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1.
Quarter milk samples (n = 543) from 152 traditionally managed lactating camels (Camelus dromedarius) in Afar Region, north-eastern Ethiopia were examined to determine the prevalence of camel mastitis and identify its bacterial causes. Out of 152 camels examined, 19 (12.5%) were diagnosed as clinical mastitis cases based on clinical signs and bacteriological examinations. Of the 257 California Mastitis Test (CMT) positive quarter milk samples 162 (63.0%) yielded pathogenic bacteria. A positive correlation was observed between CMT positive results and presence of major pathogens in camel milk samples. The main mastitis pathogens isolated were Staphylococcus aureus, coagulase-negative staphylococci, Streptococcus agalactiae, S. dysgalactiae, and other species of streptococci, Pasteurella haemolytica and E. coli. Results of the present study suggest that mastitis in Afar camels is prevalent, Gram-positive cocci are the major isolates from camel milk samples and the CMT can be used as a screening test for the detection of mastitis in camels.  相似文献   

2.
Quarter milk samples (n = 391) from 101 camels were examined to study the occurrence and causes of mastitis in traditionally managed camels in eastern Sudan and to evaluate the value of the California Mastitis Test (CMT), somatic cell count (SCC) and adenosine triphosphate (ATP) in the detection of subclinical mastitis in the camel.One hundred and seventy (43.5%) of the quarter milk samples yielded pathogenic bacteria. Streptococcus agalactiae, other Streptococcus spp., Staphylococcus aureus, coag–ulase–negative staphylococci, and Escherichia coli were isolated from milk. Thirty–two (8.2%) quarter milk samples yielded mixed cultures, and 189 (48.3%) yielded no growth.Mean values for CMT, SCC and ATP were higher for quarters infected with major pathogens. However, a significant number of quarter milk samples had elevated values in these tests but were from quarters from which no bacteria were isolated. The ability of the tests to predict a positive bacteriology increased slightly when 2 or 3 tests were combined. kw|Keywords|k]inflammation; k]diagnostic tests; k]Mastitis; k]CMT; k]ATP; k]bacteriology; k]Sudan  相似文献   

3.
The relationship between somatic cell counts (SCC) and California mastitis test (CMT) results according to the infectious status of mammary halves and parity of Pampinta dairy ewes was evaluated. Tests were associated to bacteriological analysis and classified into three groups: uninfected (negative culture), infected by minor pathogens and infected by major pathogens. Coagulase-negative Staphylococcus (32.4%), Micrococcus spp. (32.4%), Corynebacterium spp. (5.4%), and Bacillus spp. (1.4%) were the minor pathogens isolated, while Staphylococcus aureus (27%) and Escherichia coli (1.4%) were the major pathogens isolated. A good correlation was found between the CMT and SCC, which included inflammatory and epithelial cells (r = 0.64; P < 0.0001). SCC averages for the CMT scores shown in parentheses were 223 576 (0); 245,248 (1); 397,778 (2); 1,159,109 (3) and 2,460,833 (4) cells/ml. The correlation between SCC and the infectious status of udder halves was 0.58 (P < 0.0001). The relationship between SCC and CMT profiles and infectious status studied by a discriminant analysis showed, with an accuracy of 65%, three infectious status groups. SCC arithmetic means were 244,470 cells/ml for negative culture, 1,044,100 cells/ml for minor pathogens and 2,045,652 cells/ ml for major pathogens. With the exception of 1-year-old ewes, no significant differences were observed in SCC as affected by age or parity.  相似文献   

4.
Spring-calving multiparous Angus x Hereford cows were used to determine the efficacy of intramuscular treatment with oxytetracycline to reduce the incidence of mastitis-causing bacteria, decrease milk somatic cell counts (SCC), and increase calf growth. During 2 yr, milk samples were collected from each quarter from a total of 319 cows at 8 to 14 d after calving and at weaning, to determine the presence of bacteria and SCC. A California mastitis test (CMT) was performed on milk from each quarter of each cow at the initial sample collection. Cows with a CMT score of 1, 2, or 3 in at least one quarter, were randomly assigned to receive either an intramuscular injection of oxytetracycline (n = 63) or the control vehicle (n = 60), and cows with a CMT score of 0 or trace in all four quarters were not treated (n = 196). Calf weights were determined at birth, early lactation, and weaning. The number of somatic cells in milk and the percentage of quarters that were infected increased as CMT score increased (P < 0.01). The presence of mastitis-causing bacteria at calving increased (P < 0.05) the incidence of infection at weaning. The presence of mastitis-causing bacteria at weaning was associated with increased SCC for quarters and average SCC for cows (P < 0.01). Average SCC per cow at weaning increased (P < 0.05) as the number of infected quarters per cow increased. Treatment did not alter (P > 0.10) the percentage of cows or quarters infected with mastitis-causing bacteria or SCC of cows or quarters at weaning. Average SCC per cow was negatively correlated (P < 0.05) with calf weights at early lactation, but not with weaning weights of calves. Treatment did not influence (P > 0.10) calf weights at early lactation or at weaning. Cows with one or more dry quarters after calving had calves that weighed less at early lactation and weaning than cows with four functional quarters (P < 0.01). Intramuscular oxytetracycline treatment of beef cows that had CMT scores of 1 or greater after calving did not reduce intramammary infection rates or increase calf weights at weaning.  相似文献   

5.
The aim of the study was to determine the diagnostic value of measuring serum amyloid A (SAA) concentrations in milk of individual ewes and in farm bulk milk for monitoring udder health. Udder health was calculated by examining a randomly selected group of seven flocks at each farm visit by means of California mastitis test and bacteriological examination of 5749 milk samples. SAA was determined additionally in 267 randomly selected milk samples from six flocks. Thirty-one bulk milk samples from these farms were tested for SCC and SAA levels. Subclinical infections were detected in 29.5% of samples whereas no clinical infections were observed. Intramammary infected udder halves showed significantly elevated SAA concentrations (121.3+/-25.3 microg/ml) in milk compared to the levels of healthy udder halves (8.0+/-1.9 microg/ml; p<0.001). SAA was significantly elevated in sheep with elevated CMT scores and positive bacteriological results. Bulk milk SAA levels ranged from 18.6+/-6.7 to 37.4+/-14.1 microg/ml and showed a positive correlation with bSCC (r=0.38, p=0.018) but not with percent infected glands (r=0.022, p=0.453). This study demonstrated that SAA levels in milk can be used to detect subclinical mastitis in individual ewes whereas further investigations are needed to determine the value of measuring SAA in bulk milk for monitoring flock udder health.  相似文献   

6.
This study was conducted to investigate the normal somatic cell count (SCC) and to define subclinical mastitis in Murrah buffaloes. Data were collected from 60 clinically normal buffaloes stationed at five farms of Chitwan Nepal and Buffalo Research Center, Hissar, India. Somatic cell count was measured using the Newman-Lampert staining technique. The upper limit of SCC was determined >or=200 000/ml of milk based on the mean +/- 2SD of a total SCC. Abnormal data of the SCC was repeatedly removed, which lie beyond the values of more than mean + 2SD until all the data come to lie within (mean + 2SD). Averages of SCC of right front and right hind quarters were significantly higher than left front and left hind quarters. Nearly 94% of California mastitis test (CMT) negative quarters were having somatic cells >or=200 000/ml. The mean SCC of CMT positive quarter was significantly higher (P < 0.01) than CMT negative quarters. Subclinical mastitis was diagnosed on the basis of samples with SCCs >or=200 000/ml with positive bacterial cultures. Subclinical mastitis was found in 21.7% buffaloes and 8% of the quarter foremilk samples. Neutrophil counts were significantly higher in subclinical mastitis milk.  相似文献   

7.
Quarter foremilk samples were taken at 2–3 weekly intervals for several years in a experimental herd comprising about 45 cows. The samples were submitted to bacteriological analysis and somatic cell counting. The most prevalent quarter infections from 1982 to 1988 were by coagulase-negative staphylococci (15–20% of all the quarters sampled). Most of these (75.6%) persisted until drying-off Dry cow therapy eliminated 86.5% of these infections. Comparison of udder quarters within cows, involving 775 samples from pairs of non-infected quarters and quarters infected by coagulase-negative staphylococci, yielded geometric means of somatic cell counts of 210 000 and 420 000 cells/ml, respectively. The correlation (r=0.87) between the herd bulk milk somatic cell count (SCC) and its estimation from the quarter milk somatic cell count performed on the same day allowed us to evaluate the contribution of the different categories of quarters, according to their infection status, to the herd bulk milk SCC. Quarters infected by a major pathogen (8.5% of samples) gave rise to 46.6% of the total number of cells, while quarters infected by coagulase-negative staphylococci (17.8% of samples) gave rise to 18.1%. Although coagulase-negative staphylococci represented only a secondary source of somatic cells as compared to major pathogens, they were not a negligible source considering the threshold of 300 000 somatic cells advocated for herd milk of good quality.  相似文献   

8.

Background

Mastitis is the most important and costly disease in dairy goat production. Subclinical mastitis is common in goats and is mainly caused by contagious bacteria. Several methods to diagnose subclinical mastitis are available. In this study indirect measurement of somatic cell count (SCC) by California Mastitis Test (CMT) and direct measurement of SCC using a portable deLaval cell counter (DCC) are evaluated. Swedish goat farmers would primarily benefit from diagnostic methods that can be used at the farm. The purpose of the study was to evaluate SCC measured by CMT and DCC as possible markers for intramammary infection (IMI) in goats without clinical symptoms of mastitis. Moreover to see how well indirect measurement of SCC (CMT) corresponded to direct measurement of SCC (DCC).

Method

Udder half milk samples were collected once from dairy goats (n = 111), in five different farms in Northern and Central Sweden. Only clinically healthy animals were included in the study. All goats were in mid to late lactation at sampling. Milk samples were analyzed for SCC by CMT and DCC at the farm, and for bacterial growth at the laboratory.

Results

Intramammary infection, defined as growth of udder pathogens, was found in 39 (18%) of the milk samples. No growth was found in 180 (81%) samples while 3 (1%) samples were contaminated. The most frequently isolated bacterial species was coagulase negative staphylococci (CNS) (72% of all isolates), followed by Staphylococcus aureus (23% of all isolates). Somatic cell count measured by DCC was strongly (p = 0.000) associated with bacterial growth. There was also a very strong association between CMT and bacterial growth. CMT 1 was associated with freedom of IMI while CMT ≥2 was associated with IMI. Indirect measurement of SCC by CMT was well correlated with SCC measured by DCC.

Conclusions

According to the results, SCC measured with CMT or DCC can predict udder infection in goats, and CMT can be used as a predictor of the SCC.  相似文献   

9.

Purpose  

To evaluate a 3% solution of household detergent viz., Surf Excel (Surf field mastitis test, SFMT) vis-à-vis California mastitis test (CMT), Whiteside test (WST), somatic cell counts (SCC; cut off limit = 5 × 105 cells per millilitre) and bacteriological cultures for the detection of subclinical mastitis in quarter foremilk samples (n = 800) of dairy cows and buffaloes.  相似文献   

10.
In a survey of about 3000 dairy cows producing low somatic cell count (SCC) milk and kept on a large-scale dairy farm, California Mastitis Test (CMT) positivity was found in 2714 udder quarters of 1491 cows. Pathogenic microorganisms were isolated from 57.6% of these 2714 udder quarters during bacteriological examination. The commonest pathogens were coagulase-negative staphylococci (CNS, 41%) and Staphylococcus aureus (32.5%); however, udder infections caused by environmental streptococci (12.8%) and coliform bacteria (6.8%) were also common. All pathogens resulted in a significant increase of the SCC in individual bulk milk (IBM) samples. In the case of CNS, this SCC elevation in IBM was significantly lower than in the case of infection by the other pathogens. In spite of this, because of the high number of udder infections caused by CNS, the adverse effect exerted by CNS on dairy herds is considered to be substantial. It was found that 54.6% of all CMT-positive cows produced IBM of an SCC below 400 thousand per ml. The milk produced by 41% of the 315 cows excreting S. aureus also had an SCC below 400 thousand per ml. This poses a serious risk of infection to the healthy herdmates. At the same time, 11% of the infected cows produced IBM with an SCC below 100 thousand per ml. On the basis of these findings, only the regular analysis of SCC of IBM can be a reliable indicator of chronic intramammary infection. As the SCC of milk produced by CMT-positive cows (and especially of those excreting pathogens) tended to increase with advancing lactation, the authors suggest that an efficient drying-off therapy should be used to restore udder health and, whenever justified, culling of cows cannot be avoided either.  相似文献   

11.
It was the objective of this study to analyse shedding patterns and somatic cell counts in cows and quarters infected with Prototheca spp. and to evaluate two approaches to identify infected animals by somatic cell count (SCC) or by bacteriological analysis of pooled milk samples. Five lactating dairy cows, chronically infected with Prototheca spp. in at least one quarter were studied over 11 weeks to 13 months. Quarter milk samples and a pooled milk sample from 4 quarters were collected aseptically from all quarters of the cows on a weekly basis. Culture results of quarter milk and pooled samples were compared using cross tabulation. SCC of quarter milk samples and of pooled samples were related to the probability of detection in the infected quarters and cows, respectively. Shedding of Prototheca spp. was continuous in 2 of 8 quarters. In the other quarters negative samples were obtained sporadically or over a longer period (1 quarter). Overall, Prototheca spp. were isolated from 83.6% of quarter milk samples and 77.0% of pooled milk samples of infected quarters and cows. Somatic cell counts were higher in those samples from infected quarters that contained the algae than in negative samples (p < 0.0001). The same applied for composite samples from infected cows. Positive samples had higher SCC than negative samples. However, Prototheca spp. were also isolated from quarter milk and pooled samples with physiological SCC (i.e. < 10(5)/ml). Infected quarters that were dried off did not develop acute mastitis. However, drying off had no effect on the infection, i.e. samples collected at calving or 8 weeks after dry off still contained Prototheca spp. Results indicate that pre-selection of cows to be sampled for Prototheca spp. by SCC and the use of composite samples are probably inadequate in attempts to eradicate the disease. However, due to intermittent shedding of the algae in some cows, single herd sampling using quarter milk samples probably also fails to detect all infected cases. Therefore, continuous monitoring of problem cows with clinical mastitis or increased SCC in herds during eradication programs is recommended.  相似文献   

12.
A study was carried out to establish the prevalence and determinants of mastitis and milk‐borne zoonoses in smallholder dairy farms in Kibaha and Morogoro districts (Tanzania). A total of 57 herds comprising 114 milking cows in Kibaha and 48 herds consisting of 96 milking animals in Morogoro were included in the study. A questionnaire survey was used to assess the socio‐economic determinants of mastitis, whereas California mastitis test (CMT) and microbiological assessment of milk was carried out to establish the status of mastitis and responsible aetiological agents. Seroconversion for brucellosis was evaluated using enzyme‐linked immunosorbent assay (ELISA). Animals were also tuberculin‐tested using a single comparative intradermal method and milk samples were cultured for isolation of Mycobacterium species. Based on CMT, the cow‐based prevalence of subclinical mastitis was 82.4% in Kibaha and 62.4% in Morogoro. Of the 919‐quarter milk samples cultured, 8.2% were positive for aerobic bacteria with predominant isolates being Staphylococcus epidermidis (2.8%), Staph. aureus (1.7%), Streptococcus agalactiae (1.2%) and Staph. intermedius (1.1%). There was a strong association between CMT positivity and bacteriological isolation [relative risk (RR) = 2.60; P = 0.02]. Fungal growth was observed in 21.8% (n = 881) of the samples and the isolates were yeast (19.2%), Mucor (2.5%) and Aspergillus (0.1%). Bucket feeding of calves was associated with increased risk of a quarter being CMT positive (RR = 1.24; P = 0.000), while residual calf suckling was associated with decreased risk of positivity (RR = 0.86; P = 0.015). Earth floor was associated with increased risk of CMT positivity at quarter level (RR = 1.13; P = 0.041) and Jersey breed was identified as a risk factor to mastitis. The prevalence of bovine tuberculosis was 0.4% (n = 259) and 1.7% (n = 181) in Kibaha and Morogoro, respectively. Similarly, the prevalence of brucellosis was 1% (n = 208) in Kibaha and 1.9% (n = 104) in Morogoro. Findings from this study have demonstrated a high prevalence of subclinical mastitis and existence of health risks to milk consumers despite the low prevalence of tuberculosis and brucellosis in the study herds.  相似文献   

13.
Detection of ovine intramammary infection with the California mastitis test   总被引：1，自引：0，他引：1  
The overall sensitivity of the California mastitis test (CMT) for detecting intramammary infection (the likelihood of a positive CMT score in the presence of intramammary infection) was 69.3%. The specificity of the CMT (likelihood of a negative test in the absence of intramammary infection) was 76.5%. When only infections by major ovine mastitis pathogens were considered, the sensitivity increased to 100% and the specificity decreased to 71.1%. Bacterial cultural examination and CMT scores were recorded for 526 samples of milk obtained from 106 brood ewes. Positive CMT scores were recorded for all samples from udder halves infected with major ovine mastitis pathogens (coagulase-positive staphylococci, Escherichia coli, and Pasteurella haemolytica). The CMT scores for samples from udder halves infected with coagulase-negative staphylococci were variable.  相似文献   

14.
对330个乳样分别用加州乳腺炎检验(California Mastitis Test,CMT),体细胞计数(Somatic Cell Count,SCC)和细菌的分离培养(Isolation of bacteria)法进行隐性乳腺炎的检测,结果表明3种方法检测的结果差异不显著(P>0.05);对检测患有隐性乳腺炎的241乳区进行了细菌的分离培养,结果表明引起隐性乳腺炎的最主要致病菌为金黄色葡萄球菌、凝固酶阴性葡萄球菌、链球菌、酵母菌、假单胞菌和棒状杆菌、其它细菌的检出率差异根显著(P<0.05)。对分离出优势细菌的部分乳样进行了SCC与LDH,NAGase,ALP和ACP几种酶的测定和相关性分析,结果表明:LDH与SCC有显著的相关性(r=0.7936),并且LDH与NA-Gase,ALP,ACP都有明显的相关性;NAGase与ACP,LDH有明显的相关性,但与ALP没有相关性;ALP只与ACP和LDH有显著的相关性外,与SCC,NAGase没有相关性;ACP与SCC,LDH,NAGase,ALP都有极显著的相关性。  相似文献   

15.
This study compared the different leucocyte populations in milk from udders infected with different mastitic pathogens and in different stages of infection. Milk samples were collected from quarters free of intramammary infection, acutely infected with Escherichia coli or Staphylococcus aureus and chronically infected with S. aureus, coagulase-negative staphylococci (CNS) or Streptococcus dysgalactiae. Udder bacteriological status was confirmed after three consecutive bacteriological examinations from weekly quarter milk samples. At the time of the trial, milk samples were tested for somatic cell count (SCC) and differential cell count by both light microscopy (LM) and flow cytometry. Monoclonal antibody (mAb) CD11a/CD18 was used in order to differentiate between leucocytes and epithelial cells when tested by flow cytometry. Udder quarters free of intramammary infection had a mean SCC lower than 107 x 10(3) cells/ml in which the epithelial cells were the main cell type followed by polymorphonuclear cells (PMNs), while macrophages and lymphocytes had a lower concentration. Only 56% of the cells were labelled with the mAb anti-CD11a/CD18. In either acute E. coli- or S. aureus-infected quarters, SCC were significantly higher (P < 0.0001) than in samples from the time of inoculation, with over 90% of the cells labelled with the mAb anti-CD11a/CD18. The main cell type was neutrophils. In chronically infected cows, differences in SCC and in leucocyte patterns were found between infecting pathogens as well as between quarters harbouring the same pathogen. In all the chronically infected quarters, SCC was significantly higher (P < 0.05) than in uninfected ones. The distribution of the leucocyte patterns in the quarters infected with S. dysgalactiae did not differ from that in quarters with acute infection with both E. coli and S. aureus. In the cows chronically infected with S. aureus or CNS, the proportion of PMN was higher but not significantly different from quarters free of intramammary infection, while epithelial cells were significantly lower (P < 0.05). The T lymphocytes bearing CD4+ or CD8+ were significantly higher in quarters chronically infected with S. aureus than in quarters free of intramammary infection and in quarters acutely infected with either E. coli or S. aureus. In all samples B cells were negligible.  相似文献   

16.
Milk samples (n=160) from 7 clinically healthy bactrian camels were cultured to detect subclinical udder infection. The samples were assessed by the Californian mastitis test (CMT) and somatic cell count (SCC). Bacteria were recovered from 36 (22.5%) of the milk samples. Staphylococcus aureus and coagulase-negative staphylococci (CNS) were the main organisms found.Infected quarters had significantly higher mean values for the SCC (p<0.01) and CMT (p<0.001) than non-infected quarters. All 7 camels were infected with CNS but only 4 with S. aureus. CMT values for S. aureus-infected camels were significantly higher than for those only infected with CNS. The values for SCC and CMT were significantly influenced by the stage of lactation (p<0.05). No significant difference was found from the effect of the quarters. Both SCC and CMT were of value in predicting the infection status of the udder.Abbreviations CMT California mastitis test - SCC somatic cell count - CNS coagulase-negative staphylococci  相似文献   

17.
Experimental intramammary infections were induced in five post-parturient Holstein cows by inoculation of low numbers (5000 colony forming units) of virulent Salmonella dublin via the teat canal of mammary gland quarters. Rectal temperature, pulse and respiratory rates, milk yield, and milk quality as assessed by the California Mastitis Test (CMT) and somatic cell counts (SCC) were recorded every 12 hours at milking. Bacteriologic cultures of foremilk quarter samples and feces were obtained daily, as were complete blood counts. ELISA titers for IgG and IgM recognizing S. dublin lipopolysaccharide (LPS) were obtained weekly on serum and quarter milk samples. All cows excreted S. dublin intermittently from infected quarters, but no changes were detected in rectal temperature, appearance of the mammary gland or secretions, CBC, milk yield, and pulse and respiratory rates. Somatic cell counts were modestly increased in infected quarters as compared with uninfected quarters (P = .015, paired t test); however, CMT scores after infection remained low, and were not significantly different from pre-infection scores (P greater than .10, sign test). After infection, administration of dexamethasone resulted in signs of clinical mastitis and increased excretion of S. dublin from mammary quarters (P = .0004, paired t test). One cow had necrotizing mastitis and S. dublin septicemia and was euthanatized. In the four surviving cows, clinical improvement was observed after systemic gentamicin therapy and intramammary infusion with polymyxin B, but all cows continued to excrete S. dublin intermittently from one or more quarters and occasionally from feces for the remaining period of observation. All infected cows demonstrated a rise in IgG and IgM ELISA titers recognizing S. dublin LPS in serum and milk. At necropsy (13-25 weeks postinfection), S. dublin was recovered only from the mammary tissue or supramammary lymph nodes in three of four cows. In one cow, mammary gland and lymph-node samples were negative for S. dublin despite positive milk cultures. In all cows, histopathologic examination revealed multifocal areas of chronic active mastitis. These lesions were similar to histopathologic findings from mammary gland carriers with naturally acquired S. dublin infection.  相似文献   

18.
Coagulase-negative Staphylococcus species (CNS) were isolated from 11.3% (1407 of 12,412) of mammary quarter milk samples obtained from cows in three dairy research herds in 2005. Approximately 27% (383/1407) of CNS was identified to the species level. The species distribution among those CNS identified from all herds was Staphylococcus chromogenes (48%), Staphylococcus hyicus (26%), Staphylococcus epidermidis (10%), Staphylococcus simulans (7%), Staphylococcus warneri (2%), Staphylococcus hominis (2%), Staphylococcus saprophyticus (1%), Staphylococcus xylosus (1%), Staphylococcus haemolyticus (<1%), Staphylococcus sciuri (<1%), and Staphylococcus intermedius (<1%). Staphylococcuschromogenes was the predominant CNS isolated from all three herds; however, differences were seen in the prevalence of other CNS species. A total of 158 CNS (S. chromogenesn=66, S. hyicusn=38, S. epidermidisn=37, S. simulans n=10, and S. warneri n=7) were analyzed by pulsed-field gel electrophoresis (PFGE). The majority (33/41) of CNS isolated from the same mammary quarter on more than one occasion had the same PFGE pattern indicating persistence of the same infection over time. When all PFGE patterns for each CNS were analyzed, no common pulsotype was seen among the three herds indicating that CNS are quite diverse. Composite milk somatic cell count (SCC) data were obtained +/-14d of when CNS were isolated. Average milk SCC (5.32 log(10)/ml) for cows in which CNS was the only bacteria isolated was significantly higher than the average milk SCC (4.90 log(10)/ml) from cows with quarter milk samples that were bacteriologically negative.  相似文献   

19.
A study was performed in 1997 to estimate the prevalence and to investigate the etiology of subclinical mastitis in Swiss dairy herds managed under guidelines of controlled organic farming. It was planned as a longitudinal study over a period of 1 year and included a stratified random sample of 152 certified organic farms and 1907 cows. Two farm visits (the first from June to October when cows were on pasture, the second from January to March when cows were confined to barns) were performed on each farm. At each visit, farm management and individual-cow data (with emphasis on milking procedures and udder sanitation) were recorded. California mastitis tests (CMTs) were performed on each udder quarter of all cows in lactation. Milk samples with CMT >1+ were submitted for somatic cell counting (SCC), bacteriological examination and to test for antibiotic susceptibility. The SCC and germ-cell counts of monthly bulk-tank milk samples were available through Dairy Inspection and Advisory Services and milk production data of 567 herd-book cows were available from breeding associations. Possible individual and environmental predictors of subclinical mastitis were identified using logistic models adjusted for clustering of the data at herd and cow levels. Data were analyzed separately for cows from 7 to 100 and from 101 to 305 days post partum. Prevalences of subclinical mastitis at the quarter level were 21.2% for lactation period 7–100 days and 34.5% for 101–305 days post partum. The geometric mean SCC in bulk-tank milk samples was 85.6×103 cells/ml. Samples at 7–100 and 101–305 days post partum were positive for Staphylococcus aureus in 16.0 and 7.4%, for coagulase-negative Staphylococci in 51.5 and 50.6%, for Streptococcus agalactiae in 0.0 and 0.8%, for other Streptococci in 19.4 and 15.6%, for E. coli in 1.0 and 0.4%, and for Corynebacterium bovis in 25.7 and 45.1%, respectively. Risks of subclinical mastitis increased significantly with increasing days post partum and advancing age of cow. Cows that were sampled when staying in alpine dairies had considerably higher risks of subclinical mastitis than cows staying in home barns. Significantly lower risks of subclinical mastitis were observed in farms where CMT was performed regularly as a control measure. Bacteria in milk from cows with mastitis exhibited antibiotic resistance at a comparable frequency as found previously in conventional farms.  相似文献   

20.
The aim of this study was to investigate the relationship between clinical findings and bacterial isolation in milk samples of meat-producing ewes. The study was conducted in 17 commercial flocks and 550 udder halves from suckling Santa Ines ewes. Initially, the clinical examination of the mammary glands and teats was performed by visual inspection and palpation of the teats and udder halves; then a scoring system was devised for all the findings. After that, the strip cup test and the California mastitis test (CMT) were performed. Then, milk samples for somatic cell counts (SCCs) and bacteriological analyses were collected. Staphylococci bacteria were the main etiological agent isolated in the present study. Upon investigation of the correlations between bacterial isolation and the clinical findings, only the presence of teat injury, pendulous udder, and alterations in the palpation of the teat were associated with bacterial isolation. A significant correlation between bacteriologically positive milk samples and CMT and SCC was also found. Thus, some clinical findings appeared as a risk factor for bacteriologically positive milk samples and can be used as a tool in mastitis control programs. However, a complete and extensive diagnosis, an appropriate therapy, and an efficient mastitis control program will require the combination of clinical examination, microbiological tests, and SCC.  相似文献   

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