Subclinical Mastitis In Dairy Cows Research Articles

Identifying Predictive Biomarkers of Subclinical Mastitis in Dairy Cows through Urinary Metabotyping.

Mastitis is a significant infectious disease in dairy cows, resulting in milk yield loss and culling. Early detection of mastitis-prone cows is crucial for implementing effective preventive measures before disease onset. Current diagnosis of subclinical mastitis (SCM) relies on somatic cell count assessment post-calving, lacking predictive capabilities. This study aimed to identify metabolic changes in pre-SCM cows through targeted metabolomic analysis of urine samples collected 8 wks and 4 wks before calving, using mass spectrometry. A nested case-control design was employed, involving a total of 145 multiparous dairy cows, with disease occurrence monitored pre- and postpartum. Among them, 15 disease-free cows served as healthy controls (CON), while 10 cows exclusively had SCM, excluding those with additional diseases. Urinary metabolite profiling revealed multiple alterations in acylcarnitines, amino acids, and organic acids in pre-SCM cows. Metabotyping identified 27 metabolites that distinguished pre-SCM cows from healthy CON cows at both 8 and 4 wks before parturition. However, only four metabolites per week showed significant alterations (p < 0.005). Notably, a panel of four serum metabolites (asymmetric dimethylarginine, proline, leucine, and homovanillate) at 8 wks prepartum, and another panel (asymmetric dimethylarginine, methylmalonate, citrate, and spermidine) at 4 wks prepartum, demonstrated predictive ability as urinary biomarkers for SCM risk (AUC = 0.88; p = 0.02 and AUC = 0.88; p = 0.03, respectively). In conclusion, our findings indicate that metabolite testing can identify cows at risk of SCM as early as 8 and 4 wks before parturition. Validation of the two identified metabolite panels is warranted to implement these predictive biomarkers, facilitate early intervention strategies, and improve dairy cow management to mitigate the impact of SCM. Further research is needed to confirm the efficacy and applicability of these biomarkers in practical farm settings.

Performance comparison of machine learning models used for predicting subclinical mastitis in dairy cows: Bagging, boosting, stacking, and super-learner ensembles versus single machine learning models

Mastitis has a substantial impact on the dairy industry across the world, causing dairy producers to suffer losses due to the reduced quality and quantity of produced milk. A further problem, related to this issue, is the excessive use of antibiotics that leads to the development of resistance in different bacterial strains. The growing consumer awareness oriented toward food safety and rational use of antibiotics has promoted the search for new methods of early identification of cows that may be at risk of developing the disease. Subclinical mastitis does not cause any visible changes to the udder or milk, and therefore it is more difficult to detect than clinical mastitis. The collection of large amounts of data related to milk performance of cows allows using machine learning (ML) methods to build models that could be used for classifying cows into healthy and at risk of subclinical mastitis. The data used for the purpose of this study included information from routine milk recording procedures. The data set consisted of 19,856 records of 2,227 Polish Holstein-Friesian cows from 3 herds. The authors decided to use the approach of building ensemble ML models, in particular bagging, boosting, stacking and super learner models, and comparing them for accuracy of identification of disease-affected cows against single ML models based on the Support Vector Machines, Logistic Regression, Gaussian Naïve Bayes, k-Nearest Neighbors and Decision Tree algorithms. The models were trained and evaluated based on the information recorded for herd 1 and using an 80:20 train-test split ratio according to animal ID (to avoid data leakage). The information recorded for herds 2 and 3 was only used to evaluate on unseen data models developed using the herd 1 data set. Among the single ML models, the Support Vector Machines model was found to be the most accurate in predicting subclinical mastitis at subsequent test-day when used both for the training set (mean F1-score of 0.760) and the testing sets containing data for herds 1, 2 and 3 (F1-score of 0.778, 0.790 and 0.741 respectively). The Gradient Boosting model was found to be the best performing model among the ensemble ML models (F1-score of 0.762, 0.779, 0.791 and 0.723 for the training set and the testing sets respectively). The super learner model, featuring the most advanced design and Logistic Regression in the meta layer, achieved the highest mean F1-score of 0.775 during the cross-validation, however, it was characterized by a slightly worse prediction accuracy of the testing sets (mean F1-score of 0.768, 0.790 and 0.693 for herds 1, 2 and 3 respectively). The study findings confirm the promising role of ensemble ML methods that were found to be slightly superior with respect to most of the single ML models.

Antimicrobial Activity of Selected Essential Oils against Staphylococcus aureus from Bovine Mastitis

Staphylococcus aureus is a major cause of subclinical mastitis in dairy cows, and its development of antibiotic resistance has limited treatment efficacy. Essential oils (EOs) are natural products with a wide range of antimicrobial properties that could be used to treat bovine mastitis. This study aims to investigate the antimicrobial activity of EOs against S. aureus isolated from subclinical bovine mastitis cases in the State of São Paulo—Brazil. A total of 14 S. aureus isolates were selected, based on the presence of biofilm-forming genes (icaA, icaD, and bap), and were cultured to a final concentration of 103 CFU.mL−1 for the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) analysis of five EOs (Citrus aurantium bergamia—bergamot, Copaifera reticulata—copaiba, Foeniculum vulgare—fennel, Zingiber officinale—ginger, and Ocimum basilicum—basil). The chemical compositions of the EOs were characterized using gas chromatography coupled with a mass-selective detector (GC/MSD). Basil and bergamot EOs exhibited the highest antimicrobial activity against S. aureus strains, with mean MIC/MBC values of 1.561 ± 0.223/2.806 ± 0.255 mg.mL−1 and 2.782 ± 0.228/4.396 ± 0.198 mg.mL−1, respectively. The primary compounds in basil EO were methyl-chavicol, linalool, and α-humulene, while bergamot EO predominantly contained linalyl acetate, limonene, and linalool. This research highlights the potential of basil and bergamot EOs as natural antimicrobial agents for treating bovine mastitis caused by S. aureus, offering a potential alternative to traditional antibiotics and contributing to animal welfare and public health. In addition, it emphasizes the need for further studies to validate the long-term effects, optimal dosages, and application methods.

Antibiotic Sensitivity of Pathogenic Bacteria Associated with Subclinical Mastitis of Dairy Cows in the Poro Region of the Ivory Cost

Antibiotic Sensitivity of Pathogenic Bacteria Associated with Subclinical Mastitis of Dairy Cows in the Poro Region of the Ivory Cost

Antibiotic Sensitivity of Pathogenic Bacteria Associated with Subclinical Mastitis of Dairy Cows in the Poro Region of the Ivory Cost

Subclinical mastitis is the most considered pathology in dairy farming and is responsible for economic losses in cows. The condition remains asymptomatic in dairy cows and treatment is mainly done without laboratory analysis. The objective of this work is to research bacterial causes of subclinical mastitis in dairy cows and to study their sensitivity to certain antibiotics. Thus, this study was carried out in four departments (Korhogo, Sinématiali, Dikodougou and M'bengué) in the Poro region (Ivory Coast) from May to August 2022 in traditional farms on 288 neighborhood milk samples taken from dairy cows with subclinical mastitis. The milk samples were analyzed using standard bacteriological isolation and identification techniques. Staphylococcus aureus were isolated on Baird-Parker potassium tellurite agar and mixed with egg yolk, Klebsiella spp isolated on MacConkey agar, Escherichia coli isolated on MacConkey, Pseudomonas aeruginosa isolated on TSA and King A agar, Micrococcus spp isolated on Chapman agar; then incubated at 37°C for 24 to 48 hours. The identification of bacteria was carried out by standard methods (appearance of colonies, Gram staining, catalase test, coagula-associated oxidase test, etc.). The biochemical characteristics were studied using the API Bio Mérieux galleries (API Staph and API20E etc.) The sensitivity of the main germs isolated was tested against ten (10) antimicrobials including those used in the treatment of mastitis by veterinary clinicians in the region. from Poro.The bacteriological analysis were identified 43% of Gram-positive cocci in minority, with particulary 18% of Staphylococcus aureus. In majority, Gram-negative bacilli were detected at 57% with particulary 38% of Enterobacteria (Klebsiella spp and Escherichia coli). The antibiogram showed excellent sensitivity to Staphylococcus aureus to Gentamycin 100%, good sensitivity to chloramphenicol and neomycin at 90% then acceptable sensitivity to the Trimethoprim-Sulfamethoxazole combination, to cefalexin of 80%. The coagulase negative staphylococcus (SCN) group revealed good sensitivity to Cefalexin and Gentamicin of (87.5%) and acceptable sensitivity to Chloramphenicol, Neomycin of (75%) each. On the other hand, Enterobacteria showed excellent resistance to Ampicillin, Spiramycin and Penicillin 100% and acceptable resistance to Gentamycin (95.84%). Remarkable resistance has been observed on the following antibiotics : Ampicillin, Penicillin and Colistin. This remarkable resistance was noted in Staphylococci (100% for Staphylococcus aureus and 87.5% for SCN) and Enterobacteria. Given these results, suggestions were made for the treatment and prevention of subclinical mastitis on farms in the Poro region (northern Ivory Coast).

Frequency of Some Important Exotoxin Genes in Pseudomonas aeruginosa Samples Isolated from Bovine Mastitis in Tabriz City in 2022

Background: Pseudomonas aeruginosa is an important opportunistic pathogen resulting in treatment-resistant subclinical mastitis in dairy cows. Examination of the frequency of some important virulence genes in isolates from bovine mastitis can be necessary for better management and recognition of infections caused by this bacterium. Objectives: This study was conducted on the frequency of some important exotoxin genes in P. aeruginosa samples derived from bovine mastitis in the city of Tabriz in 2022. Methods: This study was performed with 120 bacterial samples of P. aeruginosa that were isolated from clinical samples of bovine mastitis and were considered to investigate the frequency of some important exotoxin genes. Bacterial DNA was extracted, and the presence of exotoxin A, T, and U genes in P. aeruginosa samples was found by PCR method. Results: The frequency of exotoxin A, T, and U genes in P. aeruginosa samples was 18 (15%), 32 (26.6%), and 26 (21.6%), respectively, and 8 (6.6%) P. aeruginosa samples possessed all 3 intended genes simultaneously; while 76 (63.3%) P. aeruginosa samples lacked the tested genes. Conclusions: A relatively high frequency of exotoxin genes studied can be a serious warning to treat and control the bovine mastitis caused by this bacterium.

Status of subclinical mastitis in lactating cows of selected dairy farms in Bangladesh and farmers’ understanding of mastitis

Background: Subclinical mastitis, a disease that is economically important to dairy cows, affects milk production. Management of udder health is an essential element in the process of safe milk production. Consumption of milk with a high somatic cell count (SCC) may also pose a health risk to humans. Objectives. We aimed to evaluate the SCC method for the detection of SCM in dairy cows and to assess farmers’ knowledge, attitudes, and practices towards mastitis detection and control. Methods. A cross-sectional study was conducted to evaluate the current status of subclinical mastitis (SCM) in lactating dairy cows. The research work was also designed to assess farmers’ knowledge, attitudes, and practices about bovine mastitis. A total of 320 milk samples from 80 lactating cows were collected for physical examination and tested for subclinical mastitis using SCC. Results. Out of 80 lactating cows examined, 53 (66%, 95% CI: 55-76%) cows were diagnosed with subclinical mastitis. The average cow level SCC per ml of milk was 503101. According to the farmers’ self-report, 100% of farms practiced hand milking and 100% of milkmen washed their hands before milking. The majority of farms (90%) had brick floors. Most of the farmers (70%) knew about screening for subclinical mastitis. However, they never performed screening to detect subclinical mastitis. Conclusion. The high prevalence of SCM in dairy raised significant concerns about farm management, personal hygiene and biosecurity practices. Further study is needed to identify the etiologies of SCM and its associated risk factors.

Case-Control Study: Endogenous Procalcitonin and Protein Carbonylated Content as a Potential Biomarker of Subclinical Mastitis in Dairy Cows.

Procalcitonin (PCT) and protein carbonylated content (PCC) are promising biomarkers for bacterial infection and inflammation in veterinary medicine. This study examined plasma PCT and PCC levels in healthy cows (H) and cows with subclinical mastitis (SCM). A total of 130 cows (65 H and 65 SCM) were included in this study. Blood samples were collected, and plasma was frozen at -80 °C. PCT levels were determined using a bovine procalcitonin ELISA kit, while PCC was measured following the methodology of Levine et al. Statistical analysis revealed a significant difference in PCT levels between H (75.4 pg/mL) and SCM (107.3 pg/mL) cows (p < 0.001) and significantly lower concentrations of PCC in the SCM group (H: 0.102 nmol/mL/mg, SCM: 0.046 nmol/mL/mg; p < 0.001). The PCT cut-off value for distinguishing healthy and subclinical mastitis animals was >89.8 pg/mL (AUC 0.695), with a sensitivity of 66.2% and specificity of 69.2%. PCT showed potential value as a diagnostic tool to help in decision making for subclinical mastitis cases, while PCC requires further studies to investigate the trend of this biomarker during localized pathology.

162 Evaluating the Potential of a Thermal Imaging System to Identify Subclinical Mastitis in Dairy Cattle

Abstract The objective was to evaluate the potential for the use of a thermal imaging system for the identification of subclinical mastitis in dairy cows. Multiparous Holstein dairy cows (n = 131) within 150 days in milk (DIM; range 65 to 155) were enrolled in the study at a commercial dairy farm in central Texas. Milk samples (10 mL) were collected from each quarter separately and evaluated for somatic cell counts (SCC; n*1000), fat (%), protein (%), lactose (%), SNF (%), BHBA (mM/L), acetone (mM/L), and milk urea nitrogen (MUN; mg/dL). A minimum of four thermal images per cow representing all four quarters were captured using a handheld infrared camera (Fluke TiS 75+) from approximately one-meter distance from the cow. All images were taken inside the milking parlor and after the morning milking during February 2023 to minimize the impact of daily ambient temperatures. Skin temperatures from each quarter (maximum, minimum, average) were extracted using Fluke Connect software. A total of 524 quarter-level milk samples and corresponding udder images were obtained, and 10 images were discarded from analyses due to the lack of appropriate resolution and focus. To prevent collinearity, a correlation matrix was developed using PROC CORR in SAS and variables with significant correlations were removed from the model. Subclinical mastitis was defined at the quarter level when SCC &amp;gt; 250,000. Statistical analyses were performed using mixed linear regression models (PROC MIXED) with cow and DIM as random effects in the model, and logistic regression model (PROC LOGISTIC) was fitted to evaluate the probability of the disease based on temperature and milk variables. Maximum and average udder temperatures did not demonstrate a significant relationship with subclinical mastitis status whereas minimum udder temperature was greater in sick quarters (29.6 ± 0.52 vs 27.5 ± 0.45; P = 0.003). Increased minimum udder temperature was also associated with BHBA (P &amp;lt; 0.0001), acetone (P &amp;lt; 0.0004), and MUN (P &amp;lt; 0.0007) concentrations in milk. Cows with subclinical mastitis had decreased BHBA (0.14 ± 0.037 vs 0.28 ± 0.031; P = 0.0036) and acetone (0.017 ± 0.003 vs 0.044 ± 0.003; P &amp;lt; 0.001). Odds of subclinical mastitis were associated with MUN values in milk (OR 0.94; CI 0.89 - 0.98) but not with any udder surface temperature variables. We conclude that an increase in the minimum temperature of the udder could be used as an indicator of subclinical mastitis but studies with larger datasets and using advanced image analysis techniques are warranted to validate these results.

Ozone use in the treatment of subclinical mastitis in dairy cows.

This research communication paper addresses the hypothesis that the use of therapeutic alternatives for mastitis, such as intramammary ozone, can cure the disease with lower costs and without harmful residues for human consumption and without formation of microbial resistance like the ones caused by indiscriminate use of antibiotics in dairy farms. The study was performed in 36 mammary quarters from 12 dairy cows with subclinical mastitis grade three. The experimental units were randomly assigned into four groups and each group received a treatment. Treatments comprised (a) 20 μg/ml ozone gas; (b) 40 μg/ml ozone gas; (c) negative control treatment of 12.5 μg/ml ozonated saline and (d) positive control treatment of 100 mg of cephalexin + 100 mg of neomycin + 10 mg of prednisolone, all by intramammary injection. In all quarters, milk was collected before and after the application of treatments for California mastitis test and evaluation of milk composition, somatic cell count, and bacterial cultures. The results indicated that the use of intramammary ozone did have a therapeutic effect, and whilst this was less than that of antibiotics, ozone does confer some advantages. Treated milk had a good composition, the treatment cost was low, milk withdrawal may not be necessary and there is no risk of antibiotic resistance.

Streptococcus Spp. Isolated Subclinical Mastitis and Its Effect on Public Health

The high protein content of milk makes it a crucial component of human nutrition. The mammary tissue of dairy cattle is seriously harmed by the severe disease known as mastitis. Mastitis is a widespread and economically significant infectious disease that affects dairy cows globally. One of the most frequent causes of subclinical mastitis in dairy cows and one of the most frequent indications for antibiotic therapy is Streptococcus spp. The purpose of the study was to investigate into the presence of Streptococcus spp. isolates in subclinical mastitis bovine milk. The presence of subclinical mastitis was investigated in 77 dairy animals. After the evaluation, 32 (41.5%) dairy animals showed positive results. Streptococcus spp. was detected in nine isolates (19.50%). As a result, it has been demonstrated that Streptococcus spp. still plays a significant role in the etiology of subclinical mastitis. This has the potential to present an important concern for public health.

Detection of Methicillin-resistant Staphylococcus aureus (MRSA) resistant to vancomycin and linezolid in bulk tank milk by E-test method

Staphylococcus aureus is considered a serious threat to public health, besides is one of the most common causes of subclinical mastitis in dairy cows. Therefore, especially methicillin-resistant Staphylococcus aureus (MRSA) is among the most critical reasons for antibiotic treatment. Monitoring the antibiotic resistance of MRSA from livestock animals and foods is of great significance. The E-test method is a suitable option for detecting antibiotics' minimum inhibition concentration (MIC) value because it is an easy and fast assay to perform. This study aimed to detect vancomycin, teicoplanin, and linezolid resistance of milk-borne 34 MRSA isolates with subclinical mastitis by the E-test method to determine MIC values. The study determined that 8.8% of MRSA isolates isolated from milk with subclinical mastitis were also resistant to vancomycin and 11.7% to linezolid, while none of the isolates were determined to be resistant to teicoplanin, according to EUCAST. The data obtained from the study reveal that the efficacy of vancomycin and linezolid antibiotics, which are commonly used against MRSA infections, are in danger. Especially before MRSA treatment, MIC values of antibiotics should be determined, and appropriate antibiotics should be used in effective doses.

Comparative Analysis of Methods for Somatic Cell Counting in Cow's Milk and Relationship between Somatic Cell Count and Occurrence of Intramammary Bacteria.

The aim of this study was to compare three on-farm commercial methods for the indirect detection of subclinical mastitis in dairy cows: the California mastitis test (CMT), the Porta side somatic cell count milk test (Porta SCC), and the DeLaval cell counter (DCC), with the Fossomatic cell count (FSCC), and to evaluate the relationship between the determined somatic cell count SCC and the occurrence of intramammary pathogens in the milk of dairy cows. A total of 284 sensory unchanged mixed milk samples, collected during the milking on a dairy farm, were analyzed in this study for somatic cell counts by the mentioned on-farm tests. Quarter milk samples (n = 583) from all the selected cows were cultured. The agreement, sensitivity, and specificity of the three indirect commercial diagnostic tests (the CMT, the Porta SCC, and the DeLaval cell counter) were calculated, and the FSCC was used as the gold standard. The results were analyzed statistically using the Pearson correlation test and the paired t-test. The CMT matched with the FSCC in 83.1% of the samples, with the Porta SCC in 80.6%, and with the DCC in 80.3% of the samples. The sensitivity and specificity reached 81.0% and 92.9% for the CMT, 79.4% and 90.7% for the Porta SCC, and 75.8% and 97.5% for the DCC, respectively. The correlation between the FSCC and the Porta SCC was 0.86 (p < 0.0001), and between the FSCC and the DCC, it was 0.92 (p < 0.0001). The differences between them were insignificant. Bacteria were detected in 130 (22.3%) quarter milk samples. The most prevalent bacteria were Enterococcus spp. (36.2%), followed by E. coli (20%), coagulase-negative staphylococci (13.1%), A. viridans (9.2%), Streptococcus spp. (9.2%), Proteus spp. (6.2%), and S. intermedius (3.9%). Contagious isolates (S. aureus) were detected in 3 quarter milk samples (2.3%). The agreement between the individual tests and the microbiological culture was as follows: 69.2% for the CMT; 73.7% for the Porta SCC; 71.6% for the DCC; and 76.5% for the FSCC. Higher SCCs were detected in the milk samples contaminated with bacteria than in the healthy milk (p < 0.001). No significance was found between the presence of individual species of intramammary pathogens and the different levels of SCCs. Based on the results, bacteria are the predominant cause of subclinical mastitis. The increased SCC of some milk samples with no presence of bacteria meant that the increase could have been caused by numerous other agents (viruses, fungi, or algae) or factors for mastitis in the dairy industry.

Seasonal, physiological and bacteriological risk factors for subclinical mastitis in dairy cows maintained under different farming conditions.

Subclinical mastitis (SCM) is a major health problem of dairy animals in India and across the globe. An identification of potential risk factors of SCM can help for efficient udder health management in dairy animals. In this study, apparently healthy cows (HF crossbred: n = 45; Deoni: n = 43) were screened for SCM during different seasons through milk somatic cell count (SCC: reference test using 200 × 103 cells/ml as cut off value), California mastitis test (CMT) and differential electrical conductivity (DEC) test at an organized research farm. SCM positive milk samples (n = 34) were inoculated in selective media for Coliform sp., Streptococcus sp. and Staphylococcus sp. and DNA was isolated (n = 10) for species confirmation by 16s rRNA method. Both bivariate and multivariate models were used for risk assessment. We found the cumulative prevalence of 31 and 65% SCM in Deoni and crossbred cows, respectively. Screening of 328 crossbred cows under field conditions revealed point prevalence of 55% SCM. Multivariate analysis revealed stage of lactation (SOL), milk yield in previous lactation and test day milk yield in Deoni cows, as well as parity and mastitis treatment history in current lactation in HF crossbred cows as risk factors. SOL was a significant factor under field conditions. Receiver operated characteristic curve analysis revealed better accuracy of CMT than DEC. We found more mixed infections due to Staphylococcus sp. and Streptococcus sp. in culture, while 16s rRNA based molecular method revealed lesser-known pathogens associated with SCM. It is concluded that SCM prevalence rate is higher in crossbred than indigenous cows and these breeds have different risk factors for SCM. HF crossbred cows had similar SCM prevalence rate under different farming conditions, where CMT can be used for SCM diagnosis with excellent accuracy. The 16s rRNA method is useful for specific identification of lesser known and emerging mastitis pathogens.

Antimicrobial Resistance Profile and Molecular Characterization of Staphylococcus aureus Isolated from Subclinical Mastitis of Dairy Cows in Mathura Region

Background: Subclinical mastitis is the most underrated yet economically important disease of livestock. It goes undetected by clinical examinations, making routine surveillance and monitoring necessary for its detection. Among causative agents, Staphylococcus aureus is the most crucial one. The present study determines the prevalence, antimicrobial resistance profile and molecular characterization of S. aureus from subclinical mastitis of cattle in the Mathura region. Methods: The present research was conducted during 2019-2021 and different gaushalas and dairies in and around the Mathura region were screened for mastitis by California mastitis test and somatic cell count. The samples positive were further tested by bacterial, biochemical and molecular tests along with an antimicrobial resistance profile. Result: Our research found a significant amount of S. aureus in subclinical samples with the presence of mecA gene suggesting MRSA. The public health importance of S. aureus and emerging resistance against antibiotics demands regular monitoring and effective use of antimicrobial agents against the MRSA isolates.

Molecular detection of Stx1 and Stx2 genes of E. coli isolated from sub-clinical bovine mastitis in Mosul city

Subclinical mastitis in cattle is a pathological condition that causes a financial burden on the dairy industry. In addition, it puts the public sector at risk when pathogens of animal origin are present in unpasteurized milk and dairy products that may enter the human food chain and cause serious illnesses. Our study aimed to determine the percentage of pathogenic Escherichia coli causing subclinical mastitis in dairy cows in Mosul city by confirming the existence of Stx1 and Stx2 genes. Eighty milk samples were obtained from cows suffering from subclinical mastitis using sterile procedures from November 2018 to October 2019. Escherichia coli was isolated, characterized, and confirmed using culture and PCR. According to our research, the pathogenic Escherichia coli in milk samples was 36.3% (29/80). Moreover, molecular screening for a specific Escherichia coli gene revealed that all isolates 100% carried the uidA gene. PCR revealed that 27/29 (93.1%) isolates had both Stx1 + Stx2 genes, and all the isolates 100% possessed the Stx2 gene. No significant relationship was found between the percentage of pathogenic E. coli and the seasons. Even though there were more isolates in the winter than in the summer, this increase was not statistically significant. This study's findings may help pay attention to one of the leading causes of subclinical mastitis, which benefits the private sector in controlling the disease.

An Evaluation of Draminski Detector as an Early Detection Tool for Subclinical Mastitis in Dairy Cattle in Pondok Ranggon Farm

Subclinical mastitis is one of the main problems in the development of dairy farming in Indonesia. Several screening test tools have been developed to support of control program for this problem. This study aimed to assess the suitability of the Draminski detector as a screening tool for subclinical mastitis in dairy cows. Quaternary milk samples from 27 dairy cows during normal lactation in the Pondok Ranggon area, East Jakarta were collected to be evaluated for the possibility of coming from quarters suffering from subclinical mastitis. Each milk sample was tested with 3 types of tests, i.e. the Breed method (golden standard) which was based on the number of somatic cells, the device Milkchecker which was based on electrical conductivity, and the Draminski detector which was based on electrical resistance. The results showed that the Draminski detector had a poor level of compatibility with the Breed method as the golden standard (Kappa value 0,013) and the Milkchecker tool (Kappa value 0,036). This test method was also considered to have poor test performance in diagnosing cases of subclinical mastitis in dairy cattle with a sensitivity value of 3,5%, specificity 100%, positive predictive value 100%, negative predictive value 18,8%, estimated prevalence 2,9%, and the true prevalence was 81,7%. In conclusion, the Draminski detector cannot be used to replace the Breed method and Milkchchecker as a screening test tool in cases of subclinical mastitis in dairy farms in Indonesia which were generally reared in the dairy farms.

Clinical field trial of parenteral amoxicillin for the treatment of clinical and subclinical mastitis in smallholder dairy farms in the upper region of Northern Thailand.

Mastitis, primarily caused by intramammary bacterial infection, is the most expensive disease in the global dairy industry due to its negative impact on milk composition and manufacturing properties. This study aimed to evaluate the efficacy of parenteral amoxicillin in the treatment of clinical and subclinical mastitis in smallholder dairy farms in Northern Thailand. A total of 51 cows with clinical and subclinical mastitis from dairy cooperatives in Lamphun and Chiang Mai provinces, Northern Thailand, were enrolled in this study. Conventional bacteriological procedures were applied to identify the causative bacteria in milk samples from these cows before and 7 days after treatment, and antibiotic susceptibility tests were conducted using the disk diffusion method for all bacteria isolated before treatment. All cows with mastitis were administered 15 mg/kg of amoxicillin (LONGAMOX®, Syva Laboratories SA, Spain) intramuscularly every other day for 3 days. Environmental streptococcal bacteria (Streptococcus uberis and Streptococcus spp.) were commonly isolated from infected quarters and were highly susceptible to amoxicillin (100%). The clinical efficacy of amoxicillin treatment for clinical mastitis cases was 80.43%, and the bacteriological efficacy was 47.82%, with opportunistic staphylococcal bacteria (coagulase-negative staphylococci) and contagious streptococcal bacteria (Streptococcus agalactiae) being the most sensitive microorganisms (100%). In subclinical mastitis cases, the bacteriological efficacy of parenteral amoxicillin was 70.45%, with environmental streptococcal bacteria (S. uberis) being the most (100%) sensitive microorganisms. Amoxicillin is highly efficacious and can be used to treat clinical and subclinical mastitis in dairy cows, particularly mastitis caused by environmental Streptococcus spp. These findings could be used to guide treatment regimens in veterinary practice in smallholder dairy farms in Thailand.

Protein Expression Profiles in Exosomes of Bovine Mammary Epithelial Cell Line MAC-T Infected with Staphylococcus aureus.

Mastitis is a common and widespread infectious disease in dairy farms around the world, resulting in reduced milk production and quality. Staphylococcus aureus is one of the main pathogenic bacteria causing subclinical mastitis in dairy cows. S. aureus can activate inflammatory signaling pathways in bovine mammary epithelial cells. Exosomes produced by cells can directly transfer pathogen-related molecules from cell to cell, thus affecting the process of infection. Protein is the material basis of the immune defense function in the body; therefore, a comprehensive comparison of proteins in exosomes derived from S. aureus-infected (SA group) and normal (control group [C group]) bovine mammary epithelial MAC-T cells was performed using shotgun proteomics by a DIA approach. A total of 7,070 proteins were identified and quantified. Compared with the C group, there were 802 differentially expressed proteins (DEPs) identified in the SA group (absolute log2 fold change [|log2FC|] of ≥0.58; false discovery rate [FDR] of <0.05), among which 325 proteins were upregulated and 477 were downregulated. The upregulated proteins, including complement 3 (C3), integrin alpha-6 (ITGA6), apolipoprotein A1 (APOA1), annexin A2 (ANXA2), tripeptidyl peptidase II (TPP2), keratin 8 (KRT8), and recombinant desmoyokin (AHNAK), are involved mostly in host defense against pathogens, inflammation, and cell structure maintenance. KEGG enrichment analysis indicated that DEPs in S. aureus infection were involved in the complement and coagulation cascade, phagosome, extracellular matrix (ECM)-receptor interaction, and focal adhesion pathways. The results of this study provide novel information about proteins in the exosomes of MAC-T cells infected with S. aureus and could contribute to an understanding of the infectious mechanism of bovine mastitis. IMPORTANCE Mastitis is a widespread infectious disease in dairy farms, resulting in reduced milk production and quality. Staphylococcus aureus is one of the main pathogenic bacteria causing subclinical mastitis. Exosomes contain proteins, lipids, and nucleic acids, which are involved in many physiological and pathological functions. The expression of proteins in exosomes derived from bovine mammary epithelial cells infected by S. aureus is still barely understood. These results provide novel information about MAC-T-derived exosomal proteins, reveal insights into their functions, and lay a foundation for further studying the biological function of exosomes during the inflammatory response.

Meta-analysis and meta-regression of subclinical mastitis prevalences of dairy cattle in Turkey

Mastitis is one of the most important problems of the dairy industry because of the economic losses due to decreases in milk yield and in milk quality. Subclinical mastitis is a form of mastitis that has no macroscopic inflammation in the mammary gland and visible change in milk, and approximately 70-80% of milk losses caused by mastitis are due to subclinical mastitis. Many previous studies, screening the mastitis and the isolation and identification of microorganisms in collected milk samples, have been conducted in dairy cattle at the regional level in Turkey. Since many studies have been performed to predict the prevalence of subclinical mastitis and to determine the factors affecting the disease, systematic review or meta-analysis studies on the subject have been required. &#x0D; In this study, it was aimed to determine the prevalence of subclinical mastitis obtained from 38 studies conducted in Turkey between 1988 and 2019 by meta-analysis method and to calculate common prevalence. The estimated prevalence of subclinical mastitis in the studies were evaluated separately as cow-based (11182 cows in 37 studies) and udder quarter-based (48990 udder quarters in 33 studies). According to the results, the common prevalence of subclinical mastitis was calculated as 0.49 (95% CI: 0.41-0.56) in cow-based studies and 0.32 (95% CI: 0.26-0.37) in quarter based-&#x0D; based studies. As a result of this study, the results of individual studies on the prevalence of subclinical mastitis in dairy cows in Turkey were combined with the meta-analysis method and a more precise estimate of the prevalence was obtained.