S. aureus of cows. Transcriptome sequencing (RNA-Seq and miRNA-Seq) was conducted on milk somatic cells from 13 cows with S. aureus subclinical mastitis [high somatic cell counts (SCC) of ≥350,000 cells/mL for ≥3 consecutive months and positive for S. aureus only], and 5 healthy cows (low SCC&amp;lt; 100,000 cells/mL for ≥3 consecutive months and negative for mastitis pathogens). RNASeq and smRNASeq nf-core bioinformatics pipelines were used to process the data. Results showed that 97 miRNAs (36 up-regulated and 61 down-regulated) and 1,565 lncRNAs (617 up-regulated and 948 down-regulated) were differentially expressed (DE; FDR&amp;lt; 0.05) between S. aureus subclinical mastitic cows and healthy controls. Competing endogenous networks comprising co-expressed differentially expressed mRNAs (DEGs), miRNAs (DEMs), and lncRNAs (DELs) were constructed. CytoHubba, a Cytoscape plugin, was utilized to identify the top hub regulatory ncRNAs including bta-miR-2387, bta-miR-331, bta-miR-95, bta-miR-744, bta-miR-455, bta-novel-miR-60, bta-miR-3533, bta-miR-500, bta-miR-1249 and bta-novel-miR-66). The results revealed that the main hubs (downregulated bta-miR-2387 and upregulated bta-miR-331) potentially regulate numerous DEGs during S. aureus subclinical mastitis such as NFKB1, IL10RA, IL17RA, TLR10, LOC112442665, LOC112448481 and LOC112442015, etc., and TUNAR, LOC112445429, LOC112444484 and LOC101907369, respectively. Functional analysis of bta-miR-331 target genes revealed roles in several KEGG pathways (e.g., tight junction, bacterial invasion of epithelial cells) and biological processes gene ontology (GO) terms (e.g., cell adhesion, cell locomotion and cell motility). Similarly, roles for bta-miR-2387 in KEGG pathways like JAK-STAT signaling pathway, NOD-like receptor signaling pathway and inflammatory bowel disease, and biological process GO terms such as inflammatory response, neutrophil migration, leucocyte migration and response to cytokine were revealed. MiR-331 has been found to promote cell proliferation, migration, and invasion of breast cancer. Furthermore, bta-miR-2387 has been shown to regulate several immune pathways which aid in improving the movement of spermatids across the epithelium and preleptotene spermatocytes across the blood-testis barrier during spermatogenesis. This supports our findings and suggests that bta-miR-2387 and bta-miR-331 could be pivotal regulators of immune-related genes and pathways during S. aureus subclinical mastitis. Thus, they hold potential as biomarkers for the development of therapeutic and diagnostic tools for managing subclinical mastitis.

Antimicrobial Resistance and Use on Chinese Dairy Farms: Awareness and Opinions Regarding Selective Treatments of Farm Managers.

In China's expanding dairy industry, a lack of oversight regarding antimicrobial use and increasing antimicrobial resistance are evident. Selective treatments of dairy cows for clinical mastitis or dry cow therapy are proposed to promote judicious antimicrobial use without adversely impacting cattle health. These approaches have been successfully implemented on farms in other countries. On 28 October 2023, a 2-day in-person seminar was held in Beijing, China, on selective antimicrobial treatments of dairy cows for clinical mastitis or dry cow therapy on large Chinese dairy farms. Concurrently, a qualitative study involving 15 technical managers from the 13 largest Chinese dairy groups used focus group discussions and questionnaires to explore perspectives on selective treatments of dairy cows for clinical mastitis or dry cow therapy. The main outcomes assessed were opinions and concerns regarding implementing selective antimicrobial treatments. Although there was diversity of cognition on AMR and selective treatments, the technical managers were generally positive regarding adoption of selective treatments. However, they expressed a need for more evidence and tools, including anticipated economic impacts, effects of delaying treatment until diagnosis, accurate interpretation of milk recording data, safe use of internal teat sealants, and spread of pathogens. Participants stressed the need for awareness, staff training, farm management, and China-specific standards, suggesting large-scale trials to assess efficacy of selective treatments. The findings revealed key challenges and barriers currently impeding selective AMU practices. These insights could inform efforts to promote judicious AMU on farms through targeted treatment regimens, reducing mounting selective pressure driving resistance.

Inflammatory Signaling via PEIZO1 Engages and Enhances the LPS-Mediated Apoptosis during Clinical Mastitis.

Bovine clinical mastitis is characterized by inflammation and immune responses, with apoptosis of mammary epithelial cells as a cellular reaction to infection. PIEZO1, identified as a mechanotransduction effector channel in nonruminant animals and sensitive to both mechanical stimuli or inflammatory signals like lipopolysaccharide (LPS). However, its role in inflammatory processes in cattle has not been well-documented. The aim of this study was to elucidate the in situ expression of PIEZO1 in bovine mammary gland and its potential involvement in clinical mastitis. We observed widespread distribution and upregulation of PIEZO1 in mammary epithelial cells in clinical mastitis cows and LPS-induced mouse models, indicating a conserved role across species. In vitro studies using mammary epithelial cells (MAC-T) revealed that LPS upregulates PIEZO1. Notably, the effects of PIEZO1 artificial activator Yoda1 increased apoptosis and NLRP3 expression, effects mitigated by PIEZO1 silencing or NLRP3 inhibition. In conclusion, the activation of the PIEZO1-NLRP3 pathway induces abnormal apoptosis in mammary epithelial cells, potentially serving as a regulatory mechanism to combat inflammatory responses to abnormal stimuli.

Mastitis has a cumulative and lasting effect on milk yield and lactose content in dairy cows

Milk lactose content (LC) physiologically decreases with parity order in dairy cows, but also after udder health inflammation(s) and/or in presence of elevated milk SCC in subclinical cases. Therefore, the progressive decrease in milk LC observed along cows' productive life can be attributed to a combination of factors that altogether impair the epithelial integrity, resulting in weaker tight junctions, e.g., physiological aging of epithelium, mechanical epithelial stress due to milking, and experienced clinical or subclinical mastitis. Mastitis is known to affect the udder synthesis ability too, so our intention through this study was to evaluate if there is a cumulative and lasting effect of mammary gland inflammation(s) on milk yield (MY) and LC. For this purpose, we used diagnoses of clinical mastitis and milk data of Austrian Fleckvieh cows to evaluate the effect of cumulative mastitis events on LC and MY. Only mastitis diagnoses recorded by trained veterinarians were used. Finally, we investigated if cumulative mastitis is a heritable trait and whether it is genetically correlated with either LC or MY. Estimates were obtained using univariate and bivariate linear animal models. A significant reduction in LC and MY was observed in cows that suffered from mastitis compared with those that did not experience udder inflammation. The h2 of cumulative mastitis is promising and much greater (0.09) than the h2 of the binary event itself (≤0.03). The genetic correlations between cumulative mastitis with LC and MY were negative, suggesting that cows with a great genetic merit for MY and LC are expected to be more resistant to repeated inflammations and less recidivist. When we used number of lifetime SCC peaks (≥200,000 or 400,000 cells/mL) to calculate cumulative inflammation events, h2 was even higher (up to 0.38), implying that also subclinical mastitis has a relevant negative impact on both LC and MY. Finally, the present study demonstrated how repeated mastitis events can permanently affect the mammary gland epithelial integrity and synthesis ability, and that the number of cumulative mastitis is a promising phenotype to be used in selection index in combination with other indicator traits toward more resistant and resilient mammary glands.

Syndecan-3 inhibits LPS-induced Inflammation of Bovine Mammary Epithelial Cells through the NF-κB Signal Transduction Pathway

In mastitis, excessive inflammation caused by lipopolysaccharide (LPS) is an important factor leading to mammary tissue damage. Therefore, exploring the regulatory factors that can inhibit the widespread inflammation caused by LPS is crucial. Syndecan-3 (SDC3) has been found to play an active role in anti-inflammatory infection by inhibiting leukocyte adhesion, reducing the accumulation of inflammatory products, such as reactive oxygen species, and competing with chemokines; however, the role and regulatory mechanism of SDC3 in mastitis remains unknown. Therefore, this study aimed to reveal the effect of SDC3 on LPS-induced inflammation in bovine mammary epithelial cells (BMECs) and explore its possible molecular mechanisms. First, we constructed a BMEC inflammatory model. It was found that cells stimulated with 10 μg/mL LPS for 24 h strongly induced the expression of inflammatory cytokines and had no toxic effect on cells, which was the best condition to simulate the BMECs inflammatory response in vitro. Subsequently, we used overexpression and RNAi interference, Real Time Quantitative PCR (RT-qPCR), and Western blot assays to explore the effects of SDC3 on LPS-induced inflammatory factors and their mechanisms. The results showed that overexpression of SDC3 could inhibit the transcriptional levels of inflammatory cytokines IL-6, IL-1β, and TNFα induced by LPS and inhibit the activation of the NF-κB inflammatory pathway by inhibiting the expression of NF-κB p50 and p-IκBα and promoting the expression of IκBα. Our results suggest that SDC3 inhibits the LPS-induced inflammatory response of BMECs through the NF-κB pathway, in which NF-κB p50 may be an important target of SDC3. These findings lay the foundation for elucidating the molecular regulatory mechanisms of dairy cow mastitis.

Determination of antibacterial and anti-biofilm activities of Terpinen-4-ol loaded polydopamine nanoparticles against Staphylococcus aureus isolates from cows with subclinical mastitis.

Mastitis in cows is one of the most important diseases that give rise to economic losses in dairy farms. Increasing antimicrobial resistance in Staphylococcus aureus, one of the most common causes of mastitis, is a significant health problem. Due to the problems encountered in treating infections caused by resistant strains, developing alternative treatment methods, such as Nanomaterial systems and natural agents, are important. The essential oil of Melaleuca alternifolia is used as an antibacterial and the primary active component is terpinen-4-ol. This study aimed to investigate the antibacterial and anti-biofilm activity of terpinen-4-ol and terpinen-4-ol loaded polydopamine (T-PDA) nanoparticles against S. aureus isolates, which were resistant to at least one group of antibiotics isolated from milk samples of subclinical mastitis cows. The S. aureus strains were identified by biochemical tests and verified with the API Staph kit. The antibiotic susceptibility of the isolates was determined by the disc diffusion method. The broth microdilution method determined the antimicrobial activities of the terpinen-4-ol and T-PDA nanoparticles, and anti-biofilm activities were assessed using the modified crystal violet method. All of the isolates were resistant to benzylpenicillin and susceptible to trimethoprim/sulfamethoxazole. Multi-antibiotic resistance was detected in the 11 S. aureus isolates used in this study. For the terpinen-4-ol and T-PDA nanoparticles, MIC values were determined in the range of 0.125-0.5% (µL/mL) and 0.125-0.25% (µL/mL), respectively. None of the isolates formed biofilms. As a result, it was found that the antibacterial efficacy of the T- PDA nanoparticles was higher against nine of the S. aureus isolates than against the terpinen-4-ol.

Detection of Listeria monocytogenes in cheese and in cow mastitis – a case report

Listeria monocytogenes is ubiquitous and causes listeriosis, which manifests in animals in the form of septicaemia, encephalitis, abortions, and, rarely, mastitis. In humans, food is the main source of infection, which is the reason food business operators take samples and test for Listeria. We report a case of L. monocytogenesdetection in traditional cheese made from raw milk, and subsequent investigation revealed that L. monocytogenes was excreted from a cow mammary gland. Although treatment was carried out according to the results of the antibiogram, there was no improvement in the subclinical mastitis and the excretion of L. monocytogenes after treatment was 8.8x102cfu/mL, and therefore the cow was removed from the herd.

Precision Agriculture: MXene-Based 3D Biosensors for Early Detection of Subclinical Mastitis in Dairy Cows

INTRODUCTION Mastitis, inflammation of mammary glands, is caused by pathogens like Streptococcus and Staphylococci, posing an economic challenge in the US dairy industry. Subclinical mastitis (SCM), asymptomatic and hard to detect, leads to prolonged milk yield declines. SCM costs the US over $2 billion annually. Current tests include somatic cell count, California Test, and Wisconsin Mastitis Test, but they offer periodic, qualitative measurements with moderate sensitivities (less than 90%) and specificities (85%). Consequently, there is a pressing need for reliable, early, continuous, and on-site detection of SCM to enhance milk yield, control the spread of infection, and health management, and improve the well-being of dairy cows.Herein, we developed a 3D-printed MXene sensor for the detection of mastitis, providing a high sensitivity and a ≤1 min response time. This tool can aid US livestock farmers in dairy herd management. SENSOR FABRICATION Device manufacturing comprises three steps. First, the CAD design of the sensor (Figure 2) guides printing using a 25 μm resolution extrusion-based 3D printer. A UV-curable epoxy resin forms the sensor base, with unique microstructures enhancing surface area (Figure 3). The sensor geometry incorporates a ~280 μm periodic lateral pattern for increased surface area and a 3D geometric diffusion interface. Uncontrollably, a random microfold pattern emerges due to the epoxy resin's photo-sensitivity. These microstructures, acting as microelectrodes, amplify the sensor's surface area, boosting analytical sensitivity.Next, a 100nm gold layer is applied to the sensor base using an e-beam evaporator with a shadow mask. Sensing materials are then drop-casted onto each electrode. The NAGase sensing electrode is coated with Ti3C2 nanosheets (MXene) decorated with anti-NAGase. The pH sensing electrode modified with poly(3-octyl-thiophene) and is covered by a hydrogen ion-selective membrane (H-ISM). The reference electrode (RE) is constructed by applying Ag/AgCl paste onto grooves around each working electrode (Figure 2). RESULTS AND DISCUSSION First, surface morphologies and electrochemical characterizations were conducted. FE-SEM images depict the lateral pattern and micro-folds of the sensor base (Figure 3). EDS and mapping analyses confirm uniform MXene distribution on the gold surface. Moreover, cyclic voltammetry (CV) explores electrode electrochemical behavior in different media. CV of MXene with ferro/ferricyanide shows distinctive peaks for mediator oxidation and reduction. CV without a mediator reveals characteristic MXene oxidation peaks, highlighting the sensor's mediator-free capability for direct applications in dairy farms without need for mediator solution.For pH sensing, open circuit potentiometry (OCP) was used. Figure 4 shows OCP response rising with increasing pH values. The calibration graph in Figure 4 establishes a linear correlation between pH values and OCP, aligning with the Nernstian equation for ion-selective electrodes. The pH sensor successfully measures milk sample pH, demonstrating remarkable selectivity in the complex milk matrix.The NAGase biosensor employs two sensing modalities for laboratory and field applications. Electrochemical impedance spectroscopy with a mediator generates Nyquist plots for calculating charge transfer resistance (Rct) in the presence of NAGase. Figure 5 displays a calibration graph with a linear correlation between Rct and the logarithmic concentration of NAGase. The NAGase-anti-NAGase interaction forms immunocomplexes on the MXene surface, increasing resistance to the mediator's redox reaction. This feature serves as the sensing mechanism for NAGase, a potential biomarker in mastitis.Due to MXene's self-oxidation tendency without a mediator, CV technique used as a mediator-free alternative for practical field applications. In Figure 6, voltammograms show decreasing oxidative and reductive currents with increasing NAGase concentration. Oxidative peak currents used as the signal, exhibiting a negative correlation with NAGase concentration. The immunocomplexes formation acts as an insulative shield, impeding redox reactions. This innovative sensor aims to reduce time and effort in detecting mastitis in dairy cows, controlling pathogen spread. Figure 1

Characterization and antioxidant activity of nano-formulated berberine and cyperus rotundus extracts with anti-inflammatory effects in mastitis-induced rats

Bovine mastitis caused by infectious pathogens, mainly Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), constitutes a major destructive challenge for the dairy industry and public health. Berberine chloride (BER) and Cyperus rotundus possess a broad spectrum of anti-inflammatory, antioxidant, antibacterial, and antiproliferative activities; however, their bioavailability is low. This research aimed first to prepare an ethanolic extract of Cyperus rotundus rhizomes (CRE) followed by screening its phytochemical contents, then synthesis of BER and CRE loaded chitosan nanoparticles (NPs) (BER/CH-NPs and CRE/CH-NPs), afterward, the analysis of their loading efficiency in addition to the morphological and physicochemical characterization of the formulated NPs employing Scanning Electron Microscopy (SEM), Zeta Potential (ZP), Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD) assessments compared to their crude forms to evaluate the enhancement of bioavailability and stability. Isolation of bacterial strains from the milk of mastitic cows, used for induction of mammary gland (MG) inflammation in female albino rats, and a preliminary investigation of the prophylactic oral doses of the prepared NPs against S. aureus-induced mastitis in female rats. The minimal inhibitory concentration (MIC) of BER/CH-NPs and CRE/CH-NPs is 1 mg/kg b.w. BER/CH-NPs and CRE/CH-NPs alone or in combination show significant (P ≤ 0.05) DPPH radical scavenging activity (69.2, 88.5, and 98.2%, respectively) in vitro. Oral administration of BER/CH-NPs and CRE/CH-NPs to mastitis rats significantly (P ≤ 0.05) attenuated TNF-α (22.1, 28.6 pg/ml), IL-6 (33.4, 42.9 pg/ml), IL-18 (21.7, 34.7 pg/ml), IL-4 (432.9, 421.6 pg/ml), and MPO (87.1, 89.3 pg/ml) compared to mastitis group alongside the improvement of MG histopathological findings without any side effect on renal and hepatic functions. Despite promising results with BER and CRE nanoparticles, the study is limited by small-scale trials, a focus on acute administration, and partially explored nanoparticle-biological interactions, with no economic or scalability assessments. Future research should address these limitations by expanding trial scopes, exploring interactions further, extending study durations, and assessing economic and practical scalability. Field trials and regulatory compliance are also necessary to ensure practical application and safety in the dairy industry. In conclusion, the in vitro and in vivo results proved the antioxidant and anti-inflammatory efficacy of BER/CH-NPs and CRE/CH-NPs in low doses with minimal damage to the liver and kidney functions, supposing their promising uses in mastitis treatment.

Review on anti-microbial resistance patterns of staphylococcus aureus isolated from mastitic cow’s milk: Ethiopian context

Aim of this paper is to review antimicrobial resistance profile of Staphylococcus aureus (S. aureus) isolated from mastitic cow milk in Ethiopia between 2013- 2023. S. aureus causes chronic intramammary infections, causing financial losses and challenging antimicrobial therapy globally. In Ethiopia meta-analysis of the pooled prevalence of bovine mastitis was 47.6% showing S. aureus as the major isolates accounting for 13.4% and 16.5% of clinical and subclinical mastitis. In Ethiopia, there are indication of the misuse of antibiotics coupled with the rapid spread of resistant bacterial nature and inadequate surveillance, which contributed to the problem. According to this review resistance profile of S. aureus studied in Ethiopia, the bulk of tested isolates showed alarmingly high levels of resistance to widely used antimicrobial drugs for the treatment of mastitis, particularly penicillin G and tetracycline. Variuos studies warned low susceptibility of S. aureus to commonly used antimicrobials such as penicillin G and tetracycline as a great concern because this antibiotic represents the main antibiotic group recommended for staphylococcal mastitis infection in Ethiopia. If essential steps to stop the indiscriminate use of antibiotics are not implemented, the prevalence of antibiotic-resistant S. aureus could rise posing major risks to both animal and human health. Therefore, conducting regular antimicrobial sensitivity testing before treatment helps select effective antibiotics which reduce the development of resistance to commonly used antibiotics. Further studies should be conducted to detect antimicrobial resistant strains, continiuos surveillance and monitoring of S. aureus to prevent the spread of milk-borne drug-resistant strains throughout communities.

Microbiological and Molecular Investigation of Antimicrobial Resistance in Staphylococcus aureus Isolates from Western Romanian Dairy Farms: An Epidemiological Approach.

Antimicrobial therapy is the most frequently used medical intervention for bovine mastitis in the dairy industry. This study aims to monitor the extent of the antimicrobial resistance (AMR) problem in Staphylococcus aureus in the dairy industry in Western Romania. Twenty farms were selected by random sampling in a transverse epidemiological study conducted across four counties in Western Romania and divided into livestock units. This study assessed the association between the resistance genes to phenotypic expression of resistance and susceptibility. Isolates of S. aureus were identified and q-PCR reactions were used to detect antibiotic resistance genes. One hundred and fifty bovine and 20 human samples were positive for S. aureus. Twenty five percent of bovine isolates (30/120) and none(0/30) of the human isolates were methicillin-resistant S. aureus (MRSA). All isolates were susceptible to fosfomycin, ciprofloxacin, netilmicin, and resistant to ampicillin and penicillin. S. aureus isolates regarded as phenotypically resistant (R) were influenced by the origin of the samples (human versus bovine, χ2 = 36.510, p = 0.013), whether they were methicillin-resistant S. aureus (χ2 = 108.891, p < 0.000), the county (χ2 = 103.282, p < 0.000) and farm of isolation (χ2 = 740.841, p < 0.000), but not by the size of the farm (χ2 = 65.036, p = 0.306). The multiple antibiotic resistance index was calculated for each sample as the number regarded as phenotypically resistant (R)/total antibiotics tested (MARI = 0.590 ± 0.023) was significantly higher (p < 0.000) inmethicillin-resistant S. aureus (0.898 ± 0.019) than non-methicillin-resistant S. aureus (0.524 ± 0.024) isolates. For the antibiotics tested, the total penetrance (P%) of the resistance genes was 59%, 83% for blaZ, 56% for cfr, 50% for erm(B), 53% for erm(C), 57% for mecA and 32% for tet(K). Penetrance can be used as a parameter for guidance towards a more accurate targeting of chemotherapy. P% in S. aureus was strongly positively correlated with the multiple antibiotic resistance index (r = +0.878, p < 0.000) with the potential to use the same limit value as an antibiotic management decision criterion. Considering cow mastitis, the penetrance value combined with the multiple antibiotic resistance index suggests that penetrance could serve as a useful parameter for more precise targeting of chemotherapy for S. aureus.

Relationship of Udder, Flank and Lower Leg Hygiene Scores with Elevated Somatic Cell Count and Prevalence of Subclinical Mastitis in Dairy Cow

Relationship of Udder, Flank and Lower Leg Hygiene Scores with Elevated Somatic Cell Count and Prevalence of Subclinical Mastitis in Dairy Cow

Dielectric relaxation parameters combing raw milk compositions to improve the prediction performance of milk somatic cell count.

Milk somatic cell count (SCC) is an international standard for identifying mastitis in dairy cows and measuring raw milk quality. Milk SCC can be predicted based on dielectric relaxation parameters (DRPs). We noted a high correlation between DRPs and the milk composition content (MCC), and so we hypothesized that combining DRPs with MCC could improve the prediction accuracy of milk SCC. The present study aimed to analyze the relationship between milk SCC, DRPs and MCC, as well as to investigate the potential of combining DRPs with MCC to improve the prediction accuracy of milk SCC. The dielectric spectra (20-4500 MHz) of 276 milk samples were measured, and their DRPs (εl, εh, Δε, τ and σ) were solved by the modified Debye equation. The SCC prediction models were developed using dielectric full spectra, DRPs and DRPs combined with MCC. The results showed the correlations between DRPs (εl, εh, Δε and σ) and MCC (fat, protein, lactose and total solids) were high, and SCC exhibited a non-linear relationship with DRPs and MCC. The 5DRPs + MCC-generalized regression neural network model had the best prediction, with a standard error of prediction for prediction of 0.143 log SCC mL-1 and residual of the prediction bias of 2.870, which was superior to the models based on full spectra, DRPs and near-infrared or visible/near-infrared. The present study has improved the prediction accuracy of milk SCC based on the DRPs combing MCC and provides a new method for dairy farming and milk quality assessment. © 2024 Society of Chemical Industry.

Application of cold plasma therapy for managing subclinical mastitis in cows induced by Streptococcus agalactiae, Streptococcus uberis and Escherichia coli

The primary objective of this study was to assess the effectiveness of cold plasma therapy in managing subclinical mastitis in cows caused by Streptococcus agalactiae, Streptococcus uberis and Escherichia coli. After detection of mastitis pathogens, 38 cows were selected for cold plasma therapy for five days. On the fifth day of treatment, the mastitis agents were re-examined and no causative agents were identified. An additional evaluation conducted 28 days later confirmed the absence of mastitis. Cow productivity, milk composition and quality indicators were assessed at the beginning of the experiment and 32 days from the start (28 days after treatment cessation). After the mastitis treatment, the somatic cell count decreased significantly by between 2.89 and 7.09 times, and the milk yield of the cows at the end of the experiment increased from 0.63 kg per day to 2.82 kg per day (P < 0.01). These results highlight the potential of this innovative approach for managing a prevalent disease that causes substantial losses in the dairy industry. Furthermore, they lay the groundwork for expanded research involving larger sample sizes.

Biological characterization of the phage lysin AVPL and its efficiency against Aerococcus viridans-induced mastitis in a murine model.

A. viridans is a zoonotic pathogen known to cause various diseases, including mastitis in dairy cows. In recent years, there has been an increase in antibiotic-resistant or multidrug-resistant strains of this pathogen. Phage lysins are an effective approach to treating infections caused by multidrug-resistant strains. This study revealed the biological properties and key active sites of the first A. viridans phage lysin named AVPL. AVPL can effectively kill multidrug-resistant A. viridans in pasteurized whole milk. Importantly, 25 μg AVPL significantly alleviates the symptoms of mouse mastitis induced by A. viridans. Overall, our results demonstrate the potential of lysin AVPL as an antimicrobial agent for the treatment of mastitis caused by A. viridans.