• Journal of Veterinary Clinics
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• v.3 no.1
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• pp.277-298
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• 1986

This paper reviews the mechanisms effecting host defense in the mammary gland and assesses their possible in preventing of bovine mastitis. The streak canal is the first line of defense against invading mastitis pathogens, providing a physical barrier and antibacterial substances. The milk leukocytes are a second defense line by ingesting pathogens breached the streak canal by multiplication, physical passage, and propulsion during milking. Leukocytosis in milk and enhancement of the phagocytic defense machanisms of the udder were accomplished by inserting intramammary devices. Milk antibodies serum derived and synthesized in mamma tissue aggregate and opsonise bacteria, agglutinate and neutralise toxins, and inhibit. binding of bacteria to epitherial surfaces. Vaccination generally has been unsuccessful because protection is not absolute, but immunization is useful in controlling specific pathogens. Immunostimulant to enhance locally the protective nature of antibody-producing plasma cells concentrated in internal teat end tissue may be effective in reducing the occurrence of infection, but ineffective in preventing intramammary infections.

• Korean Journal of Veterinary Research
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• v.45 no.1
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• pp.113-119
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• 2005

Resistance to antibiotics is a problem all over the world, and this problem also is so extended in veterinary fields. Therefore, this study aimed to find out the antibacterial substances from natural medicinal herbs against bovine mastitis pathogens, especially methicillin-resistant Staphylococcus aureus (MRSA). Among seventy two medicinal herbs, Terminaliae chebula extract showed antimicrobial effect against MRSA isolated from mastitis milk in cow and patient in human. However, Terminaliae chebula extract didn't show antibacterial effects on various strains including other contagious and environmental pathogens related with mastitis of dairy cows.

• Journal of Veterinary Clinics
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• v.27 no.3
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• pp.252-256
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• 2010

Bovine mastitis, defined as an inflammation of the mammary gland, is usually associated with bacterial infection. Thus, treatment and control of mastitis relies primarily on antimicrobial therapy. This study investigated the bactericidal actions of silver ion against causing various bovine mastitis pathogens. Minimal inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs) and bactericidal activity times and concentrations of silver ion against pathogens were determined. The effect of silver ion on bacterial morphology was studied by scanning electron microscopy (SEM). The MICs and MBCs of silver ion for various bacteria strains ranged from 1.9-15.6 ${\mu}g$/ml. SEM images indicated formation of a pit, distortion and disruption of cell walls in silver treated Staphylococcus aureus and Escherichia coli. The results demonstrate that silver ion has a bactericidal capacity against causing various pathogens of bovine mastitis and suggest that silver ions may be exploitable as a therapeutic/preventative tool of bovine mastitis.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.124-130
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• 2008

Streptococcus (Strep.) agalactiae is one of the major pathogens of bovine mastitis and is the main cause of subclinical infection. This study attempted to develop a rapid PCR diagnosis procedure using milk samples collected on filter paper disks. Chromatographic filter paper was employed as the preservation media and kept at room temperature for one to four weeks. The revival rate of Strep. agalactiae kept on dried filter paper disks was affected by the pretreatment preservation time. The revival test suggested that not all the bacteria in artificially contaminated milk samples on the filter paper disks could be recovered. After that, a PCR based on the 16-23S intergenic spacer region of Strep agalactiae was performed. The results distinguished the strep. agalactiae from major pathogens of bovine mastitis at a $2{\times}10^2$ colony forming units (CFU)/ml level, which showed similar sensitivity to the results from liquid milk samples. The results also showed that milk samples collected on filter paper disks could be kept at room temperature for one to four weeks with little negative effect on sensitivity and specificity. The field test showed that the diagnostic sensitivity and specificity was 96.15% and 98.60%, respectively. In conclusion, the protocol will provide a rapid and economic procedure for the detection of bovine mastitis.

• Korean Journal of Veterinary Research
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• v.44 no.3
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• pp.399-405
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• 2004

Haemophilus somnus, Mycoplasma bovis and Pasteurella multocida were responsible for respiratory diseases in bovine. Methods for identifying these bacteria had poor sensitivity and specificity. In this paper, PCR assays were applied for rapid identification of H. somnus, M. bovis, P. multocida B:2 and P. multocida capsular types. The specific PCR products were amplified from H. somnus, but not from other bacteria. Ten-fold diluted H. somnus were mixed with P. multocida and then the mixed cultures were inoculated on agar plates. After incubation, PCR was performed with harvest from agar plates and could detect as few as 3.4 CFU/ml of H. somnus. The primers MboF and MboR produced an amplification product unique to M. bovis and sensitivity of PCR was as low as 100 pg of DNA. Only serotype B:2 of P. multocida, the causal agent of haemorrhagic septicemia in bovine, was specifically amplified in PCR among the 16 reference serotypes. The multiplex capsular PCR typing for P. multocida was produced the P. multocida specific product as well as the capsular serogroup-specific product. The present PCR assays should be useful for the rapid identification of bacterial pathogens from bovine respiratory diseases.

• Journal of Veterinary Clinics
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• v.25 no.5
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• pp.346-354
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• 2008

The combined effects of EDTA-Tris and eighteen antimicrobial agents have been evaluated in eight clinically isolated methicillin-resistant bacteria (Staphylococcus aureus, Escherichia coli, Streptococcus uberis and Streptococcus agalactiae) from bovine mastitis. The antimicrobial activity was evaluated by measuring the minimal bactericidal concentration (MBC) for the antibiotics alone or in combination with EDTA-Tris in Mueller-Hilton broth and milk. Combined use of EDTA-Tris and antibiotics potentiated or antagonized activity of antibiotics against mastitic pathogens. Milk increased the antibiotic potency of erythromycin and spiramycin on S. aureus. Culture in milk changed patterns of EDTA-Tris combinational effects compared with that in standard Mueller-Hilton broth. Combined with EDTA-Tris in milk, synergic effects were observed in colistin, dihydrostreptomycin, kanamycin, erythromycin, gentamycin, oxytetracycline, streptomycin to E. coli, Str. uberis, and Str. agalactiae. However, significant antagonistic effects of milk on antibiotic susceptibility in combination with EDTA-Tris were noted in neomycin, streptomycin, penicillin, roxithromycin, and amoxicillin. This study indicates that combination therapy of EDTA-Tris with antibiotics in bovine mastitis should be used with caution because of the possible antagonistic effects of antibiotic combination with EDTA-Tris on mastitic pathogens. In addition, antibiotic susceptibility test in combination with EDTA-Tris in milk culture condition can be benefit in search of effective treatment regimen for some antibiotic-resistant bacteria of mastitis.

• Korean Journal of Veterinary Service
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• v.45 no.3
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• pp.201-209
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• 2022

An epidemiological study was conducted to investigate five diarrhea-causing pathogens (coronavirus, rotavirus, E. coli, Cryptosporidium, Giardia) using a rapid diagnostic kit in Hanwoo calves with diarrhea in Chungcheongbuk-do, Korea, from 2018 to 2021. A total of 22,417 fecal samples were collected from calves under 1 year of age; of those, 13,518 (60.3%) were positive for five bovine diarrhea antigens. The antigen positivity rates for rotavirus, coronavirus, E. coli, Giardia, and Cryptosporidium were 34.5%, 11.0%, 8.2%, 4.7%, and 2.0%, respectively. The prevalence of the five pathogens in calves was statistically higher in autumn and winter. The highest prevalence of the pathogens was observed in the under 1 month age group, and the incidence of diarrhea decreased with age. Rotavirus was a major pathogen in calves under 1 month of age, whereas the prevalence of E. coli increased with age. This study provides epidemiological evidence of the prevalence of calf diarrheal pathogens in Chungcheongbuk-do, Korea, which will facilitate early diagnosis and development of measures against calf diarrhea.

• Journal of Veterinary Clinics
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• v.29 no.5
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• pp.377-383
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• 2012

Bovine diarrhea is a major economical burden to the bovine industry in Korea. Since multiple infectious agents can be involved in bovine diarrhea, differential diagnosis is essential for effective treatment. Therefore, a panel of two multiplex real-time PCR assays which can simultaneously detect six major bovine enteric pathogens [i.e., bovine viral diarrhea virus (BVDV), bovine coronavirus (BCoV), group A bovine rotavirus (BRV), Salmonella spp., Escherichia coli (E. coli) $K99^+$, and Cryptosporidium parvum] was developed and applied to test 97 fecal samples collected from cattle farms in Korea. In addition, microscopic examination was also preformed on the samples to detect Coccidium oocyst. The estimated sensitivity of the multiplex PCR was 0.1 $TCID_{50}$ for BVDV, BCoV and group A BRV, 5 and 0.5 CFU for E. coli $K99^+$ and Salmonella, respectively, and 50 oocysts for Cryptosporidium. The amplification efficiency of the multiplex PCR ranged between 0.97 and 0.99 for each pathogen. Among 97 samples, 36 samples were positive for at least one of the 6 major pathogens and 6 samples were simultaneously positive for 2 pathogens by the multiplex PCR assay. Coccidium oocysts were also detected in 48 samples, which were all collected from over 1 month old calves. In conclusion, the multiplex real-time PCR panel can be a useful tool for fast and accurate diagnosis of calf diarrhea associated with BVDV, BCoV, group A BRV, E. coli $K99^+$, Salmonella, and/or Cryptosporidium and Coccidium may be an important target which needs to be included in the multiplex PCR panel in the future.

• Korean Journal of Veterinary Service
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• v.46 no.1
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• pp.47-58
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• 2023

Between February 2020 and September 2021, 378 calves with diarrhea were investigated across 96 cattle breeding farms in Korea, using a rapid diagnostic kit. The study examined the infection rates of major pathogens causing diarrhea in calves, which were categorized by season, age, birth month, and region. Additionally, logistic regression analysis was conducted to investigate the factors affecting the infection rate. The study found that the five representative pathogens causing calf diarrhea exhibited differences in infection rates based on season, region, age, and birth month. Bovine rotavirus, bovine coronavirus, Cryptosporidium, and Giardia commonly exhibited varying risks of infection based on season and age. Furthermore, in addition to these risk factors, bovine rotavirus and Cryptosporidium were found to impact the infection risk of each pathogen by region, while Giardia was found to be affected by birth month.

• Korean Journal of Veterinary Service
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• v.43 no.3
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• pp.113-128
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• 2020

For estimating the prevalence of bovine infectious disease agents, the pathogens were classified as follows: the digestive disease agents, respiratory disease agents, reproductive disease agents, and tick-borne disease agents. This study covered 81 published papers regarding bovine infectious diseases in Korea that determined the presence of diverse pathogens or the antibodies elicited by the infectious agents in cattle from 2010 to 2019. In total, 59,504 cows were involved in the papers reporting the causative agents in their cases. The disease prevalence for the digestive, respiratory, reproductive, and tick-borne cases was 9.0%, 13.4%, 10.4%, and 7.8%, respectively. Bovine viral diarrhea virus, Escherichia coli, Mycobacterium avium subsp. paratuberculosis, and Eimeria spp were more significantly prevalent in the cows under one-year age than over one-year age. Bovine viral diarrhea virus, Escherichia coli, Mycobacterium avium subsp. paratuberculosis, and Anaplasma spp. were more significantly prevalent in Hanwoo than dairy cattle. Coxiella burnetii, Neospora caninum, and Theilieria spp. were more significantly prevalent in dairy cattle than Hanwoo. Tick-borne disease agents were more prevalent in cows grazing than the case in housing. Our analytic data obtained from this study emphasize the need for more studies on the occurrence of these pathogens according to the breed, age, and the region, to come up with bovine infectious disease control measures in Korea.