California Mastitis Test Score Research Articles

Therapeutic Efficacy of Eucalyptus Oil as Teat Dip in Subclinical Mastitis in Goats

Mastitis, an inflammation of the parenchyma of mammary gland, results in alterations to the chemical and physical composition of milk due to a variety of infectious and non-infectious causes. The present work was conducted in the Department of Veterinary Medicine, College of Veterinary Science and Animal Husbandry, Nanaji Deshmukh Veterinary Science University, Jabalpur, Madhya Pradesh (M.P.). A total of 256 lactating goats irrespective of age, breed, parity and stage of lactation belonging to both organized and unorganized sectors at Jabalpur were screened from “February 2024 to July 2024”. On the basis of modified California mastitis test (MCMT) score, out of 256 lactating goats, 98 goats were found positive for subclinical mastitis with overall occurrence as 38.28% on animal basis and 33.33% on udder halves basis. Therapeutic study on 24 milk samples positive for subclinical mastitis by MCMT was conducted and categorized into four treatment groups (G1, G2, G3 and G4), each group comprised of 6 goats. Six apparently healthy goats were selected as healthy control group (G5). Two different teat dips viz. Eucalyptus oil 98% + DMSO 2% BID for 14 days in groups G1 and G3 and 5% Povidone iodine BID for 14 days in groups G2 and G4 were used as teat dips, respectively. Moreover, goats of groups G3 and G4 were commonly treated with parenteral antibiotic amoxicillin sulbactam @10 mg/kg b.wt. I/M OD for 3 days. Significantly higher values of somatic cell count, standard plate count, pH, freezing point and significantly lower value of lactose were observed in subclinical mastitis affected goats. The mean density and mean water percentage values varied within normal physiological range. On the basis of restoration of milk parameters and standard plate count, the most effective therapy was elicited by Eucalyptus oil 98%+ DMSO 2% as teat dip in combination with antibiotic amoxicillin sulbactam (G3).

Comparative Evaluation of Antibiotic Therapies for Subclinical Staphylococcal Mastitis in Goats

Subclinical mastitis (SCM) is characterized by inflammation of the udder without visible signs of inflammation in the animal, udder and milk and hence could be diagnosed by laboratory examination only. Effective treatment of SCM in goats is crucial for maintaining quality milk production. This study was conducted at the Department of Veterinary Medicine, College of Veterinary Science and Animal Husbandry, Nanaji Deshmukh Veterinary Science University, Jabalpur (M.P.), India. A total of 236 lactating goats irrespective of age, breed, parity and stage of lactation, from both organized and unorganized sectors in and around Jabalpur, were screened over a period of six month. Based on modified California mastitis test scores, 83 goats tested positive for subclinical mastitis resulting in an overall occurrence of 35.17% (83/236). A total of 48 milk samples that tested positive for modified California mastitis test were further analyzed for bacterial isolation and identification. Among them, 34 (70.83%) samples were positive for only Staphylococcus spp., while 12 (25%) samples exhibited mixed infection with Staphylococcus spp. and Gram-positive bacilli. Then, 18 goats, positive for subclinical Staphylococcal mastitis were divided into three groups i.e. G1, G2 and G3 with six goats in each group for therapeutic study and six apparently healthy goats were taken as healthy control group (G4). G1 Goats were treated with Inj. Enrofloxacin LA @ 7.5 mg/kg b. wt. I/M single dose; G2 with Inj. Ceftizoxime @ 10 mg/kg b. wt. I/V single dose and G3 with Inj. Oxytetracycline LA @ 20 mg/kg b. wt. I/M single dose. The responses of therapeutic assessment were evaluated on the basis of somatic cell count and modified California mastitis test score. The most effective response for subclinical Staphylococcal mastitis in goats was observed with Ceftizoxime followed by Enrofloxacin LA and the least with Oxytetracycline LA.

Comparative prevalence assessment of subclinical mastitis in two crossbred dairy cow herds using the California mastitis test

The study was conducted on two herds of Jersey crossbred dairy cows. Samples were taken from two dairy farms to conduct the California Mastitis Test (CMT) during milking. A total of 115 animals were sampled, with 65 animals from Farm 1 and 60 animals from Farm 2. Milk samples were collected from all four quarters of each cow. The study analyzed a total of 460 quarters from the collected milk samples. Among these quarters, 132 quarters (28.69%) were found to be infected. The prevalence of mastitis was 45% in Herd 1 and 25% in Herd 2. The study found that only one quarter of the udder was more affected in both herds. The CMT score (likely a measure of mastitis severity) increased during late lactation. Infected cows had an average milk yield/day of 3.6 liters. Inflammatory (within or under the mammary gland) infections were more common in the first and second parity cows (cows that had given birth to one or two calves, respectively). This could be ascribed to the fact that dairy cows in their starting lactations are more vulnerable to the environmental pathogens because they might not have built up their immunity yet. Overall, this study provides insights into the prevalence, severity, and patterns of mastitis in Jersey crossbred dairy cows located at two different farms. The study highlights factors such as the stage of lactation, parity, and herd differences that can influence the occurrence and severity of mastitis in these animals.

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.

Udder thermogram-based deep learning approach for mastitis detection in Murrah buffaloes

Mastitis, a production disease with multiple etiologies, inflicts significant economic losses among dairy farmers around the globe. In this study, an attempt has been made to detect mastitis through a Convolutional Neural Networks (CNN)-based deep learning model using 7615 udder thermograms of 40 Murrah buffaloes. The thermograms were grouped separately as healthy, sub-clinical (SCM), and clinical mastitis (CM) affected udder quarters based on California Mastitis Test (CMT) scores, Somatic Cell Count (SCC) values and thermal image analysis. Results of thermogram analysis revealed a significant increase (p < 0.01) in the mean values of udder skin surface temperature (USST) among SCM and CM-affected quarters compared to healthy quarters to the tune of 1.32 and 2.61 °C, respectively. The USST showed a strong positive correlation with the CMT score (r = 0.87, p < 0.01) and log10SCC value (r = 0.88, p < 0.01). The sequential (Normal vs. Clinical and Normal vs. Sub-clinical) models had training accuracy and validation accuracy of 0.999 and 0.988, 0.991 and 0.978, respectively. The confusion matrix for Normal vs. Clinical and Normal vs. Sub-clinical models reflected a loss of 0.009 and 0.029, precision of 0.947 and 0.980, and recall of 0.996 and 0.904, respectively. Consequently, the sequential (Normal vs. Clinical and Normal vs. Sub-clinical) models achieved a testing accuracy of 0.970 and 0.943, respectively. Thus, the improved deep-learning CNN models efficiently predicted SCM and CM cases in Murrah buffaloes.

Antibiograms, multidrug resistance, and milk-related parameters of bacteria isolated from milk of dairy cattle in Phatthalung, Thailand.

Milk, a nutritious food, is widely consumed in human diets; however, contamination by micro-organisms can negatively impact its quality and consumer health. Contamination by micro-organisms affects the quality of milk, which can affect the quality of the milk production chain. This study aimed to determine the changes in milk composition and antibiotic susceptibility related to bacteria isolated from dairy cow milk. Raw milk samples were collected from 72 dairy cows. All milk samples were subjected to the California Mastitis Test (CMT) for CMT score determination. We also investigated milk composition, bacterial culture (BC), and antibiotic susceptibility. About 47.22% and 30.56% of dairy cattle were positive for CMT + BC and automatic somatic cell count (ASCC) + BC, respectively. Fecal appearance and animal age were found to be risk factors for ASCC + BC positivity in dairy cattle. Bacteria were found in approximately 76% of milk samples, with the most common isolated species being α-hemolytic Streptococcus spp., coagulase-negative Staphylococcus spp., and Escherichia coli. Of these, 70% are resistant to at least one antibiotic. Variation in the multidrug resistance pattern was high in Klebsiella spp. Fecal appearance and animal age are risk factors for ASCC + BC positivity in dairy cattle. This study identified antibiotic and multidrug resistance patterns, which require comprehensive studies and effective surveillance systems. Remarkably, the use of antibiotic therapy in dairy cattle should be monitored.

COMPARISON OF CULTIVATION TESTS TO DETECTION MASTITIS IN DAIRY COWS

Mastitis is an inflammation of the mammary gland which has a particular importance in ruminants. The purpose of this study was to evaluate and compare two methods for cultivation of udder pathogens: classical laboratory cultivation on Columbia agar with 5% sheep blood versus MicroMast rapid plates. The results allowed assessing the incidence of mastitis and the prevalence of the pathogens. During the study have been investigated 227 cows in a dairy farm localized in the east of Slovakia. Subsequently, 141 quarter milk samples from the positive cows with California mastitis test score 1-4 have been undergone the laboratory culture on Columbia agar and MicroMast test in accordance with their respective steps. The values obtained from these tests showing sensitivity of positive samples using the MicroMast test at the level of 64.5%, and sensitivity of cultures on Columbia blood agar at the level of 61.7%. After biochemical identification of cultured isolates, the Columbia blood agar and MicroMast test identified both as the main pathogen present Staphylococcus aureus (S. aureus) with results of 13.4% and 14.9%, respectively. On the base of results, both tests are comparable and therefore a test that speeds up testing is more useful in practice. It will be a relevant importance in the following decades to succeed in the development of tests with directly detection of udder pathogens.

Anadolu mandalarının subklinik mastitis vakalarında CMT, SCC ve Bakteriyolojik izolasyon örtüşüyor mu? Özet

Abstract&#x0D; Subclinical mastitis is the most important and costly disease in the dairy sector. In this study, it was aimed to compare the results of bacteriological examination with those of California Mastitis Test (CMT) and Somatic Cell Count (SCC)in the milk samples collected from Anatolian buffaloes with no clinical signs of mastitis. For this purpose, 96 milk samples were collected from 24 Anatolian buffaloes of each quarter. All milk samples were examined for the presence of mastitic pathogens by bacteriology regardless of SCC values and CMT scores. A total of 103 isolates were recovered from the infected quarters. The first three frequently isolated mastitic pathogens were determined to be E. coli, S. agalactiae, and S. aureus with the rate of 31.07%, 22.33%, and 21.36%, respectively. According to the bacteriology results, threshold value for SCC was accepted as ≥78.000 cells/ml. The correlation value between CMT and SCC, CMT and bacteriology, and SCC and bacteriology was found as 0.737, 0.845 and 0.872, respectively, and the mean of inter-item correlation was determined 0.818. These results showed that the test results were highly correlated with each other. The results of the ROC analysis of the cut-of-value of the SCC test for this study chosen as 78.000 cells/ml supported the results obtained from the reliability analysis with sensitivity 85% and 1-specifity 100%. To sum up, a combination of CMT, SCC, and bacteriological investigation provides benefits in detecting mastitis early and avoiding misdiagnosis, allowing for timely action and treatment.&#x0D; Keywords: Anatolian Buffalo, CMT, SCC, bacteriology

Assessment of milk and blood enzymes in Holstein cows with subclinical mastitis

The objective of this study was to determine the activities of lactate dehydrogenase (LDH), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the milk and blood of lactating Holstein cows and investigate their association with subclinical mastitis (SCM). This study also aims to evaluate the impact of SCM and its severity based on California mastitis test (CMT) scores on the above mentioned enzymes, as well as to test the efficiency of their use as an early predictive diagnostic tool. Thirty multiparous, lactating dairy Holstein cows were examined using CMT and according to the obtained results classified into four groups; control group 1 (SCM-free = 10, score = 0), group 2 (weak positive = 8, score +1), group 3 (positive = 7, score +2) and group 4 (strong positive = 5, score +3). The milk LDH, ALP, and GGT activities were significantly higher in groups 3 and 4 compared to group 2 and the control group. LDH activity was significantly higher in group 2 compared to the control group. The mean blood LDH and ALP activities in SCM groups were significantly higher than in the control group. ALP blood activity was significantly higher in group 4 compared to group 2. The blood GGT activity was significantly higher in group 4 compared to other groups. There was a significant positive association between milk LDH, ALP, and GGT enzymes as well as the blood enzymes (ALP and GGT) in SCM cows. The results showed that subclinical mastitis causes considerable changes in the activities of enzymes in milk and blood of infected cows.

The influence of subclinical mastitis on the protein composition and protease activities of raw milk from lactating Thai-crossbred dairy cows.

Mastitis in dairy cattle is associated with a high rate of morbidity and death, which has major implications for milk production and quality. This study aimed to investigate the protein component and the activity of matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) in raw milk samples with different testing scores determined using the California mastitis test (CMT). Thirty cows were employed in the study, and milk from each quarter was tested for subclinical mastitis (SCM). According to the results of CMT, raw milk samples were classified into five categories: Healthy (score 0), trace (score T), weakly positive (score 1), distinctly positive (score 2), and strongly positive (score 3) for somatic cell count (SCC). The total milk protein was analyzed using the Bio-Rad protein assay, and the milk protein composition was determined using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis technique. In addition, gelatin zymography was used to evaluate changes in proteolytic abilities. Milk samples with CMT scores of 1 and 3 had the highest total milk protein levels (32.25 ± 12.60 g/L and 32.50 ± 7.67 g/L, respectively), while the samples from healthy cows (CMT score 0) were only 6.75 ± 1.64 g/L. Globulin and lactoferrin were significantly increased in samples with a CMT score of 3 compared with those with other CMT scores. The bovine serum albumin level in samples with a CMT score of 2 was significantly (p < 0.05) higher than those with other CMT scores. No significant differences in casein abundance were found among samples with different CMT scores. Results from analysis of proteolytic activities demonstrated that the level of MMP-9 in samples with a CMT score of 3 was significantly (p < 0.05) higher than those with other CMT scores. The protein content and gelatinolytic activity of milk were drastically altered by the number of SCC, mainly due to SCM.

The prevalence and risk factors of subclinical mastitis in water buffalo (Bubalis bubalis) in Bangladesh

Subclinical mastitis (SCM) in water buffalo is responsible for reduced milk yield and quality. This cross-sectional study was carried out to a) estimate the prevalence of SCM, b) identify risk factors associated with SCM, and c) identify farm-level risk factors associated with bulk milk somatic cell count (BMSCC).The buffalo farms included in this study represented five rearing systems: free-range, semi-free-range, household, semi-intensive, and intensive, providing a total of 3491 functional quarters of 880 lactating buffalo on 248 farms. The California mastitis test score was used to identify SCM. Bulk milk samples (n = 242) were used for farm-level BMSCC. Quarter and buffalo-level risk factors for SCM were measured using questionnaires and observations.The overall SCM prevalence was high at 27.9% at the quarter-level (25th and 75th percentiles: 8.3% and 41.7%) and 51.5% at buffalo-level (25th and 75th percentiles: 33.3% and 66.7%). The geometric mean BMSCC was 217,000 cells/mL of milk (ranging from 36,000-1,213,000 cells/mL), which is low on average, but some farms could improve substantially. The buffalo rearing system, udder location (left versus right), teat shape, udder asymmetry, number of milkers, and having a quarantine facility were associated with buffalo udder health. Our findings suggest that mainly using free-range rearing systems may help decrease the prevalence of SCM primarily by employing buffalo breeding and better farm biosecurity, and udder health control strategies can be designed based on our findings.

Association between differential somatic cell count and California Mastitis Test results in Holstein cattle

The California Mastitis Test (CMT) has been used to estimate total somatic cell count (SCC) levels in milk; however, milk with similar SCC levels occasionally shows inconsistent CMT results, which limits the use of the CMT. This observational study aimed to investigate how differential cell counts in milk influence the CMT in Holstein cattle through the novel parameters differential somatic cell count (DSCC) and macrophage proportion (MAC). We performed the CMT on d 0, 3, 5, 7, 14, and 21 after identifying mastitis, and simultaneously measured SCC, DSCC, and MAC at the quarter level. We followed 58 mastitis events occurring in 41 cows and obtained 307 quarter-level records after data cleaning. We transformed SCC to somatic cell score (SCS) and MAC to its logarithm to fit the normal distribution and analyzed the data using the cumulative logit mixed model. Results showed that both an increase in SCS (odds ratio: 3.66, 95% confidence interval: 2.89–4.64) and the logarithm of MAC (odds ratio: 4.35, 95% confidence interval: 1.91–9.91) can contribute to a higher CMT score. During the healing process of mastitis, MAC tends to increase as SCC decreases; thus, even samples with low SCC can cause positive CMT reactions. We recommend that practitioners avoid making treatment decisions based on the CMT alone. We also noted that the CMT is sensitive to subclinical mastitis with high MAC, hence it could be considered an alternative to detecting high MAC (chronic) mastitis.

Use of a nonlinear model to estimate milk losses due to subclinical mastitis in Holstein-Zebu cows.

The objective of this observational study was to estimate milk loss from subclinical mastitis (SCM) using a nonlinear one-phase exponential decay function fitted to the relationship between the sum of the California mastitis test scores of productive quarters (x1, 0 to 16) and daily milk production per cow (y, kg/day). The function was y = (a - b)e-c1*x1 + b, where a is the predicted y when x is zero, b is the y when x1 tends to infinity, and c1 is a rate constant. The fitted function was y = (10.02 - 5.76)e-0.06137*x1 + 5.76, with an adjusted coefficient of determination (R2adj) of 0.0692, a standard deviation of the residual (Sy.x) equal to 13.49, and an Akaike's information criterion corrected (AICC) of 3902.8. To this function, we added the multiplicative factors test day (x2, 1 to 12), the number of productive quarters (x3, 2, 3 or 4), months of age of cow (x4, 25 to 209), and days in milk (x5, 2 to 196), to adjust the decay function for their effects. The fitted model was y = [(9.65 - 3.95)e-0.03415*x1 + 3.95] (x2-0.1081) (x30.1049) (x40.1589) (x5-0.1972) with R2 of 0.3166, Sy.x = 11.38, and AICC = 3821.9. We used the adjusted decay function parameters to compute a conversion factor (CF, 0 to 1) each x1 integer value from 0 to 16 to project its actual y to that of an SCM-free udder (x = 0). Then, the CF for a x1 of 0 equals to 9.65/9.65 = 1, and for a x1 of 8 equals 8.28, so its CF would be 8.29/9.65 = 0.8588. A cow with a 5.5kg/day milk production at an x1 score of 8 would have an SCM-free production of 5.5/0.8588 = 6.4kg/day, and its daily milk loss would be 6.4-5.5 = 0.9kg/day. The difference, multiplied by MX$ 5.50 (US$ 0.275), would result in an economic loss of 4.95 Mexican pesos per day. This procedure makes possible the timely on-site estimation of economic losses due to subclinical mastitis.

Evaluation of Usefulness of Infrared Thermography for the Detection of Mastitis Based on Teat Skin Surface Temperatures in Dairy Cows

Given the severe economic losses due to mastitis, the identification of a diagnostic tool that can rapidly screen cows suspected of mastitis immediately before milking would be especially advantageous for farmers owning a large number of dairy cows. It is important to detect mastitis at an early stage to ensure effective and successful prevention and management of intramammary infections. Therefore, this study evaluated utility of Infrared Thermography (IRT) as a diagnostic tool for mastitis based on the heat patterns of thermal images. We found that 49 (1–4 teats in 16 cows) of the 252 teats were suspected of mastitis and 203 teats appeared normal. Our results showed that cows suspected of mastitis presented teat skin surface temperature (TSST) values that were 5.05°C higher, on average, then those of healthy cows. Moreover, TSST values were well correlated with both high somatic cell count values (r=0.99; P&lt;0.001) and California mastitis test scores (r=0.59; P&lt;0.001), indicating that TSST temperature monitoring using IRT could represent an easy and reliable method for screening for mastitis in dairy cows breeding farms.

Milk Immune Cell Composition in Dromedary Camels With Subclinical Mastitis.

Mastitis represents one of the most important infectious diseases in camels with heavy economic losses due to reduced milk quantity and quality. Balanced immune cell composition and function in the mammary gland are essential for effective immune response to mastitis pathogens. The objective of the present study was to characterize the cellular immune response to subclinical mastitis in the mammary gland of dromedary camels. Therefore, immunostaining and flow cytometry were used to compare the cellular composition, leukocyte phenotype, and cell viability in camel milk from healthy she-camels (n = 8) and she-camels with subclinical mastitis (SCM; n = 6). In addition, the ex vivo phagocytic activity of milk phagocytes was compared between healthy and affected animals. The health status of the mammary gland was evaluated based on the California Mastitis Test (CMT) score. SCM (CMT score of ≥3 in the absence of clinical signs of mastitis) was found in six of the 56 sampled quarters (10.7 %) with only one affected quarter per animal. In comparison to milk from healthy camels, milk from SCM animals showed higher somatic cell count (SCC), higher numbers of CD45+ leukocytes with an expanded fraction of CD172a+ myeloid cells. Within the myeloid cell population, there was an increase in the percentage of granulocytes (CD172a+CD14low) with a decreased percentage of macrophages (CD172a+CD14high) in milk from affected animals compared to healthy animals. The decrease in lymphoid cells in SCM milk was mainly due to the decreased fraction of CD4+ helper T cells. Camel SCM was also associated with a stimulated phenotype, increased cell viability, and enhanced phagocytic activity of the milk phagocytes, macrophages and granulocytes. Collectively, the present study identified significant changes in SCC, leukocyte count, phenotype, viability, and function in association with subclinical mastitis in camels. The results of the present study support a better understanding of host-pathogen interaction mechanisms in the camel mammary gland.

Relatedness of California Mastitis Test Scores and Bacteriological Plate Counts in the diagnosis of Subclinical Mastitis in white Fulani cattle from selected dairy herds

Background Subclinical mastitis remains a major challenge in the dairy industries as it affects nutritional content of milk and milk products, volume of milk production and also leads to economic loss. This study was carried out to determine the relationship between California Mastitis Test (CMT) scores and bacteria counts in the diagnosis of subclinical mastitis. A total of 339 white Fulani cattle milk samples were aseptically collected from six geographical regions of Plateau State and screened for mastitis and bacteriological analysis using the California Mastitis Test (CMT), Total Bacterial Count (TBC) and Total Coliform Count (TCC) methods respectively. Results The result of the study reveals that 31.0% of the milk samples were positive for mastitis. Based on the CMT scores, 61.9% of the samples were CMT negative, 7.1% were CMT trace while 6.5%, 11.5% and 13.0% were CMT +, CMT ++ and CMT +++ respectively. Most of the CMT negative samples (55.71%) were culture negative while almost all the CMT +++, were positive (90.91%) culture positive. A positive correlation was observed between CMT scores and plate counts (Total Bacteria count and Total Coliform Count). The Total Bacteria count ranged from 5.7x101 – 5.9x106 CFU/mL while the Total Coliform Count ranged from 0.6x101 – 3.0x105.CMT scores correlates well with bacteriological plate count of the mastitis milk samples. Conclusion There is a need for the improvement in quality and safety of dairy product because of public health risk associated with it

Relatedness of California Mastitis Test Scores and Bacteriological Plate Counts in the diagnosis of Subclinical Mastitis in white Fulani cattle from selected dairy herds

Background Subclinical mastitis remains a major challenge in the dairy industries as it affects nutritional content of milk and milk products, volume of milk production and also leads to economic loss. This study was carried out to determine the relationship between California Mastitis Test (CMT) scores and bacteria counts in the diagnosis of subclinical mastitis. A total of 339 white Fulani cattle milk samples were aseptically collected from six geographical regions of Plateau State and screened for mastitis and bacteriological analysis using the California Mastitis Test (CMT), Total Bacterial Count (TBC) and Total Coliform Count (TCC) methods respectively. Results The result of the study reveals that 31.0% of the milk samples were positive for mastitis. Based on the CMT scores, 61.9% of the samples were CMT negative, 7.1% were CMT trace while 6.5%, 11.5% and 13.0% were CMT +, CMT ++ and CMT +++ respectively. Most of the CMT negative samples (55.71%) were culture negative while almost all the CMT +++, were positive (90.91%) culture positive. A positive correlation was observed between CMT scores and plate counts (Total Bacteria count and Total Coliform Count). The Total Bacteria count ranged from 5.7x101 – 5.9x106 CFU/mL while the Total Coliform Count ranged from 0.6x101 – 3.0x105.CMT scores correlates well with bacteriological plate count of the mastitis milk samples. Conclusion There is a need for the improvement in quality and safety of dairy product because of public health risk associated with it.

Dairy Cows' Udder Pathogens and Occurrence of Virulence Factors in Staphylococci.

Simple SummaryDairy farmers and those involved in primary milk production face the challenge of maintaining the health of their animals. Although the level of technological support during milking has increased and appropriate veterinary measures are available, mastitis remains a major health problem in dairy cows as well as a major threat to dairy farm profitability. The results of this study indicate that, in addition to the major udder pathogens (S. aureus, S. uberis and S. agalactiae) causing dairy mastitis, non-aureus staphylococci (NAS) are a major risk to dairy cows during early lactation. NAS, such as S. chromogenes, S. warneri and S. xylosus, which were isolated from animals with clinical mastitis characterized by mild, moderate, or severe symptoms and persistent infections, had the highest representation of virulence factors (production of hemolysis, gelatinase and biofilm; the ability to hydrolyze DNA; resistance to antibiotics) in comparison to less virulent strains. In addition, isolates S. aureus and NAS showed resistance to one or more antimicrobials in 77.2%, and in 16 (11.7%) isolates, multi-drug resistance to three or more antimicrobial classes was confirmed. Due to the high resistance to β-lactam-antibiotics in two isolates of S. aureus and two species of NAS, the presence of a methicillin-resistant gene, mecA, was confirmed, which potentially poses serious complications for the treatment of dairy cows and a serious health risk to milk consumers.This study investigated 960 Slovak and Czech spotted cattle from four different conventional (non-organic) dairy herds located in Eastern Slovakia and Czechia during early lactation (14–100 days after calving). Dairy cows were examined clinically; milk from fore-stripping of each udder quarter was subjected to sensory examination and assessed by the California mastitis test (CMT), and laboratory analyses of bacterial pathogens in milk, including virulence factors, were conducted. Positive CMT scores (1–3) for one or more quarters were detected in 271 (28.2%) of the examined animals. Out of 230 infected milk samples, representing 24.0% of all dairy cows, staphylococci (59.1% of positive findings) were the most commonly isolated organisms, followed by E. coli (11.3%), streptococci Str. uberis (9.1%) and Str. agalactiae (3.4%), and enterococci (6.1%). From 136 isolates of S. aureus (38 isolates) and non-aureus staphylococci (NAS; 98 isolates), virulence factors and their resistance to 14 antimicrobials were detected using the disk diffusion method, with PCR detection of the methicillin resistance gene, mecA. An increased incidence of clinical and chronic forms of mastitis has been reported in mastitic cows in which staphylococci, especially S. aureus and NAS (S. chromogenes, S. warneri, and S. xylosus), have been detected and compared to other isolated udder pathogens. From those species, S. aureus and isolates of NAS mentioned above showed multiple virulence factors that are more likely to hydrolyze DNA, hemolysis, produce gelatinase and biofilm, and have multi-drug resistance as compared to other less virulent staphylococci. Generally, the isolated staphylococci showed 77.2% resistance to one or more antimicrobials, in particular to aminoglycosides, β-lactams, macrolides, or cephalosporins. Isolates that showed the ability to form a biofilm were more resistant to more than one antimicrobial than isolates without biofilm production. Multi-drug resistance to three or more antimicrobial classes was recorded in 16 isolates (11.7%), and the presence of the mecA gene was also confirmed in two isolates of S. aureus and two species of NAS.

Subclinical mastitis in crossbred dairy cows: Staphylococcus spp. and risk factors in small holder dairy farms

Subclinical mastitis (SCM) is one of the major economic diseases of dairy cows. In the present cross-sectionalstudy, dairy cows (n=205) of small holding dairy farms were screened using California mastitis test (CMT) andprevalence of 12.19% was recorded. Holstein Friesian and Jersey crossbred cows showed highest CMT score of 2followed by 3, 1 and T; linear scores of somatic cell counts (SCC) of 3.14±0.08, 4.72±0.25, 6.17±0.12, 7.99±0.11and 9.84±0.45 were observed for CMT scores N, T, 1, 2 and 3, respectively. Risk factors associated with SCM werestudied in 25 randomly selected cows. Staphylococcus species were detected in 54% of quarters based on PCRamplification of 16s rRNA gene; thermonuclease (nuc gene) PCR categorized Staphylococcus species as S. aureus(SA, 37%) and non-aureus Staphylococci (NAS, 26%). Significant association between CMT score 2 andStaphylococcus species was established. Staphylococcus species, SA and NAS, were detected in 30.7, 20.5 and17.9% of SCM negative as well as 68.85, 47.54 and 31.14% SCM positive quarters, respectively. Significantassociation between SCM and Staphylococcus species and Staphylococcus aureus was observed. Study indicatedstrong association between SCM, Staphylococcus aureus and certain risk factors among cows reared under smallholding dairy farms of the tropical region.

Bacteriological outcomes following random allocation to quarter-level selection based on California Mastitis Test score or cow-level allocation based on somatic cell count for dry cow therapy

Intramammary infusion of antimicrobials at the end of lactation (dry cow therapy) has been a cornerstone of mastitis management for many years. However, as only a proportion of cows are infected at this time, treating only those cows likely to be infected is an important strategy to reduce antimicrobial usage and minimize risk of emergence of antimicrobial resistance. Such an approach requires the ability to discriminate between cows and quarters likely to be infected and uninfected. This study compared assignment of cows or quarters to antimicrobial treatment at the end of lactation based on cow composite somatic cell count (SCC; i.e., all quarters of cows with a maximum SCC across lactation >200,000 cells/mL received an antimicrobial; n = 891 cows, SCC-group) or assignment to quarter-level treatment based on a quarter level California Mastitis Test (CMT) score ≥ trace (n = 884 cows; CMT-group) performed immediately before drying off. All quarters of all cows also received an infusion of a bismuth-based internal teat sealant. Milk samples were collected for microbiology following the last milking, and again within 4 d of calving. Clinical mastitis records from dry off to 30 d into the subsequent lactation were collected. Multilevel, multivariable models were used to assess the effect of assignment to antimicrobial treatment. At drying off, a total of 575 (8.8%) and 147 (2.3%) of the 6,528 quarters had a minor, and a major intramammary infection (IMI), respectively. At drying off, 2089/3270 (63.9%) and 883/3311 (26.7%) of quarters were treated with dry cow therapy in the CMT and SCC-groups, respectively. Apparent bacteriological cure proportion for any IMI was higher in quarters assigned to the CMT than the SCC-group (349/368 (0.95, 95% CI 0.92-0.97) versus 313/346 (0.90, 95% CI 0.87-0.93)). New IMI proportion was lower among quarters assigned to the CMT than SCC-group [101/3,212 (0.032, 95% CI 0.025-0.038) versus 142/3,232 (0.044, 95% CI 0.036-0.051)]. The prevalence of any IMI postcalving was lower in quarters assigned to the CMT than SCC-group [119/3,243 (0.037, 95% CI: 0.030-0.044) versus 173/3,265 (0.054, 95% CI: 0.045-0.062)]. There was no difference in incidence of clinical mastitis between treatment groups. The total mass of antimicrobials used was 63% higher in the CMT-group than in the SCC-group (3.47 versus 2.12 mg/kg of liveweight). Selection of quarters for antimicrobial treatment at the end of lactation based on CMT resulted in greater proportion undergoing bacteriological cure, reduced risk of any new IMI and reduced post calving prevalence of any IMI compared with selection of cows based on SCC. However, CMT-based selection resulted in higher antimicrobial use compared with SCC-based selection, and further research is required to analyze the cost benefit and impact on risk of antimicrobial resistance of these 2 strategies.