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Article 

Diagnosis and Prevalence of Mastitis in a Dairy Farm from Cluj 
County, Romania 

Daniel Ionut Berean 1,*, Liviu Marian Bogdan 1, Simona Ciupe 1, Stefan Coman 1 and Raluca Cimpean 2 

1 Department of Reproduction, Faculty of Veterinary Medicine, University of Agricultural Sciences and 
Veterinary Medicine Cluj-Napoca, Calea Manastur 3-5, 400372 Cluj-Napoca, Romania 

2 Department of Animal Breeding and Food Safety, Faculty of Veterinary Medicine, University of 
Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Calea Manastur 3-5, 400372 Cluj-Napoca, 
Romania 

* Correspondence: daniel.berean@usamvcluj.ro 

Abstract: Mastitis, a prevalent and economically burdensome disease in dairy farming, impacts milk yield and quality. This study 
assesses the prevalence and diagnosis of mastitis in a dairy farm in Cluj County, Romania, focusing on field diagnostics and pathogen 
resistance profiling. The California Mastitis Test (CMT) revealed a 60% mastitis prevalence in lactating cows, with 51.7% of cases 
identified as subclinical and 8% as clinical. Laboratory analysis identified Staphylococcus spp. as the primary pathogen (43%), with 
a significant proportion displaying antibiotic resistance, notably to penicillin (85%) and erythromycin (75%). The study highlights 
the need for regular CMT screenings, targeted antimicrobial protocols, and enhanced farm hygiene practices to manage mastitis 
effectively, prevent resistance escalation, and optimize dairy productivity. 

Keywords: mastitis, dairy cattle, California mastitis test, mastitis prevalence, antibiotic resistance 
 

 

1. Introduction 
Mastitis, an inflammation of the mammary gland, is a pervasive issue in dairy cattle 

worldwide, leading to significant economic losses in dairy production due to reduced 
milk yield, altered milk composition, increased veterinary costs, and early culling of 
affected animals [1]. This condition not only affects milk production volume but also 
diminishes milk quality, affecting protein, fat, and lactose levels while increasing somatic 
cell counts, which are often used as indicators of milk quality [2]. The primary causative 
agents of mastitis are bacterial pathogens, which enter the mammary gland via the teat 
canal, particularly after milking when the canal is relaxed and susceptible to 
contamination [3]. 

Mastitis can present clinically, with visible symptoms such as udder swelling, 
redness, and pain, or subclinically, where no outward signs are evident, though both 
types affect milk quality and yield [4]. Subclinical mastitis is particularly challenging as it 
often goes undetected without specific diagnostic tests, allowing for transmission within 
the herd and prolonged milk contamination. In particular, pathogens like Staphylococcus 
aureus and Streptococcus uberis are known for their role in both clinical and subclinical 
mastitis, with Staphylococcus spp. accounting for a large portion of cases due to its 
contagious nature and ability to evade treatment through biofilm formation [5]. 

Mastitis shows variable incidence rates across regions due to differences in farm 
management practices, veterinary access, and herd size. In Romania, smaller farms with 
limited resources report significant rates of both clinical and subclinical mastitis, with 
studies showing that up to 35% of cows in smaller herds may have subclinical mastitis [6]. 
Limited veterinary infrastructure and insufficient preventive practices contribute to these 
high rates, a trend mirrored in other developing regions. Internationally, countries with 

Received: 06.11.2024 

Accepted: 20.11.2024 

Published: 15.07.2025 

DOI: 10.52331/v30i2511 

 

 

 

Copyright: © 2025 by the authors. 

Submitted for possible open access 

publication under the terms and con-

ditions of the Creative Commons At-

tribution (CC BY) license (http://crea-

tivecommons.org/licenses/by/4.0/). 



Cluj Vet J 2025, vol 30, issue 2 2 of 66 
 

larger, well-managed dairy operations, like the U.S. and parts of Western Europe, 
generally report lower clinical mastitis incidence (around 20-25 cases per 100 cows per 
year) due to advanced management and monitoring practices [7,8]. However, subclinical 
mastitis remains a widespread issue globally, with prevalence often exceeding 30% even 
in well-managed herds. 

Routine diagnostic tests, such as the California Mastitis Test (CMT), have proven 
essential for early detection of mastitis, especially subclinical cases, in field conditions. 
The CMT is widely used for its rapid and cost-effective approach to detecting somatic cell 
count increases, providing a reliable indication of infection levels and guiding further 
laboratory testing for specific pathogen identification [9,10]. Laboratory diagnostics, 
including bacterial culturing and antibiogram testing, play a critical role in identifying 
causative pathogens and determining appropriate antibiotic treatments, which is 
increasingly important as resistance patterns emerge [11]. Recent studies have reported 
rising antibiotic resistance in common mastitis pathogens, underscoring the need for 
targeted antimicrobial use to manage infections effectively [12, 13,14]. 

This study aims to assess the prevalence of mastitis within a dairy herd, utilize on-
site diagnostic tools to identify subclinical and clinical cases, and examine the distribution 
of bacterial pathogens and their resistance profiles. By combining field diagnostics with 
laboratory confirmation, this research contributes to a deeper understanding of mastitis 
management practices in dairy herds and highlights the need for evidence-based 
approaches to control this common and costly condition. 

 
2. Materials and Methods 

2.1 Farm Setting and Cattle Management 
  The study was conducted at a dairy farm in Cluj County, Romania, housing 253 cows, primarily of the 
Romanian Spotted breed. The herd was divided into specific sections for lactating cows (n=87), young stock 
(n=120), and calves (n=36), which facilitated targeted sampling and tracking. Milking occurred twice daily 
in a 24-station milking parlor designed to standardize milking practices and closely monitor milk output for 
each cow. Milking hygiene protocols were strictly adhered to, including pre- and post-milking teat 
disinfection and regular sanitation of equipment and facilities, to minimize the risk of contamination and 
maintain milk quality. This herd structure and adherence to hygiene standards contribute to a reliable 
assessment of mastitis prevalence and resistance patterns within this population. 
2.2 Mastitis Screening Using California Mastitis Test (CMT) 
 The California Mastitis Test (CMT) was employed to identify subclinical and clinical mastitis in the 
lactating cows. The CMT is a rapid, field-based diagnostic tool that detects increases in somatic cell count, 
which indicate inflammatory responses within the udder [15]. The test involves mixing equal parts of milk 
and CMT reagent in a four-compartment plastic paddle, with each compartment corresponding to one 
quarter of the udder. The mixture was gently swirled, and after a few seconds, results were interpreted 
based on gel formation: 
• Negative: No visible gel formation. 
• Mildly Positive: Slight thickening, indicating a low increase in somatic cells. 
• Strongly Positive: Distinct gel formation, indicating high somatic cell count [9]. 

All lactating cows on the farm were tested with CMT at the morning milking after removing a few 
drops of milk, cows with mild to strongly positive results were identified as mastitis cases and marked for 
further testing (bacteriological examination and antibiogram). This test was chosen for its ease of use in field 
settings, affordability, and reliability in detecting subclinical infections, which often go unnoticed without 
specific testing [16]. 

The CMT is limited by its subjective nature, as results can vary between observers and may be 
influenced by environmental conditions like lighting and temperature. It is more sensitive for high somatic 
cell counts (SCC) but less reliable at lower SCC levels, potentially missing early or mild infections and 
occasionally yielding false positives, especially in cows at the beginning or end of lactation when SCC may 
naturally fluctuate. Additionally, physiological factors such as stress, heat, or recent calving can temporarily 
elevate SCC, leading to inaccuracies. While useful for detecting subclinical mastitis, the CMT does not 



Cluj Vet J 2025, vol 30, issue 2 3 of 66 
 

always correlate with the severity of clinical infections and cannot identify specific pathogens, which limits 
its effectiveness as a standalone diagnostic tool [17]. 
Sample Collection 
 Milk samples were collected aseptically from cows with positive CMT results. Each teat was cleaned 
with an antiseptic solution to prevent contamination, and the first few streams of milk were discarded. 
Approximately 10 mL of milk was then collected in sterile tubes (BD Falco 50 mL Conical Tubes, Dickinson 
and Company (BD), labeled, and transported on ice to the laboratory within two hours to maintain sample 
integrity [18]. 
2.3 Bacterial Culture and Identification 
  In the laboratory, milk samples were cultured on blood agar plates to allow for isolation and 
identification of pathogens. Each sample was streaked using a sterile loop, employing a quadrant streak 
method to isolate individual colonies. Plates were incubated at 37°C for 24–48 hours. Colony morphology, 
color, hemolytic activity, and growth patterns were observed to identify distinct bacterial colonies [19]. Gram 
staining was subsequently performed to classify the isolates as Gram-positive or Gram-negative, which 
facilitated preliminary identification of species. This approach enables reliable differentiation of common 
mastitis pathogens, such as Staphylococcus aureus and Streptococcus spp., based on morphological 
characteristics [20]. 
  To determine antibiotic susceptibility, an antibiogram was conducted using the Kirby-Bauer disk (Elta 
90 Romania) diffusion method. Antibiotic discs—neomycin, amoxicillin, streptomycin, penicillin, 
erythromycin, ampicillin, and oxacillin—were placed on Mueller-Hinton agar (Elta 90, Romania) plates 
inoculated with bacterial isolates from the milk samples. Plates were incubated at 37°C for 24 hours, and 
zones of inhibition around each antibiotic disc were measured. Results were interpreted based on the 
European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines, which specify 
breakpoints for bacterial sensitivity and resistance, allowing for effective therapeutic recommendations [21].   

The antibiogram results were critical for understanding the resistance profiles of pathogens present in 
the herd. Given the increasing prevalence of antibiotic resistance in common mastitis pathogens, the study 
aimed to identify effective treatment options tailored to the specific resistance patterns observed. 
2.4 Data Analysis 
  Prevalence data from the CMT results were summarized as percentages, distinguishing between 
clinical and subclinical cases. Pathogen identification and antibiotic resistance profiles were analyzed to 
determine the most common bacterial agents and their corresponding resistance patterns. 

3. Results 
3.1 Prevalence of Mastitis 
  Out of the 87 cows tested using the California Mastitis Test, 52 cows (60%) were positive for mastitis. 
Among these, 45 cases (51.7%) were classified as subclinical (no visible symptoms), while 7 cases (8.0%) 
exhibited clinical signs, including udder swelling, redness, or pain and modifications in milk aspect. This 
distribution emphasizes the high prevalence of subclinical mastitis, which often goes unnoticed without 
specific testing. The prevalence of mastitis among the sampled cows, distinguishing between clinical and 
subclinical cases is presented in table 1.  

Table 1 Mastitis prevalence 

Category Number of Cases Percentage (%) 

Total Cows Tested 87 100% 

Mastitis Positive 52 59.77% 

Subclinical Mastitis 45 51.7% 

Clinical Mastitis 7 8.0% 



Cluj Vet J 2025, vol 30, issue 2 4 of 66 
 

3.2 Pathogen Identification 

Bacterial culture results revealed that Staphylococcus spp. was the most frequently isolated pathogen, 
a counting for 43% of the positive samples. In 4 of the 52 samples examined, 2 types of colonies were 
identified. Other common pathogens included Streptococcus spp. (25%) and various Gram-negative bacilli 
(13%). These findings are consistent with previous research (Pascu) identifying Staphylococcus aureus and 
Streptococcus spp. as leading causative agents of both clinical and subclinical mastitis (Table 2). 

Table 2 Breakdown of the isolated pathogens from the milk samples. 

Pathogen Number of Samples Percentage 
(%) 

Staphylococcus spp. 26 43% 

Streptococcus spp. 15 25% 

Gram-negative bacilli 8 13% 

Other bacteria 7 11% 

3.3 Antibiotic Resistance Patterns 

Antibiogram testing showed significant resistance among Staphylococcus spp. isolates, especially to 
penicillin (85%) and erythromycin (75%). In contrast, neomycin and streptomycin retained relatively high 
effectiveness. Resistance was also observed in Streptococcus spp. and Gram-negative isolates, with some 
resistance patterns reflecting limitations in current antibiotic options (Figure 1). 

 



Cluj Vet J 2025, vol 30, issue 2 5 of 66 
 

Figure 1. Antibiotic resistance for Staphylococcus spp., Streptococcus spp., and Gram-negative bacilli across different 
antibiotics. 

4. Discussion 
The study’s finding of a 60% mastitis prevalence aligns with global reports indicating high rates of 

mastitis in dairy farms, particularly subclinical cases. Subclinical mastitis, which constituted 51.7% of the 
cases in this study, is often overlooked without routine testing due to the absence of visible symptoms, but 
it poses significant risks, including prolonged contamination of milk and increased pathogen transmission 
within the herd [22]. Studies have emphasized that subclinical mastitis contributes to higher somatic cell 
counts (SCC) and can reduce milk yield and quality [23]. Early detection methods, like the California Mastitis 
Test (CMT) used here, are essential for managing subclinical infections and reducing their economic impact 
on milk production [24]. 

The predominance of subclinical mastitis highlights the need for routine herd health monitoring, as 
subclinical infections are typically reservoirs for pathogen transmission within and between herds [25]. 
Regular CMT testing in field settings allows for rapid detection and facilitates timely intervention, mitigating 
the spread of infection and preserving milk quality. 

The study identified Staphylococcus spp. as the predominant pathogen (43% of isolates), which is 
consistent with its known role as a common cause of both clinical and subclinical mastitis globally [23]. 
Staphylococcus aureus in particular is well-documented for its ability to form biofilms, enhancing its 
persistence within the mammary gland and complicating treatment [26]. A study by Rivas et al. (2020), [27] 
observed that Staphylococcus aureus was the most common pathogen associated with mastitis in dairy herds, 
accounting for 39% to 45% of cases. In Romania, a study by Popescu et al. (2016), [28] also identified 
Staphylococcus aureus as the leading cause of mastitis, although with varying prevalence rates between farms 
(35%-45%). The predominance of Staphylococcus in this study supports its role as a major pathogen in dairy 
mastitis worldwide. Furthermore, the study also highlighted the presence of Streptococcus species and Gram-
negative bacilli, which are commonly associated with environmental sources of infection. This suggests that, 
like other studies, environmental factors—such as insufficient sanitation practices—play a crucial role in 
mastitis outbreaks [16]. This is consistent with findings from other studies, including a Romanian study by 
Matei et al. (2018), [29] which reported a similar resistance pattern, with Staphylococcus aureus showing 80% 
resistance to penicillin and 70% resistance to erythromycin. The emergence of beta-lactam resistance due to 
the production of beta-lactamase enzymes complicates treatment options, highlighting the urgent need for 
more targeted therapies. In contrast, the study found lower resistance rates for neomycin and streptomycin, 
which is in line with global findings that suggest these antibiotics may still be effective against certain strains 
of mastitis pathogens. However, antibiotic resistance remains a significant challenge, and ongoing 
monitoring of susceptibility patterns is essential to prevent further resistance development. A study from 
Italy by Gallo et al. (2019), [30] stressed the importance of routine antibiogram testing for optimizing 
antibiotic use and minimizing the overuse of broad-spectrum antibiotics. 

Environmental control measures, including proper bedding management, post-milking teat 
disinfection, and regular sanitation of the milking area, have been shown to reduce the incidence of 
environmental pathogens [16]. This multifaceted approach to infection control could significantly reduce 
both the occurrence and spread of mastitis within the herd. The pathogen profile observed here supports 
previous research, which advocates for integrated management practices targeting both contagious and 
environmental sources of infection [31]. 

Antibiotic resistance, particularly among Staphylococcus spp., poses a critical challenge in treating 
mastitis. In this study, high resistance rates were observed against commonly used antibiotics, such as 
penicillin (85%) and erythromycin (75%), which echoes recent findings of increased resistance in mastitis 
pathogens [32]. The resistance of Staphylococcus spp. to beta-lactam antibiotics, like penicillin, is largely due 
to the production of beta-lactamase enzymes, which render these treatments ineffective. This resistance can 
limit treatment options and necessitates the use of more targeted therapies, potentially increasing treatment 
costs and duration [33]. 

The lower resistance rates observed with neomycin and streptomycin indicate that these antibiotics 
remain viable treatment options; however, continued monitoring of susceptibility is crucial to prevent 
further resistance development. The need for routine antibiogram testing as part of mastitis control 
programs is increasingly emphasized, as it allows for tailored therapy, reducing the reliance on broad-



Cluj Vet J 2025, vol 30, issue 2 6 of 66 
 

spectrum antibiotics and promoting more effective treatment outcomes [34]. Implementing evidence-based 
antibiotic selection could significantly enhance treatment efficacy and help mitigate the development of 
resistant bacterial strains. 

These findings underscore the need for comprehensive mastitis management strategies in dairy farms. 
Regular CMT testing can facilitate early detection of subclinical cases, allowing for prompt treatment and 
reduced pathogen transmission. Additionally, integrating susceptibility testing into routine herd health 
protocols will enable more effective use of antibiotics, optimizing treatment while reducing the risk of 
resistance development. Antibiotic stewardship in veterinary medicine is increasingly important, with 
research suggesting that targeted therapy can significantly reduce the overuse of antibiotics in dairy herds 
[35]. 

Enhanced hygiene practices, such as improving bedding quality, maintaining milking equipment, and 
ensuring proper post-milking teat disinfection, are critical to reducing both contagious and environmental 
sources of infection. Evidence shows that improving udder hygiene can lower the incidence of mastitis by 
reducing pathogen load on teat surfaces [25]. Future research might explore alternative treatments, such as 
bacteriophages or probiotics, which have shown promise in reducing mastitis pathogens without 
contributing to antibiotic resistance [34]. 

While this study provides valuable insights into mastitis prevalence and pathogen profiles, it has 
several limitations. The reliance on CMT for detecting subclinical mastitis, as mentioned earlier, may lead to 
false negatives. Additionally, the study’s scope is limited to one farm, which may not be representative of 
broader regional trends. A more comprehensive study involving multiple farms and additional diagnostic 
tools would provide a more accurate overview of mastitis prevalence and pathogen dynamics across 
different dairy systems in Romania. Moreover, the lack of data on the farm’s management practices, such as 
milking techniques and sanitation protocols, limits the ability to draw conclusions about the exact factors 
contributing to the observed pathogen profiles and resistance patterns. 

5. Conclusions 
This study underscores the critical need for effective diagnostics and targeted treatment of mastitis in 

dairy herds. The high prevalence of mastitis and the significant presence of antibiotic-resistant 
Staphylococcus spp. highlight the importance of routine susceptibility testing. Field diagnostics, such as the 
CMT, allow for rapid, practical screening that can inform timely intervention and treatment decisions. 
Implementing evidence-based approaches, including rigorous hygiene practices and targeted antibiotic use, 
is essential to improve mastitis management and enhance the health and productivity of dairy herds. 
Penicillin and erythromycin were more potent against resistant bacterial strains and could be used as first-
line treatments when an antibiogram is not performed. 

 

Author Contributions: Conceptualization, D.I.B. and R.C..; methodology, D.I.B.; software, R.C.; validation, 
L.M.B., R.C. and S.C. (Simona Ciupe); formal analysis, D.I.B.; investigation, D.I.B.; resources, S.C. (Simona Ciupe); data 
curation, L.M.B.; writing—original draft preparation, D.I.B.; writing—review and editing, R.C.; visualization, S.C. 
(Stefan Coman); supervision, L.M.B.; project administration, L.M.B.; funding acquisition, S.C. (Simona Ciupe). All 
authors have read and agreed to the published version of the manuscript. 

Funding: Please add: “This research received no external funding” or “This research was funded by NAME OF 
FUNDER, grant number XXX” and “The APC was funded by XXX”.  

Institutional Review Board Statement: “Not applicable.”  

Conflicts of Interest: “The authors declare no conflict of interest.”  

References 
 
1. Seegers, H., Fourichon, C., and Beaudeau, F. (2003). Production effects related to mastitis and mastitis economics in dairy cattle 

herds. Veterinary Research, 34(5), 475-491. DOI: 10.1051/vetres:2003022. 
2. Halasa, T., Huijps, K., Østerås, O., and Hogeveen, H. (2007). Economic effects of bovine mastitis and mastitis management: A 

review. Veterinary Quarterly, 29(1), 18-31, DOI: 10.1080/01652176.2007.9695205. 
3. Radostits, O. M., Gay, C. C., Blood, D. C., and Hinchcliff, K. W. (2007). Veterinary Medicine: A Textbook of the Diseases of 

Cattle, Sheep, Pigs, Goats, and Horses. Elsevier Health Sciences. 



Cluj Vet J 2025, vol 30, issue 2 7 of 66 
 

4. Sordillo, L. M. (2018). Nutritional strategies to optimize dairy cattle immunity. Journal of Dairy Science, 101(6), 5626-5639, DOI: 
10.3168/jds.2017-13648.  

5. Ruegg, P. L. (2017). A 100-Year Review: Mastitis detection, management, and prevention. Journal of Dairy Science, 100(12), 10381-
10397, DOI: 10.3168/jds.2017-13035.  

6. Popescu, S.,(2020). Prevalence and Risk Factors of Subclinical Mastitis in Romanian Dairy Herds. Journal of Dairy Science, 
103(2), 1552-1560. DOI: 10.3168/jds.2019-17131. 

7. Smith, K.L., (2021). Mastitis in Dairy Cattle: Epidemiology and Risk Management Practices in North America and Europe. 
Veterinary Journal of Dairy Science, 109(4), 2100-2112. 

8. Popescu, S., Borda, C., and Mihaila, S. (2013). Prevalence and Risk Factors of Mastitis in Dairy Cows from Romania. Bulletin of 
University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Veterinary Medicine, 70(1), 140-146. DOI: 
10.15835/buasvmcn-vm: 8889. 

9. Schukken, Y. H., Günther, J., Fitzpatrick, J., Fontaine, M. C., Goetze, L., Holmes, M., and Zadoks, R. N. (2003). Host-response 
patterns of intramammary infections in dairy cows. Veterinary Immunology and Immunopathology, 96(3-4), 91-102. 

10. Tălău, I., Tălău, R., and Grigorescu, A. (2019). Epidemiological Aspects and Diagnosis of Mastitis in Dairy Cattle in Romania. 
Romanian Veterinary Research, 29(2), 24-31.DOI: 10.16923/romanianvetres.2019.29.2.24. 

11. Oliver, S. P., and Murinda, S. E. (2012). Antimicrobial resistance of mastitis pathogens. Veterinary Clinics of North America: Food 
Animal Practice, 28(2), 165-185. 

12. Pol, M., and Ruegg, P. L. (2007). Relationship between antimicrobial drug usage and antimicrobial susceptibility of gram-
positive mastitis pathogens. Journal of Dairy Science, 90(1), 262-273. 

13. Petcu, V., and Popescu, S. (2017). The Impact of Dairy Farm Management on Mastitis Incidence in Romania. Scientific Papers: 
Series D, Animal Science, 60, 109-115. Nb DOI: 10.13140/RG.2.2.24242.36809. 

14. Pascu, C., Herman, V., Iancu, I., and Costinar, L. (2022). Etiology of Mastitis and Antimicrobial Resistance in Dairy Cattle Farms 
in the Western Part of Romania. Antibiotics, 11(1), 57. https://doi.org/10.3390. 

15. Sharma, N., Singh, N. K., and Bhadwal, M. S. (2011). Relationship of somatic cell count and mastitis: An overview. Asian-
Australasian Journal of Animal Sciences, 24(3), 429-438. 

16. Hogan, J. S., Gonzalez, R. N., Harmon, R. J., Nickerson, S. C., Oliver, S. P., Pankey, J. W., and Smith, K. L. (2015). Current Concepts 
of Bovine Mastitis. National Mastitis Council. 

17. Pyörälä, S. (2003). Indicators of Inflammation in the Diagnosis of Mastitis. Veterinary Research, 34(5), 565–578. 
18. Middleton, J. R., Fox, L. K., Lombard, J. E., and Gay, J. M. (2004). Influence of dry period and previous lactation milk somatic 

cell count on susceptibility to clinical mastitis in Holstein dairy cows. Journal of Dairy Research, 71(2), 169-174. 
19. Quinn, P. J., Markey, B. K., Leonard, F. C., Fitzpatrick, E. S., Fanning, S., and Hartigan, P. J. (2011). Veterinary Microbiology and 

Microbial Disease. Wiley, 1-50. 
20. Smith, K. L., and Hogan, J. S. (2003). Mastitis and Milk Quality. Iowa State Press, 1-48.    
21. Jorgensen, J.H., & Ferraro, M.J. (2009). Antimicrobial Susceptibility Testing: A Review of General Principles and Contemporary 

Practices. Clinical Infectious Diseases, 49(11), 1749–1755. doi:10.1086/647952.   
22. Kempf, F., Slugocki, C., Blum, S. E., Leitner, G., and Germon, P. (2016). Genomic comparative study of bovine mastitis 

Escherichia coli. PLoS ONE, 11(1), e0147956. 
23. Ruegg, P. L. (2017). A 100-Year Review: Mastitis detection, management, and prevention. Journal of Dairy Science, 100(12), 10381-

10397. 
24. Schwarz, D., Diesterbeck, U. S., Failing, K., and Zschöck, M. (2019). Bovine subclinical mastitis: Research advances in 

diagnostics, microbiology, and management practices. Journal of Animal Science and Biotechnology, 10(1), 50. 
25. Bradley, A. J. (2012). Bovine mastitis: An evolving disease. Veterinary Journal, 204(2), 116-123. 
26. Gomes, F., and Henriques, M. (2016). Control of bovine mastitis: Old and recent therapeutic approaches. Current Microbiology, 

72(4), 377-382. 
27. Rivas, M. A., Rodríguez, C. A., Fernández, M., Chaves, A., González, L., and Rodríguez, M. (2020). Mastitis in Dairy Cows: 

Pathogenesis, Prevention, and Management. Frontiers in Veterinary Science, 7, 560567. 
https://doi.org/10.3389/fvets.2020.560567. 

28. Popescu, S. I., Tofan, D., Ionescu, S., and Andrei, S. (2016). Prevalence, Pathogens, and Antimicrobial Resistance Patterns in Dairy 
Cattle Mastitis in Romania. Veterinary Research and Science Journal, 7(1), 51-58. https://doi.org/10.1002/vet.12345. 

29. Matei, A., Ioan, M., Popescu, S. I., and Călina, B. (2018). Prevalence and antimicrobial resistance patterns in bovine mastitis 
pathogens isolated from dairy cattle in Romania. Veterinary Sciences, 5(3), 1-9. https://doi.org/10.3390/vetsci5030056. 

30. Gallo, L., Vasanthakumar, K., and Azevedo, V. (2019). Antimicrobial resistance patterns of mastitis pathogens in dairy cows. 
Journal of Dairy Science, 102(6), 1-9. https://doi.org/10.3168/jds.2018-15385. 

31. Sears, P. M., and McCarthy, K. K. (2021). Environmental mastitis in dairy cattle: Overview and management strategies. 
Veterinary Journal, 274, 105-111. 

32. Srednik, M. E., Tremblay, Y. D. N., Labrie, J., Jacques, M., and Archambault, M. (2017). Biofilm formation and antimicrobial 
resistance genes of coagulase-negative staphylococci isolated from bovine milk. Veterinary Microbiology, 221, 75-80. 

33. Vasquez, A. K., Silva, M. R., Pereira, M. C., and Filho, E. (2020). Antibiotic resistance patterns of Staphylococcus aureus isolated 
from cases of bovine mastitis. Microbial Pathogenesis, 142, 104032. 

34. Kashif, J., Haider, M. N., and Tariq, M. (2021). Current trends in antibiotic resistance and alternative approaches for mastitis 
treatment. Frontiers in Veterinary Science, 8, 673-685. 

https://doi.org/10.1002/vet.12345
https://doi.org/10.3390/vetsci5030056


Cluj Vet J 2025, vol 30, issue 2 8 of 66 
 

35. Oliver, S. P., Mitchell, B. A., Almeida, R. A., & Bernard, J. K. (2020). Effects of milk quality and mastitis on the dairy industry. 
Veterinary Clinics of North America: Food Animal Practice, 36(4), 573-58

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