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1.
AIM: To estimate the incidence of clinical mastitis and the frequency of isolation of mastitis-causing organisms from clinical cases in one lactation season (July 2005 to May 2006) on 14 dairy farms from the Northland region of New Zealand.

METHODS: Cases of clinical mastitis were determined by trained farm personnel who recorded the identity of affected cows. Pooled milk samples from affected quarter(s) were aseptically collected by the farm personnel, for microbiology. Mean numbers of affected cows and quarters were compared at the population and farm level per 305 cow-days-at-risk (DAR).

RESULTS: One or more cases of clinical mastitis occurred in 559/3,765 (14.8%) lactating cows. The average incidence of clinical mastitis was 0.19 cases per 305 DAR. The incidence in rear quarters (56.2%) was 1.3 times (p=0.027) that of front quarters (43.8%). The incidence of clinical mastitis and numbers of affected quarters were signifi cantly infl uenced by the stage of lactation (higher in early lactation), age (higher in older cows) and farm. At the cow level, the most common isolates were Staphylococcus aureus (23.7%) and Streptococcus uberis (23.3%). No causative organisms were identifi ed in 19.9% of the samples. Each cow had an average of 1.8 quarters affected during a case of clinical mastitis.

CONCLUSIONS: This study demonstrated a higher incidence of staphylococcal clinical mastitis on dairy farms from Northland than has been reported in other regions of New Zealand.  相似文献   

2.
Biofilm formation and antimicrobial resistance of Staphylococcus aureus are important virulence factors in cases of mastitis in dairy cows. However, few studies have investigated mastitis strains isolated from heifers. Within this context, the objective of the present study was to investigate biofilm formation on Congo red agar, the presence of the icaA and icaD genes by polymerase chain reaction (PCR), and the percentage of in vitro antimicrobial resistance of 110 S. aureus isolates from mammary gland secretions of heifers and cows with mastitis. PCR detected the icaA and icaD genes in 98% and 100% of isolates, respectively. However, only 55.5% of all isolates produced a biofilm on Congo red agar. Antimicrobial susceptibility testing revealed that 47.0% of isolates from heifers and 70.4% of isolates from cows were resistant to at least one of the antimicrobial agents tested. Resistance to penicillin and/or ampicillin was the most frequent (44.5%). These results indicate the need to implement prophylactic and control measures of mastitis for heifers. Heifers and cows can carry resistant strains with the capacity of biofilm production, a fact representing a threat to public health and animal well‐being and generating losses to dairy farmers.  相似文献   

3.
The study was undertaken to determine the aetiology and prevalence of mastitis in hand-milked cows (n = 186) in two major Ethiopian dairies. The California Mastitis Test and culturing for bacteria revealed that 21.5% of the cows were clinically infected and 38.2% had subclinical mastitis. Most mastitis pathogens isolated from milk samples testing positive by the California Mastitis Test were Gram-positive cocci. Staphylococci constituted 57% of the isolates, of which the predominant cause of bovine mastitis was Staphylococcus aureus (40.5%). Other mastitis pathogens isolated include streptococci (16.5%), coliforms (9%) and corynebacteria (5%). Retrospective analysis of farm records indicated that mastitis was the second most important cause of culling and accounted for 27% of the cows removed from these two dairies.  相似文献   

4.
The objective of this study was to analyse the occurrence of methicillin‐resistant Staphylococcus aureus (MRSA) in three dairy herds in the southwest of Germany that had experienced individual cases of clinical and subclinical mastitis associated with MRSA. The herds were identified by the detection of MRSA during routine resistance testing of mastitis pathogens. All quarters of all cows in the herds that were positive on California Mastitis Test were sampled for bacteriological analysis on two occasions. Bulk tank milk samples were also tested. Furthermore, nasal swabs were collected from people working on the farms and from cattle. Environmental samples were collected from associated pig holdings. Isolates were characterized using spa‐typing and testing for antimicrobial resistance. Our results revealed a substantial spread of MRSA in the three dairy herds. In the first of the two investigations carried out on all cows in the three herds, milk samples of 5.1–16.7% of dairy cows were found positive for MRSA. The respective proportions in the second herd level investigation were 1.4–10.0%. Quarters harbouring MRSA had higher somatic cell counts than quarters that were negative on culture. Methicillin‐resistant Staphylococcus aureus were also detected in nasal swabs of staff (7/9), cows (7/15) and calves (4/7), bulk tank milk samples (3/3) and environmental samples from pig premises (4/5) on the farm. Herds B and C had no contact to herd A. However, in all three herds MRSA of spa‐type t011 were detected in milk samples. Results show that MRSA of spa‐type t011 is a problem in dairy farms that needs urgent attention.  相似文献   

5.
Infectious bovine mastitis is responsible for serious economic losses in dairy cattle breeding. Information about the damages caused by micro-organisms is of great interest and importance. The purpose of the present study was to report on the microbiological and histopathological aspects of the mammary parenchymas of slaughtered dairy cows. A total of 184 mammary glands were examined and samples of mammary parenchyma were collected for microbiological and histopathological examinations. Micro-organisms were isolated from 69.6% samples; 23 (12.5%) of the 184 samples did not show histological changes; inflammatory response was observed in 56 (30.4%) samples; inflammatory response and repair were present in 82 (44.6%) samples; repair process was verified in 23 (12.5%) of the mammary glands. Coagulase-negative Staphylococci were observed in 53.8% of the samples followed by coagulase-positive Staphylococci (7.6%), Prototheca sp. (2.2%) and Streptococcus dysgalactiae (1.6%). Coagulase-negative Staphylococci and coagulase-positive Staphylococci were associated mainly to chronic inflammatory response and chronic inflammatory response and repair. Samples from which no micro-organisms were isolated (n = 56) had no histological changes in 82.6% of the cases. These results were higher (P < 0.05) when compared to the samples with micro-organisms and without histological changes (17.4%).  相似文献   

6.
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7.
Dairy cow mastitis is a detrimental factor in milk quality and food safety. Mastitis generally refers to inflammation caused by infection by pathogenic microorganisms. Our studies in recent years have revealed the role of miRNA regulation in Staphylococcus aureus‐induced mastitis. In the present study, we overexpressed and suppressed miR‐145 to investigate the function of miR‐145 in Mac‐T cells. Flow cytometry, ELISA and EdU staining were used to detect changes in the secretion of several Mac‐T cytokines and in cell proliferation. We found that overexpression of miR‐145 in Mac‐T cells significantly reduced the secretion of IL‐12 and TNF‐α, but increased the secretion of IFN‐γ; the proliferation of bovine mammary epithelial cells was also inhibited. Using quantitative real‐time PCR (qRT‐PCR), Western blotting and luciferase multiplex verification techniques, we found that miR‐145 targeted and regulated FSCN1. Knock‐down of FSCN1 significantly increased the secretion of IL‐12, while the secretion of TNF‐α was significantly downregulated in Mac‐T cells. Upon S. aureus infection of mammary gland tissue, the body initiated inflammatory responses; Bta‐miR‐145 expression was downregulated, which reduced the inhibitory effect on the FSCN1 gene; and upregulation of FSCN1 expression promoted mammary epithelial cell proliferation to allow the recovery of damaged tissue. The results of the present study will aid in understanding the immune mechanism opposing S. aureus infection in dairy cows and will provide a laboratory research basis for the prevention and treatment of mastitis.  相似文献   

8.
AIM: To identify and enumerate colony forming units (cfu) of mastitis pathogens in bulk tank milk (BTM) from pasture-fed New Zealand dairy cows in the Waikato region.

METHODS: BTM samples from seven seasonal-calving dairy herds in the Waikato region were collected monthly from August to December 2004 (cows calved during July-September). Milk samples were cultured on blood aesculin and MacConkey agar plates for 24 h, and the number of mastitis pathogens identified and counted.

RESULTS: Colonies identified in BTM included aesculinpositive streptococci, Staphylococcus aureus, coagulase-negative staphylococci (CNS), and coliforms; counts ranged from zero to >1,000 cfu/ml. Counts >1,000 cfu/ml for total aesculin-positive streptococci, CNS and coliforms were present in 48%, 51% and 11% of BTM samples, respectively. Counts of Staph. aureus ranged from zero to 1,000 cfu/ml, but first appeared in BTM samples only in October. Staphylococcus aureus was repeatedly isolated in BTM from 4/7 farms during the testing period.

CONCLUSIONS: Counts of mastitis pathogens in this study appeared high relative to interpretive criteria set by other workers, which may indicate a high prevalence of mastitis risk factors on these farms. Interpretation of results is difficult as aesculinpositive streptococci, CNS and coliforms can be isolated from the environment as well as from cows with clinical or subclinical mastitis. Furthermore, Staph. aureus is inconsistently excreted from infected bovine mammary glands. More extensive study of this method is required in New Zealand to attempt to further validate the interpretation of results of bacterial culture of BTM.

CLINICAL RELEVANCE: This method may be used to monitor challenge from mastitis pathogens over time as part of milk quality control programmes. The technique may be of use as a screening test to provide information to veterinarians, affording them the opportunity to have an input into mastitis control on dairy farms in New Zealand.  相似文献   

9.
Bovine Mastitis in Selected Areas of Southern Ethiopia   总被引：3，自引：0，他引：3  
A study on bovine mastitis, designed to determine the causal agents, prevalence of infection and impact of risk factors in three cattle breeds, was conducted in selected areas of southern Ethiopia. A total of 307 lactating and non-lactating cows, of which 162 were indigenous Zebu, 85 Jersey and 60 Holstein-Friesian, were examined by clinical examination and the California mastitis (CMT) test. Of these, 40.4% were positive by CMT and bacteriology for clinical or subclinical mastitis, with prevalence rates of 37.1% and 62.9%, respectively. Out of 1133 quarters examined, 212 (18.7%) were found to be infected, 83 (39.2%) clinically and 129 (60.8%) subclinically. The prevalence of mastitis was significantly higher in Holstein-Friesian than in indigenous Zebu, in non-lactating cows than in lactating cows, in the early lactation stage than in the mid-lactation stage, in cows with lesions and/or tick infestation on skin of udder and/or teats than in cows without this factor, and in the wet season than in the dry season. Mastitis increased with parity number (R = 0.9). Of 248 CMT and clinically positive udder quarter samples analysed microbiologically, 212 were culturally positive for known mastitis pathogens and 36 were negative. Of the 199 positive samples, Staphylococcus accounted for 39.2%, Streptococcus for 23.6%, coliforms for 14.1%, Micrococcus and Bacillus species for 8.0% each and Actinomyces or Arcanobacterium (Corynebacterium) for 7.0%. It was concluded that there was a high prevalence of clinical and subclinical mastitis, mainly caused by Staphylococcus aureus, Streptococcus agalactiae and Escherichia coli, in this study area.  相似文献   

10.
The objective of the study was to estimate the prevalence and losses associated with subclinical mastitis (SCM) caused by Staphylococcus aureus in Ethiopian crossbred dairy cows. A split-udder trial was carried out to determine milk yield losses in udder quarter with S. aureus-caused SCM. Each quarter of the study cows was examined using the California Mastitis Test (CMT) and quarter milk production was measured over a period of 8 days. Milk yield losses for CMT positive quarters were estimated by comparing production of quarters with CMT score 0. Mean milk yield for uninfected healthy quarters was 1.66 kg per milking (95% CI, 1.66–1.55 kg per milking), and the rate of milk reduction for quarters with CMT scores of 1+, 2+, and 3+ was 25%, 33%, and 48%, respectively. Economic losses at different farm-size levels were calculated by multiplying the prevalence of CMT scores with milk yield losses associated with respective CMT scores. In Debre Ziet dairy herds, a quarter with SCM due to S. aureus lost an average of 34.5% of its potential milk production while the total milk yield loss per cow was estimated at 6.8%. Losses were highest in large-scale (13%) farms and lowest (3.7%) in small-scale. Based on the prevalence, the overall financial loss for each cow per lactation was 984.64 Eth Birr (US78.65) and losses in large farms (1,882.40 Eth Birr or US78.65) and losses in large farms (1,882.40 Eth Birr or US150.35) were over 3.5 times the loss in small-size farms. These figures possibly underestimate the potential benefits of mastitis control program as they do not include other direct and indirect costs.  相似文献   

11.
Two dry-cow therapy products were evaluated in seven factory-supply dairy herds in the Waikato area. A product containing neomycin sulphate and the benzathine salt of penicillin (Neopen D.C. White; Smith-Biolab) was used in five herds, and one containing benzathine cloxacillin (Orbenin, Beecham) was used in two herds. Non-treated control cows were included in each herd. Both products were effective in eliminating intramammary infections with Staphylococcus aureus, Streptococcus uberis, and Streptococcus agalactiae. Efficacy of dry-cow therapy against S. aureus was 83.8% and 85.2% respectively. Spontaneous cure rate among controls was 30.8% for S. aureus during the dry period. Spontaneous cure rate for Str. uberis was 50%, while dry-cow therapy eliminated 100% and 77.8%, respectively, for the two products. Dry-cow therapy with either product eliminated more than 90% of Str. agalactiae infections while spontaneous cure rate was only 28.6%. These results further support the effectiveness of dry-cow therapy in reducing the level of subclinical mastitis in dairy herds by shortening the duration of intramammary infections.  相似文献   

12.
A cross-sectional study was conducted between January and July 2014 in Unguja island of Zanzibar to establish prevalence of subclinical mastitis (SCM) in smallholder dairy cows and patterns of antibacterial susceptibility of major mastitis pathogens isolated. A total of 416 dairy cows from 201 farmers were randomly selected from three districts of Unguja Island to participate in the study. Questionnaire interview, field observation, individual cow examination, California Mastitis Test (CMT) and bacteriological examination were carried out. Kirby-Bauer disc diffusion technique was used to test drug sensitivity for common bacteria isolated. Based on CMT results, the overall prevalence of SCM was 28.6, 48.8 and 64.7% at quarter, cow and farm level, respectively. Prevalence of bacterial infection was recorded at 42.9, 70.9 and 78.6% at quarter, cow and farm examined, respectively. The common bacteria isolated included Staphylococcus aureus (36.8%), Pseudomonas aeruginosa (17.8%), Staphylococcus epidermidis (16.1%), Klebsiella spp. (9.5%), Micrococcus spp. (6.3%) and Escherichia coli (4.9%). In conclusion, findings of this study demonstrated high level of subclinical mastitis at farms, cows and quarters levels with both contagious and environmental bacterial pathogen involved. Therefore, efforts should be directed to the decreased subclinical mastitis by improving sanitary measures and proper milking practice.  相似文献   

13.
This study was conducted to evaluate alterations in coagulation parameters in dairy cows affected with acute Escherichia coli (E. coli) mastitis and to compare those values to cows affected with Staphylococcus aureus (S. aureus ) mastitis. Twenty-four, adult Holstein-Friesian dairy cows affected with acute E. coli mastitis and 17 cows affected with S. aureus mastitis were studied. Cows affected with E. coli mastitis had significantly prolonged activated partial thromboplastin time (APTT) (P < 0.01), prothrombin time (PT) (P < 0.05) and decreased (P < 0.05) platelets numbers. Cows with S. aureus mastitis had only significantly prolonged APTT (P < 0.05) and decreased (P < 0.05) platelet counts. In the hematology evaluation, cows affected with E. coli and those affected with S. aureus mastitis had elevated hematocrit values but only significantly (P < 0.05) so in mastitic cows caused by E. coli. Both groups of mastitic cows had significantly (P < 0.05) lower leukocyte counts. Only cows with E. coli mastitis had significantly (P < 0.05) lower neutrophil count. In the plasma biochemical evaluation, creatinine concentrations were significantly (P < 0.05) elevated in both groups of cows. Blood urea nitrogen (BUN) concentration was only significantly elevated in cows affected with E. coli mastitis. Results of this study indicated that dairy cows affected with acute E. coli mastitis are more likely to develop clinical manifestations of disseminated intravascular coagulation than cows affected with S. aureus mastitis.  相似文献   

14.
A SURVEY OF CLINICAL MASTITIS IN SOUTH-EAST QUEENSLAND DAIRY HERDS   总被引：2，自引：0，他引：2  
SUMMARY A survey of clinical mastitis in 26 South-East Queensland dairy herds supplying more than 300,000 litres of milk annually, revealed a quarter incidence of 2.6% with a cow incidence of 9% over a 3-month period. Secretion samples from cows yielded Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, coliforms, Pseudomonas spp and other bacteria in 38.5%, 12.5%, 6.6%, 3.4%, 2.6%. 0.6% and 2.0% of cases respectively. Samples from 38% of the cases were culturally negative while at least 38% of the clinical quarters had shown a previous clinical episode of mastitis. There was a significant association (P < 0.025) between herd and the likelihood of a negative culture result on samples from clinical cases. Twenty-one percent of cases occurred in the first month of lactation and 10.3% in the first week. There was a significant association (P < 0.005) between the age of cow and the stage of lactation in which clinical cases occurred in that cows in the 2 to 5 year age group were more likely to suffer attacks in the earlier part of lactation. There was a highly significant relationship (P < 0.005) between cow age group and the proportion of affected quarters and it was calculated that the change with each year of age was a 55% increase over the previous year. Forty-five percent of the isolates of S. aureus were resistant to penicillin.  相似文献   

15.
The German wasp, Vespula germanica has been observed to injure teats of dairy cows, causing lesions that are associated with clinical and subclinical mastitis. The presence of skin lesions on the teats, caused by the wasps, was recorded in a dairy cattle herd located in the Samaria foothills during July–October 1999. Wasp‐inflicted injuries were found in 43.6% (58 of 133) of the adult cows and 1.4% (one of 71) of the first‐calving cows. They were located in 42.4% of cows (n = 25) on all quarters, 18 cows (30.5%) had lesions on the front quarters and 27.1% (n = 16) of cows on the hind quarters only. Clinical and subclinical mastitis were diagnosed in 61% (36 of 59) and 28.8% (17 of 59), respectively, of the injured adult and first‐calving cows. The most common bacterial isolates from the mastitic cows were Staphylococcus aureus 45.1% (n = 14), Streptococcus dysgalactiae 16.1% (n = 5), Streptococcus spp. 19.4% (n = 7) and others 13.9% (n = 5). The loss of milk production was estimated at 300 kg milk for each cow injured by wasps and exhibiting clinical mastitis. An increase in the bulk‐milk somatic cell count, from 186 × 103 at 1 month prior to the outbreak to a peak of 1200 × 103 in the post‐outbreak month, was noted. The culling rate reached 13.6% (eight of 59) of the affected cows. In summary, the considerable economic losses caused by the wasp infestation resulted from decreased milk production and a decline in milk quality, culling of affected cows, and increased demand for use of drugs and veterinary care.  相似文献   

16.
Objective To determine the prevalence of mastitis pathogens in high‐producing intensive dairy herds in New South Wales. Design Field survey. Procedure Milk samples from the mastitis‐affected quarter were collected from cows on five high‐producing dairy farms in NSW. The 820 samples were cultured using standard microbiological culture techniques. Results Bacteria or fungi were isolated from 83.3% of samples (683/820). More than two colony types were isolated from 16.7% of samples (137/820), two types from 6.6% (54/820), and one type from 52.3% (429/820). No bacteria were isolated from 24.4% (200/820) of the primary cultures, but enrichment cultures of these samples yielded single colony type bacterial isolates from 36.5% (73/200) of samples. Environmental pathogens, including coliforms, environmental Streptococcus and Staphylococcus spp., made up 91% (555/610) of isolates and accounted for 33.6% (205/610), 41.6% (254/610) and 15.7% (96/610), respectively, of isolates. Escherichia coli accounted for 76.1% (156/205) of the coliform isolates, Streptococcus uberis and Streptococcus dysgalactiae accounted for 32.3% (82/254) and 28.0% (71/254), respectively, of the environmental streptococcal isolates. Contagious pathogens were uncommon, comprising only 2.5% (15/610) of the total isolates. Conclusion The incidence and causes of mastitis are largely influenced by farm management. The relatively high prevalence of coliform mastitis in the intensive high‐producing herds in this survey contrasts with the low incidence reported in surveys of pasture‐based herds in Victoria. If the Australian dairy industry continues its current trend of intensification, coliform intra‐mammary infections may emerge as an increasingly important cause of mastitis.  相似文献   

17.
Mastitis caused by the colourless alga Prototheca zopfii was diagnosed in 17 of 120 cows in a dairy herd. Infection occurred in animals varying from 3–14 years old and was present in one to four quarters of each cow.

Nine cases were associated with clinical mastitis characterised by the presence in milk of flakes or small clots. Somatic cell counts consistent with subclinical mastitis (>500 × 103 cells/ml) were recorded in five of the eight remaining cows.

Histological examination of udder tissue showed the presence of granulomatous lesions associated with the presence of Prototheca.

The problem was identified and controlled by repeated microbiological examination of milk samples from all lactating cows and immediate culling of infected animals.

P. zopfii was also recovered from environmental water samples on this farm. It is suggested that infection may have occurred as a result of teat sores caused by trauma from a milking machine, and the tendency for cows to lay down on a race, the surface of which was sometimes flooded by drain water in which Prototheca were present.  相似文献   

18.
Mastitis caused by Prototheca spp or Nocardia spp is considered to be difficult to treat. Both microorganisms are contaminants commonly found in soil. The occurrence of mastitis caused by these agents was studied in a particular dairy farm. In this herd, the animals were kept at pasture overnight and during daytime were brought to a pen where they were fed. This pen accumulated mud and faeces, particularly in the rainy season. During milking, pre-dipping of the teats was performed with an iodide solution, but they were not washed, so a layer of soil and faeces remained which may have contaminated the milking equipment. The herd comprised 91 lactating animals and 47 dry cows. For microbiological examination, 107 milk samples were collected from lactating cows and 186 samples of mammary secretions from the dry cows. Prototheca spp were isolated from 14.55% of the milk samples and Nocardia spp from 4.55%. Prototheca spp were isolated from 8.06% of the secretion samples from dry cows and Nocardia spp were isolated from 2.15% samples. The high occurrence of mastitis due to these environmental agents reflects the problem of keeping animals in muddy pastures and pens, and the defective pre-milking hygiene for the teats.  相似文献   

19.
Diagnostic strategies to detect contagious mastitis caused by Mycoplasma bovis, Staphylococcus aureus, and Streptococcus agalactiae in dairy herds during an outbreak have been minimally studied with regard to cost and diagnostic sensitivity. The objective of this cross-sectional study was to compare the cost-effectiveness of diagnostic strategies for identification of infected cows in two California dairy herds during contagious mastitis outbreaks.  相似文献   

20.
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