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(1) Background: Information is lacking on small ruminant lentivirus (SRLV) status, prevalence, risk factors, and control measures for mastitis in California ewes. The goal of this survey was to outline characteristics of the sheep industry in California related to udder health and mastitis management. (2) Methods: An online survey consisting of 48 questions was completed by respondents between April 2022 and February 2023. Descriptive analysis and chi-squared tests were conducted to evaluate associations between variables. A multiple correspondence analysis (MCA) of general management practices, udder health management, and flock demographics was performed to assess clustering. A subset of respondents (20) participated in SRLV serology testing. (3) Results: Seventy-one completed surveys were submitted. The MCA showed two clusters. Larger flock sizes, the use of breeding ewes for meat or wool production or contract grazing, and extensive management practices were more closely related to >5% udder abnormalities per lactation and ≥5% orphan lambs. The flock-level seroprevalence of SRLV was 75% (15/20), and ewe-level seroprevalence was 14.1% (183/1106). (4) Conclusions: The results of this study highlight areas that need further research, such as exploring differences in mastitis and SRLV incidences among management systems, the efficacy of mastitis treatments, and education on critical timepoints for mastitis diagnosis and control.

Simple Summary: Dairy cows commonly suffer from two major health problems, mastitis (udder inflammation) and lameness (difficulty walking), which cause significant pain and reduce milk production. These conditions are mainly caused by bacteria; however we do not fully understand how these bacteria adapt and spread. In our work, we focused on the genetic material of four important bacterial species that cause the mentioned diseases, analyzing over 4300 bacterial samples worldwide. We found that these bacteria showed different genomic diversity patterns depending on where they originated, suggesting they adapt to local conditions. Some bacteria also showed signs of becoming resistant to common treatments, which is concerning for animal health. We found that two bacterial species, Escherichia coli and Staphylococcus aureus, were much more common and varied than the others. These findings help farmers and veterinarians better understand how these diseases spread and develop. This knowledge can lead to better treatments and prevention strategies, ultimately improving cow welfare and dairy farm productivity while reducing economic losses in the dairy industry. This study presents a comprehensive genomic reanalysis of major bacterial pathogens causing bovine mastitis and lameness, focusing on Staphylococcus aureus, Escherichia coli, Fusobacterium necrophorum, and Treponema phagedenis. Through our analysis of 4326 bacterial genomes from global databases, we identified distinct patterns in genomic diversity, virulence factors and antimicrobial resistance genes across these species. E. coli showed the highest genomic diversity with 3779 isolates, of which 98% exhibited high-quality genome sequences. Similarly, S. aureus demonstrated significant genomic plasticity across 524 isolates, with 99.8% classified as high-quality genomes. Geographical analysis revealed distinct regional variations in strain distribution, with North America contributing 45.3% of all isolates, followed by Asia (21.2%) and Europe (18.1%). Furthermore, we identified novel virulence mechanisms and resistance patterns specific to each pathogen, with particular emphasis on the evolution of antimicrobial resistance genes. Our findings provide crucial insights into pathogen adaptation and host–microbe interactions, suggesting the need for region-specific intervention strategies. These results have significant implications for developing targeted therapeutic approaches and improving bovine health management practices. [ABSTRACT FROM AUTHOR]

Background Bovine mastitis is the costliest disease in the dairy sector and the main cause of antibiotic use in dairy cattle, potentially contributing to the antimicrobial resistance crisis. Antimicrobial peptides (AMPs) offer promise as antibiotic alternatives for controlling mastitis pathogens. Methods The efficacy of five AMPs (Lynronne-1 [Lyn-1], Lynronne-2 [Lyn-2], Bovicin HC5, AMP 660, and AMP 1043) and two bioactive compounds (disodium ethylenediaminetetraacetic acid [EDTA] and glycerol monolaurate) was assessed against a range of 35 mastitis-causing pathogens. The fractional inhibitory concentrations index (FICI) was calculated to determine the interaction effect and values ≤0.5 were indicative of synergism. Time-dependent killing assays were performed to assess bactericidal efficacy of the combination. Cytotoxicity was evaluated using the MTT assay and haemolytic activity was assessed against fresh bovine erythrocytes. Results Lyn-1 and EDTA exhibited the highest broad spectrum antimicrobial activity and reduced bacterial growth (OD600 nm) by 95.1% and 86.9%, respectively. FICI values ranged from 0.1 to 0.5, indicating synergism. The combination of lyn-1 (0.03 mg/mL) and EDTA (1.02 mg/mL) exhibited higher antimicrobial activity against all bacterial strains, at significantly lower concentrations than each compound individually. Lyn-1-EDTA combination reduced viable population by >10 000-fold within 12 h. The combination was non-haemolytic in concentrations up to 8-fold the established MIC values (P  > 0.05), although cytotoxic effects were observed at concentrations above MIC (P  < 0.01). Conclusions These findings highlight the therapeutic potential of Lyn-1 and Lyn-1-EDTA for developing antibiotic-free formulations to combat contagious and environmental mastitis pathogens and treat udder infections. [ABSTRACT FROM AUTHOR]

Bovine mastitis is the most widespread disease that causes financial loss in the dairy industry. Staphylococcus aureus is a well-researched multidrug-resistant opportunistic bacterium that is frequently linked to subclinical mastitis and causes significant economic losses. A further problem in the management of S. aureus infections is its capacity to form biofilms; bacteria inside biofilms exhibit greater resistance to antimicrobials than planktonic cells. The most effective method for controlling mastitis is antibiotic therapy. Cloxacillin (CLX), ampicillin, and ceftiofur are currently the most often utilized drying treatments for dairy cattle. We have evaluated the therapy efficiency of cloxacillin-loaded chitosan nanoparticles (CLX-CS NPs) as well as the relationship between biofilm production, gene profile and the type of trial group (CLX and CLX-CS NPs) against S.aureus isolated from milk samples of cows diagnosed with subclinical mastitis. Investigation of phenotypic biofilm production showed that majority of the S. aureus isolates extracted from milk were producers of biofilm. Cloxacillin-loaded chitosan nanoparticles were able to significantly decrease the MIC (p < 0.05) and MBC values compared to cloxacillin. The relationship between the gene profile and the types of trial groups shows that coating cloxacillin with chitosan nanoparticles (CS-NPs) was able to reduce the MIC and MBC value in all nine gene profile groups. These findings indicate that administration of cloxacillin-loaded CS-NPs in the treatment of mastitis may improve cloxacillin therapeutic properties and could act as a potential alternative to the cloxacillin antibiotic for the treatment of bovine mastitis. [ABSTRACT FROM AUTHOR]

Escherichia coli (E. coli) is commonly found in dairy farms and can invade mammary gland tissue, often causing acute clinical mastitis. Mammary infections with E. coli have shown a wide range of clinical signs, causing abnormal appearance of the milk, udder inflammation and systemic signs of illness. Circular RNA is a class of endogenous non-coding RNA that plays an important role in the occurrence and development of various inflammatory diseases. However, there is little information on the circRNA associated with bovine mastitis. In this study investigated the involvement of circRNAs in bovine mastitis through the construction of an E. coli-infected bovine mastitis model by injecting of E. coli into the mammary gland of dairy cows, using healthy gland mammary tissue as a control (M_C). High-throughput RNA-seq was performed on the E. coli-infected mammary gland tissue (M_E) and differentially expressed circRNAs between theM_C and M_E groups, followed by an analysis of their potential functions using bioinformatics methods. A total of 164 differentially expressed circRNAs were identified, including 92 downregulated circRNAs and 72 upregulated circRNAs. As shown by Gene Ontology enrichment analysis these DE circRNAs were mostly enriched in ras protein signal transduction, cytoplasmic vesicle parts, and enzyme binding, and Kyoto Encyclopedia of Genes and genome singal pathway enrichment analysis indicated significant associations with phagosome signal pathway. Additionally, the expression of bovine mastitis-related circRNAs, including novel_circRNA_0000128, novel_circRNA_0011103, novel_circRNA_0012656, novel_circRNA_0015099, novel_circRNA_005648, novel_circRNA_000074, and novel_circRNA_0011796 were verified via quantitative reverse-transcription polymerase chain reaction (RT-qPCR). These results provide a new direction for further investigation of the molecular mechanisms underlying bovine mastitis. [ABSTRACT FROM AUTHOR]

Tight junctions (TJs) are the key determinant of barrier function in the mammary gland, with their disruption being associated with the pathogenesis and progression of mastitis, especially in the case of Staphylococcus aureus (S. aureus) infection. This study investigated whether selenium (Se) could attenuate S. aureus-induced mastitis by inhibiting inflammation and protecting mammary gland TJs in mice. The expression profiles of S. aureus-infected gland tissues derived from the gene expression omnibus dataset were analyzed. We found cytokine production, cell junctions, the nuclear transcription factor-κB (NF-κB) signalling pathway, and inflammatory responses associated with the differentially expressed genes, as revealed by Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment analyses. Se reduced the mRNA expression and production of inflammatory cytokines, including tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and decreased phosphorylation levels of the NF-κB complex. Moreover, Se alleviated structural damage and microvillus injury in mammary glands. Immunohistochemical staining revealed that Se increased the expression of Claudin-3; Western blot analysis revealed increased protein levels of Occludin and Tricellulin in the group supplemented with dietary Se. In summary, Se counteracted TJ disruption and attenuated NF-κB-mediated inflammatory responses in S. aureus-infected mouse mammary glands. [ABSTRACT FROM AUTHOR]

Mastitis, an inflammatory condition affecting more than 25% of breastfeeding women, is usually associated with reduced milk secretion, pain, and discomfort, which often leads to early cessation of breastfeeding. Although the etiology of mastitis is multifactorial, a pro-inflammatory state of the mammary gland might be a risk factor. However, changes in milk composition, and specifically in the milk immune profile, prior to and during mastitis have not been well described. To help close this research gap, we documented the immune profiles of milk produced by both breasts of 10 women experiencing clinical (CM) and 8 women experiencing subclinical (SCM) mastitis during the week of sign/symptom development as well as the week prior and compared them with milk produced by 14 healthy controls. CM was defined as having signs/symptoms of mastitis, whereas SCM was presumed if the participant did not have signs/symptoms of CM, but her milk had a somatic cell count >400,000 cell/mL and/or sodium-to-potassium (Na/K) ratio >1.0. Concentration of 36 immune factors (including immunoglobulins, cytokines, chemokines, and growth factors) was quantified via immunoassays. Milk produced by women who developed CM had distinct immune profiles the week prior to diagnosis, particularly elevated concentrations of pro-inflammatory cytokine IL-1β and regulatory cytokines IL-2, IL-4 and IL-10. In contrast, immune profiles in milk produced by women with SCM did not differ from that produced by healthy women or those with CM the week prior to mastitis onset. Once mastitis appeared, marked changes in milk's immune profile were observed in both CM and SCM groups. CM was characterized by elevated concentrations of 27 compounds, including pro-inflammatory cytokines (IL-1β, IL-1ra, and TNFα) and chemokines (including IL-8, eotaxin, IP-10, MCP-1, MIP1α, and MIP1β), compared to healthy controls. Milk's immune profile during SCM was intermediate, showing higher levels of IL-6, IFNγ, and MCP-1 compared to healthy controls, suggesting a milder, more controlled immune response compared to CM. Only milk produced by the mastitis-affected breast had altered immune profiles. Further research is needed to determine if these differences in milk's immune profiles can be used to improve mastitis risk prediction prior to onset of symptoms. [ABSTRACT FROM AUTHOR]

Early detection of bovine mastitis-causing pathogens is necessary for treatment. As culturing methods are time-consuming, a more rapid detection technique is required. This study investigated the sensitivity, specificity, and detection limit of Gram staining of milk precipitates (milk Gram stain, MGS) to detect bovine mastitis-causing pathogens in milk, as well as the potential of MGS to diagnose inflammation by counting polymorphonuclear leukocytes (PMN). MGS was performed on spontaneous mastitis cases. Culture methods were also used as reference standards to calculate the sensitivity, specificity, and bacterial load in milk to determine the detection limit of MGS. PMN in the mastitic milk were counted using Gram staining. Further, somatic cell counts (SCC), interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, IL-10 and serum amyloid A (SAA) concentrations in mastitic milk were measured using cell counting and enzyme-linked immunosorbent assay. The sensitivity and specificity for all pathogens were 0.62 and 0.90, for Gram-positive were 0.67 and 0.90, and for Gram-negative were 0.50 and 1.00, respectively. The detection limits for Gram-positive and Gram-negative bacteria were 1,560 and 4,680 cfu/mL, respectively. SCC were significantly positively correlated with PMN, milk IL-6, TNF-α, and SAA concentrations, whereas PMN were significantly negatively correlated with milk IL-10 concentration. Our results suggest that MGS may be applied as a rapid method to identify causal pathogens of mastitis before culture results are determined and may also estimate inflammatory status which cannot be detected with SCC. Further clinical trials are required to elucidate whether MGS is useful in clinical veterinary settings. [ABSTRACT FROM AUTHOR]

Simple Summary: Prepartum vaccinations of cows are performed to boost colostral antibodies available to calves in the first weeks of life. While beneficial effects of the vaccine for calves are well known, less has been investigated on its effects on the cow during the sensitive period around calving. There is evidence that vaccines have non-specific effects, including altered susceptibility to infectious diseases other than the targeted pathogens and involve the innate immune response of the vaccinated animal. Therefore, this study analyzed data from 73,378 cows on 20 farms in Germany to evaluate the effects of prepartum vaccination against neonatal calf diarrhea on mastitis, somatic cell count, and milk production. The results demonstrated that herd management had the highest influence, while prepartum vaccination had no significant impact on mammary health and milk yield. These findings suggest that prepartum vaccination does not compromise mammary health or milk productivity. Further research is recommended to explore non-specific vaccine effects on other organ systems, diseases, and production metrics in dairy cows. Prepartum vaccinations against neonatal calf diarrhea pathogens are administered in late pregnancy to provide passive immunity to calves through protective colostral antibodies. Potential non-specific effects of the vaccine on maternal innate immune responses and disease susceptibility during the sensitive transition period have not been addressed so far. In this retrospective study, data from 73,378 dairy cows on 20 farms in Germany were analyzed, using linear mixed-effects regression, quantile regression, and decision-tree-algorithms, to investigate the effects of prepartum vaccination on mammary health and milk yield by comparing non-vaccinated and vaccinated transition periods. Herd management-related factors were found to be most influential for mammary health and milk yield. Vaccinated cows were not significantly more likely to develop mastitis and did not have significantly different somatic cell counts and milk yields compared to non-vaccinated cows. Healthy primiparous cows with and without vaccination had similar energy-corrected milk yields. The study concludes that prepartum vaccination against calf diarrhea has no significant effects on mammary health and milk yield. Further research is recommended to investigate potential non-specific vaccine effects on other organ systems, infectious diseases, and production metrics of the dairy cow. [ABSTRACT FROM AUTHOR]

Simple Summary: In the last decade, buffalo farming has been attracting the interest of the research communities because of its high resilience in the current climate change context. Over their lifetime, animals face a range of infectious and non-infectious stressors on which successful recovery of their optimal performance may depend on different psychological conditions. Enabling both innate and adaptive immune responses, through the secretion of pro- and anti-inflammatory cytokines, plays a key role in the onset or progression of disease. This review describes the complex immune competence of the buffalo in the presence of the most prevalent infectious stressors, including mastitis, endometritis, and non-infectious stressors such as climate change-induced heat stress. Immune competence is a critical aspect of protecting animals from the negative consequences of disease. The activation of the immune response from inflammation is part of adaptive homeostasis that serves to eliminate danger, induce tissue repair, and restore tissue homeostasis. Therefore, the main goal for the organism is to control both the induction and suppression of inflammation and resist the onset of disease. In this condition, modulators of inflammatory responses are produced, including small proteins called cytokines, which exert a pro- or anti-inflammatory action in a context-dependent manner. Indeed, the cytokine profile could be considered a useful biomarker to determine the pathophysiology of certain diseases, such as mastitis, endometritis, change-induced heat stress, and zoonoses. Recently, buffalo breeding has attracted the interest of the research communities due to their high resilience; however, little is known about the immune mechanism activated under specific stressors. This review describes the complex immune competence of the buffalo in the presence of the most common infectious and non-infectious stressors. In addition, a brief description of methods for early diagnosis of disease using cytokine quantification will be introduced. [ABSTRACT FROM AUTHOR]

Objective: Non-puerperal mastitis (NPM) is an inflammatory breast disease affecting women during non-lactation periods, and it is prone to relapse after being cured. Accurate prediction of its recurrence is crucial for personalized adjuvant therapy, and pathological examination is the primary basis for the classification, diagnosis, and confirmation of non-puerperal mastitis. Currently, there is a lack of recurrence models for non-puerperal mastitis. The aim of this research is to create and validate a recurrence model using machine learning for patients with non-puerperal mastitis. Methods: We retrospectively collected laboratory data from 120 NPM patients, dividing them into a non-recurrence group (n = 59) and a recurrence group (n = 61). Through random allocation, these individuals were split into a training cohort and a testing cohort in a 90%:10% ratio for the purpose of building the model. Additionally, data from 25 NPM patients from another center were collected to serve as an external validation cohort for the model. Univariate analysis was used to examine differential indicators, and variable selection was conducted through LASSO regression. A combination of four machine learning algorithms (XGBoost、Logistic Regression、Random Forest、AdaBoost) was employed to predict NPM recurrence, and the model with the highest Area Under the Curve (AUC) in the test set was selected as the best model. The finally selected model was interpreted and evaluated using Receiver Operating Characteristic (ROC) curves, calibration curves, Decision curve analysis (DCA), and Shapley Additive Explanations (SHAP) plots. Results: The logistic regression model emerged as the optimal model for predicting recurrence of NPM with machine learning, primarily utilizing three variables: FIB, bacterial infection, and CD4+ T cell count. The model showed an AUC of 0.846 in the training cohort and 0.833 in the testing cohort. The calibration curve indicated excellent calibration of the model. DCA revealed that the model possessed favorable clinical utility. Furthermore, the model effectively achieved in the external validation group, with an AUC of 0.825. Conclusion: The machine learning model developed in this study, serving as an effective tool for predicting NPM recurrence, aids doctors in making more individualized treatment decisions, thereby enhancing therapeutic efficacy and reducing the risk of recurrence. [ABSTRACT FROM AUTHOR]