Search Results (547)

Background/objectives: severe mastitis is one of the leading causes of mortality in dairy cows. Its primary complication is shock, predominantly associated with systemic inflammatory response syndrome, which remains extremely challenging for practitioners to manage. The average mortality rate is estimated at approximately 25%. Many authors recommend the use of fluoroquinolones for this indication. However, these antibiotics are classified as critically important for human health, and their use requires strict compliance with specific guidelines (bacteriological analysis and antimicrobial susceptibility testing). In addition, some practitioners remain reluctant to use this class of antibiotics in field conditions. Therefore, the present study aimed to evaluate the outcomes of systematic antibiotic therapy using fluoroquinolones in cases of severe mastitis and to identify factors that may influence treatment success. Methods: a total of 323 cows with severe mastitis were enrolled by eight participating veterinary clinics located across different regions of France. The study design included: (i) clinical scoring based on a standardized grid developed by practitioners routinely managing this condition, (ii) bacteriological analysis of milk samples (with antimicrobial susceptibility testing performed when Gram-negative bacteria were isolated), and (iii) post-treatment follow-up consisting of telephone interviews conducted at 5 and 15 days after inclusion. Cows presenting with a clinical score ≥3 (scale 0–36) in association with local signs of mastitis were classified as having severe mastitis and received an injection of 10 mg/kg marbofloxacin along with 2.2 mg/kg flunixin (unless another NSAID had been administered within the previous 24 h). When the clinical score was ≥6, cows additionally received intravenous fluid therapy consisting of 3 L of 7.2% NaCl, supplemented by oral drenching if spontaneous water intake was insufficient. Results: a total of 43 cows died or were euthanized during the study period, corresponding to a mortality rate of 13.3%. The mean clinical score at inclusion was 12.6. The clinical signs most strongly associated with mortality were decubitus and hypothermia at admission. Escherichia coli was isolated in 67.0% of severe mastitis cases, either as a single pathogen (82.9%) or in mixed infections (17.1%). Overall, Gram-negative bacteria (Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, other Gram-negative organisms) were identified in 79.0% of cases. A total of 188 coliform isolates were tested for antimicrobial susceptibility. All isolates (100%) were susceptible to marbofloxacin, as were all tested Gram-negative strains, whereas only 79.9% of E. coli isolates were susceptible to sulfonamide/trimethoprim. Compared with previously published data, the observed mortality rate was lower despite the poor clinical condition of cows at admission. Conclusion: the timeliness of initiating effective antimicrobial therapy appears to be a critical determinant of survival in cows with severe mastitis. Full article

Bovine mastitis causes significant economic losses in the dairy industry. Emerging evidence highlights the critical role of long non-coding RNAs (lncRNAs) in inflammation-associated epigenetic regulation through competing endogenous RNA (ceRNA) networks. In this study, we established a bovine mastitis model in three healthy primiparous Holstein cows by intramammary infection with S. aureus. Infected and control mammary tissue samples were then collected for transcriptomic profiling, which identified 2005 differentially expressed lncRNAs. Among them, BMNCR was significantly upregulated in S. aureus-infected mammary tissues and S. aureus-stimulated BMECs. We evaluated the coding potential of BMNCR and confirmed its non-coding nature. Functional studies in BMECs demonstrated that knockdown of BMNCR suppressed proliferation, promoted apoptosis, and altered the expression of inflammatory factors, including IL-2, IL-6, IL-8, and IL-12. Mechanistically, BMNCR acted as a sponge for bta-miR-145, thereby leading to the derepression of ANO6. Silencing ANO6 partly recapitulated the effects of BMNCR knockdown, impairing proliferation and increasing IL-8 expression. Collectively, these findings suggest that the BMNCR/miR-145/ANO6 axis is involved in the regulation of inflammatory responses and epithelial homeostasis during bovine mastitis, with BMNCR functioning as a protective regulator in this process. Full article

The growing problem of antibiotic resistance poses one of the greatest threats to modern medicine, making the search for new, alternative strategies to treat bacterial infections a matter of priority. The aim of the study was to evaluate the antimicrobial activity of selected postbiotic substances (PS) and nisin against methicillin-susceptible (MS) and methicillin-resistant (MR) strains of coagulase-negative staphylococci (NAS) and mammaliicocci. The study was conducted on 24 strains of coagulase-negative staphylococci and mammaliicocci isolated from milk collected from Holstein-Friesian (HF) cows with subclinical mastitis. In vitro, PS/EMo (100–400 AU/mL) and PS/Eas (100–200 AU/mL) were the most effective, inhibiting the growth of all MS and MR strains of NAS and Mammaliicoccus spp. (100.0%). A high percentage of strains were also sensitive to postbiotic substances produced by Lactococcus lactis subsp. lactis PS/MK2/8 (400–1600 AU/mL), PS/MK1/3 (100–400 AU/mL), and nisin (100–25,600 AU/mL), both in MR strains (94.1%, 82.4%, 88.2%, respectively) and in MS strains (100.0%, 85.7% and 100%, respectively). PS/Esach (100–25,600 AU/mL) inhibited the growth of all strains, including the mecA gene-positive mammaliicocci strains (100.0%), but was slightly less effective against the MS strains (64.7%). The lowest activity was observed with postbiotic substances produced by Enterococcus faecium, PS/4231 (100–1600 AU/mL) and PS/9296 (100–6400 AU/mL), which inhibited the growth of 3 out of 17 MR strains (17.65%). Among the Mammaliicoccus strains with the mecA gene, postbiotic substances derived from strains PS/4231 and PS/9296 inhibited the growth of 42.9% and 28.6% of the strains, respectively. Four tested strains were sensitive to all postbiotic substances (MSC9, MSC11, MSC12 and SCH3). This study confirms that postbiotic substances and nisin inhibit the growth of staphylococci isolated from the milk of cows with subclinical mastitis, including methicillin-resistant strains. Full article

Milk color reflects the optical output of a complex colloidal system governed by protein micelles, fat globules, and serum phase interactions. In this study, we evaluated whether CIE Lab* color parameters can explain variation in milk composition and somatic cell count (SCC) using Lasso-based multiple linear regression and Extreme Gradient Boosting (XGBoost). A total of 119 Holstein milk samples were analyzed for fat, protein, lactose, dry matter, electrical conductivity, freezing point, and SCC, and five color indices (L*, a*, b*, Hue, and Chroma) were used as predictors. Model robustness was evaluated using 10-fold cross-validation and an independent 80/20 train–test split. In regression analyses, Lasso explained 32.7% of protein variation (R² = 0.327), 26.3% of dry matter (R² = 0.263), 22.8% of lactose (R² = 0.228), and 19.1% of fat (R² = 0.191). Spectral tone parameters (a*, Hue, and Chroma) were consistently retained as key predictors, whereas L* showed a limited contribution. SCC exhibited weak direct associations with color traits but was significantly related to electrical conductivity (p < 0.05), indicating inflammation-driven ionic changes rather than pigment effects. In classification analysis (SCC ≥ 200,000 cells/mL), the XGBoost model achieved 74% accuracy and an AUC of 0.69 in the independent test set, with Chroma and electrical conductivity identified as the most influential features. These findings suggest that, among the evaluated color variables, Chroma provided the most relevant information for discriminating SCC status, whereas the overall contribution of milk color traits to compositional prediction remained moderate. Therefore, color-derived measurements should be interpreted as instrument-based optical indicators that may complement, but not replace, conventional milk quality assessments. Full article

Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is a major pathogen responsible for mastitis in dairy cows. It causes persistent and difficult-to-treat mammary infections, leading to reduced milk production. Baicalein, a flavonoid compound, exhibits anticancer, anti-inflammatory, and antibacterial activities; however, its specific mechanism of action against GBS remains unclear. This study aimed to investigate the mechanism by which baicalein inhibits GBS invasion of bovine mammary epithelial cells (bMECs). The results showed that baicalein at concentrations of 4 μg/mL or higher effectively inhibited 50% of the invasion of bMECs by GBS strain HB31 and exerted a concentration-dependent inhibitory effect on bacterial adhesion. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of baicalein against HB31 were both greater than 1024 μg/mL. Therefore, the antibacterial effect of baicalein alone may not fully account for its mechanism; other pathways likely contribute to the reduced invasiveness of GBS. To elucidate the mechanism by which baicalein inhibits GBS invasiveness, this study investigated both bacterial metabolism and gene expression. Metabolomic analysis revealed that baicalein treatment led to the downregulation of amino acid metabolites, including alanine and aspartic acid, as well as nucleotide metabolites such as adenine and UMP in GBS HB31. Additionally, the NADH/NAD⁺ ratio increased while ATP levels decreased, indicating that the overall metabolic activity of GBS was suppressed. Transcriptomic analysis focused on changes in invasion-associated virulence genes. The results showed that the expression of pbsP, an invasion-associated virulence gene, was significantly reduced, while the expression of hylB and cfb showed downward trends that did not reach statistical significance. In contrast, the expression of cylE and the two-component system vicKR was upregulated. The upregulation of cylE may be related to baicalein-induced oxidative stress in HB31. Furthermore, HB31 suppressed Nrf2-HO-1 mRNA expression, whereas baicalein activated the Nrf2 signaling pathway and reduced HB31-induced IL-6 and NF-κBmRNA expression. These findings provide new insights for the development of anti-virulence therapeutic strategies targeting GBS. Full article

Mastitis is a common disease in dairy cows, mainly caused by Staphylococcus aureus and Escherichia coli. Berberine (BBR) has antibacterial and anti-inflammatory potential, but its application is limited due to poor oral absorption and difficulty in reaching mammary tissue. To address this, this study developed a BBR-loaded composite ethosome hydrogel (BBR-CEH) to achieve targeted mammary delivery through local transdermal administration. The experimental results showed that BBR-CEH has good chemical stability and biosafety. Subsequently, a mouse mastitis model was established by intraductal injection of 50 µL of bacterial mixture (E. coli:S. aureus = 1:1, each at 1 × 10⁷ CFU/mL). The results showed that after BBR-CEH treatment, the mRNA expression of TNF-α (tumor necrosis factor-alpha), IL-6 (interleukin-6), and IL-1β (interleukin-1 beta) was significantly decreased, the mRNA expression of ZO-1 (zonula occludens-1), Occludin, and Claudin-4 was significantly increased, and Bax/Bcl-2 (Bcl-2-associated X protein/B-cell lymphoma 2) was significantly reduced (p < 0.01), indicating alleviation of mastitis by reducing inflammation, improving tight junctions, and inhibiting apoptosis. Finally, network pharmacology and in vivo experiments confirmed that its mechanism involves the NF-κB (nuclear factor kappa-B) and PI3K/Akt (phosphoinositide 3-kinase/protein kinase B) pathways. Thus, topical BBR-CEH may represent a promising new strategy for mastitis treatment. Full article

To date, the problem of mastitis in cattle remains relevant for both the industrial sector and scientific research. Despite numerous active investigations, the causes of this disease have not been fully established. It is postulated that several factors may be involved, such as bacterial pathogens, animal husbandry practices, and weather and climatic conditions. In this study, we selected cows from farms in Yakutia to investigate microbial isolates present in the milk of cows affected by mastitis and treated with antibiotics. Five identified Staphylococcus aureus isolates were investigated using whole-genome sequencing (Illumina sequencing and nanopore sequencing), followed by analysis of virulence factors in the genomes and cultural properties of the isolates. The profile of S. aureus virulence genes (exotoxins, cytotoxins, superantigen-like proteins, adhesins) was identified via WGS. Hemolysin gene (hla) was detected in all isolates. An investigation of the cultural properties of the isolates, specifically through hemolysis of rabbit erythrocytes and Western blot analysis of the culture liquid of S. aureus, revealed different expression levels of alpha-hemolysin among the strains. One isolate (17-21) exhibited the highest secretion level of about 320 ± 37 ng, both in the hemolysis test and immunoblotting assay. An investigation of the isolates’ antibiotic resistance showed that all isolates exhibited multidrug resistance, as confirmed by the presence of antibiotic resistance genes in these isolates. One isolate (7-7) exhibited the broadest range of phenotypic resistance and was resistant to all tested antibiotics (except clindamycin). Phylogenetic analysis suggested that the evolution of these isolates occurred independently in their respective ecological niches, although their transfer from cattle to humans, and vice versa, is possible. Isolates 7-7, 18-22, 33-40, and 35-42 are most typical to Yakutian cattle, while isolate 17-21 might have been introduced from a different region. To the best of our knowledge, this is the first in-depth study into a range of S. aureus isolates associated with mastitis infection in Yakutian cattle. Full article

Bovine mastitis is a multifactorial inflammatory disease primarily characterized by inflammatory cell infiltration and the destruction of mammary alveoli. It is a major cause of reduced milk yield and quality. The imbalance between antioxidant defenses and the generation of reactive oxygen species (ROS), which occurs due to the high metabolic activity of the mammary gland during the periparturient period, increases the incidence of mastitis. During early lactation, especially in high-yielding dairy cows, the massive synthesis and secretion of milk increase the energy demand of mammary tissue, leading to excessive ROS accumulation. This results in cell membrane disruption and, ultimately, antioxidant dysfunction in the mammary tissue. This study established an in vitro oxidative stress model by treating bovine mammary epithelial cells (BMECs) with 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH). The optimal concentration of 1000 μmol/L AAPH was determined using the CCK-8 assay. Model validation showed that, compared to the control group, ROS levels were significantly elevated (p < 0.001) and mitochondrial membrane potential was significantly decreased (p < 0.001) in the AAPH-treated group. Transmission electron microscopy (TEM) analysis revealed that AAPH treatment caused ultrastructural damage, including reduced microvilli, mitochondrial swelling, disappearance of cristae, and vacuolization. Mechanistic studies demonstrated that AAPH treatment significantly upregulated the mRNA and protein expression of AMPK, HMOX-1, mTOR, NOS, and SOD (p < 0.001), while significantly downregulating CYP1A1 expression (p < 0.001). Pretreatment with N-acetylcysteine (NAC) effectively alleviated the oxidative stress damage caused by AAPH. This study successfully established an in vitro AAPH-induced oxidative stress model in BMECs and revealed its molecular mechanism of cellular damage. The damage occurs through modulation of the AMPK/mTOR signaling pathway and the regulation of antioxidant-related gene expression. Full article

Dairy cows typically respond to stressors by altering their behavior, such as reducing eating time (ET) and rumination time (RT). Although declines in milk yield (MY) have been extensively studied, models to quantify perturbations in ET and RT are still lacking. This study adopts a smoothing approach to identify and characterize perturbations in MY, ET, and RT in response to the main primary stressors, heat stress (HS), lameness (L), and mastitis (M), while evaluating the influences of parity and stage of lactation. A total of 350 Italian Simmental cows were monitored in farms equipped with automatic milking systems and accelerometers. Within this population, cows with a lactation period of at least 150 days were selected. A double-curve smoothing model (λ = 100 and λ = 10,000) was applied to calculate response and recovery times and to quantify production and feeding behavior losses. The results indicate that L causes the longest (30.6 d and 28.8 d, respectively) perturbations for both MY and ET. While L caused the greatest loss in milk production (14.7 kg), HS resulted in the greatest losses regarding feeding behavior (ET: 175.2 min and RT: 210.3 min). In general, M had a lower impact, likely due to the timeliness of treatments. Primiparous cows showed faster responses to stress but slower recovery times compared to multiparous ones. However, multiparous cows exhibited greater total MY losses. The method proved effective for quantifying resilience and opens new perspectives in health monitoring, allowing for the identification of both economic loss and each animal’s capacity to cope with pathological and environmental events, improving the overall sustainability of the dairy farm. Full article

The dry period is a critical window of susceptibility to intramammary infection in dairy cows, yet the metabolic environment of the mammary gland during this phase remains largely uncharacterized. The objective of this study was to profile the metabolome of bovine dry secretion fluid from quarters with subclinical mastitis (SCM; SCC ≥ 200,000 cells/mL) and healthy quarters (H; SCC < 200,000 cells/mL) on day 2 (D2) and day 21 (D21) of the dry period (n = 10 per group quarters per group, drawn from a cohort of 41 enrolled Holstein dairy cows) using high-performance chemical isotope labeling liquid chromatography–mass spectrometry (CIL-LC–MS). A total of 474 metabolites were positively identified. At D2, 186 metabolites differed significantly between SCM and H quarters, with dipeptides dominating the upregulated metabolites, indicating active proteolysis in infected quarters. Norepinephrine was the most significantly depleted metabolite (FC = 0.27, p = 3.37 × 10⁻⁷), pointing to local catecholamine exhaustion. By D21, only 36 metabolites remained altered, representing an 80.6% attenuation of the SCM signature. Interestingly, temporal changes from D2 to D21 far exceeded disease-related differences, with 316 metabolites shifting in both SCM and healthy quarters, establishing mammary involution as the dominant metabolic event during the dry period. Principal component and PLS-DA analyses confirmed that time, not disease status, was the primary driver of metabolic variation. Pathway analysis revealed significant perturbations in amino acid metabolism, glyoxylate and dicarboxylate metabolism, and tryptophan metabolism. These findings provide the first comprehensive metabolomic map of bovine dry secretion, reveal that subclinical mastitis superimposes a proteolytic and neuroimmune disruption onto the involution process, and identify candidate biomarkers for early detection of intramammary infection during the dry period. Full article

Mastitis, a disease associated with milk production with multiple etiologies, causes significant economic losses among dairy farmers worldwide. This study aimed to detect mastitis using thermal images of the udder obtained during the milking phase from 500 Holstein dairy cows with the aid of an Artificial Neural Network (ANN). Mastitis levels were classified based on the California Mastitis Test (CMT) scores using somatic cell count (SCC) as the output variable. The dataset was divided into training (70%), validation (15%), and test (15%) subsets. RGB (Red, Green, Blue) thermal images were used to construct the input matrices. The model achieved correlation coefficients (R) of 0.91, 0.97, and 0.97 for the training, validation, and test datasets, respectively. The close agreement between validation and test performances indicates the absence of overfitting and demonstrates strong generalization capability of the proposed model. These findings suggest that artificial neural networks combined with thermal imaging can provide high-quality and reliable results for mastitis detection. Full article

The effects of reproductive technologies, namely, artificial insemination (AI) and multiple ovulation embryo transfer (MOET), on the production, health, and longevity of Holstein–Friesian cows were evaluated. Data were obtained from the time period between 2017 and 2024 on a Hungarian dairy farm and consisted of 1783 cows (1544 AI and 239 MOET). Deep-frozen semen from identical bulls was used for both the AI and MOET groups. Disease incidence, productive life, and early-lactation milk production phenotypes were collected in these cows. MOET cows demonstrated significantly higher milk yield during the first 100 days of lactation but had a 43.9% greater risk of culling compared with AI cows (p < 0.05). Metabolic and reproductive disorders were the most common reasons for culling cows, with increased frequency of health issues correlating with higher culling risk ratios (p < 0.05). While MOET cows showed lower incidences of metabolic disorders, reproductive problems, and mastitis, their shorter productive lifespan likely limited overall disease exposure. Nevertheless, when MOET cows experienced illness, the impact was more severe, particularly in relation to metabolic issues (p < 0.05). These findings highlight trade-offs between improved genetic potential and health resilience in MOET-derived cows. Despite their higher productivity, their management may require greater health vigilance. This study offers practical insights for dairy producers in selecting reproductive strategies to balance genetic gain, herd health, and longevity under intensive production systems. Full article

Mastitis in dairy cows, caused by pathogens such as Staphylococcus aureus, Escherichia coli, and Candida albicans, leads to substantial economic losses and contributes to antimicrobial resistance, emphasizing the need for natural alternatives. This study assessed the phytochemical composition, antioxidant activity, and in vitro antimicrobial effects of ethanol extracts from ten medicinal plants, including Populus balsamifera buds, Syzygium aromaticum, and Humulus lupulus, as well as two multi-component plant mixtures and commercial products against reference strains and field isolates of mastitis pathogens. Extracts exhibited total phenolic contents ranging from 2.5 to 43.0 mg GE/g, with Populus balsamifera and Syzygium aromaticum demonstrating the strongest DPPH radical scavenging activity (IC₅₀ 1.89–2.9 mg/g extract). Disc diffusion assays demonstrated broad-spectrum inhibition, particularly for Populus balsamifera (15.1–19.1 mm inhibition zones) and Humulus lupulus (9.0–18.4 mm) against key pathogens; phenolic and flavonoid contents positively correlated with antimicrobial activity (r = 0.63–0.99, p < 0.001). Multi-component mixtures provided consistent broad-spectrum effects (12.6–17.2 mm). These phenolic-rich plant extracts represent promising alternatives to reduce antibiotic use in dairy mastitis management. Full article

Hafnia alvei, which belongs to the Enterobacteriaceae family, has been occasionally documented in animal infections but is still not well characterized in the context of bovine mastitis. This research examined the prevalence and antimicrobial resistance characteristics of H. alvei in dairy cows suffering from subclinical mastitis in South Africa’s Free State Province. In the Thabo Mofutsanyana District, a total of 174 milk samples were obtained from cows on six different dairy farms. The California Mastitis Test (CMT) was used to screen for subclinical mastitis, and somatic cell count was used to confirm it. Standard culture methods were used for bacterial isolation, and presumptive Enterobacteriaceae isolates were identified through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Out of the 174 samples, 84 (48.2%) tested positive for CMT, and 68 (39.1%) met the SCC criteria for subclinical mastitis at a cow level, while 96/336 (28.5%) were infected at a quarter level. Of the 100 presumptive Enterobacteriaceae isolates, 33 (33.0%) were identified as H. alvei (p = 0.0034). Antimicrobial susceptibility testing showed that 50% of the isolates were resistant to penicillin, followed by tetracycline and erythromycin with 25% and 10%, respectively. Furthermore, the results showed that 17 (51.5%) isolates exhibited multidrug-resistant profiles. The results suggest that H. alvei could be a contaminant in raw milk associated with bovine subclinical mastitis in this area, necessitating additional epidemiological research that includes healthy matched controls. Full article

When LLMs are applied in the veterinary field, they often produce serious hallucinations and logical restrictions, especially in the accurate diagnosis of bovine disease, where accuracy is crucial. To meet this challenge, this paper proposes GraphRAG-Vet, a Knowledge Graph Retrieval-Augmented Generation framework specifically designed for the dairy industry. First, we constructed a domain knowledge map comprising 2500 elements and 3000 relationships, covering high-frequency diseases in cows such as mastitis and ketosis. Second, the semantic-to-password parsing module is designed to retrieve disease symptom subgraphs from the Neo4j database accurately. Finally, the hard constraint injection mechanism is introduced to force LLMs to generate diagnoses strictly in accordance with the retrieved graph context, thereby implementing the “refuse to answer” function for foreign queries. The experimental results showed that GraphRAG-Vet achieved 100% accuracy in diagnosing core infectious diseases and had an almost-zero hallucination rate compared with baseline LLMs. This study provides a reliable, low-resource solution for automated veterinary consultation. Full article