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1.
CASE HISTORY: An increase in the bulk somatic cell count (BSCC) of up to 1,000 × 103 cells/ml occurred in a dairy herd in Israel at the end of 2001 and beginning of 2002.

CLINICAL FINDINGS: Bacteriological examination of milk from 69 cows revealed a high prevalence of Streptococcus group G bacteria, identified as S. canis, affecting 38% of cows and 20% of all quarters. Isolates were sensitive to cephalothin and moderately sensitive to penicillin G. Infected cows were separated from the herd, treated with intramammary antibiotics, milked last, and strict hygiene practices were introduced to the milking routine. The pathogen was cleared from the herd and BSCC decreased to 250-350 × 103 cells/ml after 6 months.

DIAGNOSIS: Streptococcus canis mastitis.

CLINICAL RELEVANCE: Streptococcus canis infection may cause subclinical mastitis and high bulk SCC in dairy herds and be resolved by treatment with intramammary antibiotics and the introduction of strict hygiene practices.  相似文献   

2.
In 57 Holstein cows where the dairy farm uses a milking parlor system, the somatic cell count (SCC) increased persistently in the bulk milk (monthly mean 52.3 x 10(4) cells/ml; range 21 to 94 x 10(4) cells/ml). We detected S. aureus in 24 (41.2%) of the 54 lactating cows and in 29 (12.8%) of 227 quarters of the 57 milking cows in the herd. A control program was implemented in an effort to eradicate S. aureus mastitis from this dairy farm. The control plan established improved handling of the lactating cows, improved milking procedures, dry-cow therapy, and culling of infected cows. The program was monitored for 3.5 years by frequent checkups on the rate of S. aureus infection, the SCC, and the changes in milk composition. Eighteen months after the control program was started, the rate of S. aureus infection in the quarter milk decreased dramatically, and no S. aureus isolates were found in the milk of the remaining cows. The SCC in the bulk milk of the herd dropped to a monthly mean of <20 x 10(4) cells/ml. In conclusion, the control program was effective for controlling persistent S. aureus mastitis in this dairy herd.  相似文献   

3.
Thirty-two dairy herds, 16 with low somatic cell counts (LSCC; Dairy Herd Improvement Association 12-month mean herd SCC less than or equal to 150,000 cells/ml) and 16 with high somatic cell counts (HSCC; Dairy Herd Improvement Association 12-month mean herd SCC greater than or equal to 700,000 cells/ml) were evaluated to determine the relationship between the prevalence of mastitis in each herd and each herd's mastitis control and management practices. Once for each herd, duplicate quarter milk samples were collected from the lactating cows, a survey of herd mastitis control, milking hygiene, and management practices of each herd was performed, and milking-machine function was evaluated. Of the 16 herds with LSCC, 2 (12.5%) had Streptococcus agalactiae isolated and 7 (44%) had Staphylococcus aureus isolated. Both organisms were found in all of the herds with HSCC. In herds with LSCC, the mean percentage of quarters infected with Str agalactiae was 0.1%, the mean percentage infected with streptococci other than Str agalactiae was 1.9%, and the mean infected with S aureus was 0.7%. In herds with HSCC, 25.7% of the quarters were infected with Str agalactiae, 3.7% were infected with streptococci other than Str agalactiae, and 7.6% were infected with S aureus. A program of postmilking teat dipping and treatment of all cows at the beginning of the nonlactating period was practiced more frequently in the herds with LSCC (81.3%) than in the herds with HSCC (37.5%). Major differences were not found between the 2 groups of herds in the use of the more common milking hygiene techniques or in the maintenance and functional characteristics of the milking equipment.  相似文献   

4.
Samples of bulk tank milk and cow-composite milk from 23,138 dairy cows from 50 California dairies were examined by use of microbiologic procedures. The number of colonies of mastitis pathogens isolated per milliliter of bulk tank milk (used as a predictor of the percentage of infected cows in the herd) was evaluated, using simple regression analysis and Spearman's rank correlation. Correlations between the pathogens and the percentage of cows in each herd shedding the pathogens were found for Streptococcus agalactiae (r = 0.71) and mycoplasma (r = 0.59), but were considerably lower for other pathogens. When greater than or equal to 4,000 colonies of Streptococcus agalactiae were found per milliliter of bulk tank milk, at least 7% of the cows in the herd was shedding this organism. However, a pattern was not found between the number of mycoplasma colonies per milliliter of bulk tank milk and the percentage of infected cows in the herd.  相似文献   

5.
Streptococcus agalactiae mastitis: a review.   总被引：4，自引：0，他引：4       下载免费PDF全文
Streptococcus agalactiae continues to be a major cause of subclinical mastitis in dairy cattle and a source of economic loss for the industry. Veterinarians are often asked to provide information on herd level control and eradication of S. agalactiae mastitis. This review collects and collates relevant publications on the subject. The literature search was conducted in 1993 on the Agricola database. Articles related to S. agalactiae epidemiology, pathogen identification techniques, milk quality consequences, and control, prevention, and therapy were included. Streptococcus agalactiae is an oblique parasite of the bovine mammary gland and is susceptible to treatment with a variety of antibiotics. Despite this fact, where state or provincial census data are available, herd prevalence levels range from 11% (Alberta, 1991) to 47% (Vermont, 1985). Infection with S. agalactiae is associated with elevated somatic cell count and total bacteria count and a decrease in the quantity and quality of milk products produced. Bulk tank milk culture has, using traditional milk culture techniques, had a low sensitivity for identifying S. agalactiae at the herd level. New culture methods, using selective media and large inocula, have substantially improved the sensitivity of bulk tank culture. Efficacy of therapy on individual cows remains high. Protocols for therapy of all infected animals in a herd are generally successful in eradicating the pathogen from the herd, especially if they are followed up with good udder hygiene techniques.  相似文献   

6.
AIM: To determine the prevalence of clinical mastitis in spring-calving dairy herds in the Waikato Region of New Zealand and to identify factors associated with variation in the prevalence of clinical mastitis between herds. METHOD: A total of 799 quarters from 595 dairy cows from 38 dairy herds were diagnosed by herd owners as having clinical mastitis between 8 July and 21 August 1997. Quarters diagnosed with clinical mastitis were sampled for bacterial culture and somatic cell count, and the presence of clots in the milk and the presence of udder oedema were assessed by a technician or veterinarian. RESULTS: Clinical mastitis was diagnosed in an average (+/-s.e.m.) of 9.9% (+/-0.8%, range 0.9-21.4%) of calved cows within the herds. Bacteria were not cultured from an average of 12.4 % (+/- 2.0%, range 0.0-45.5%) of cows and 22.3% (+/- 2.4%, range 0.0-54.0%) of quarters diagnosed as having clinical mastitis. There were significant differences between herds in the proportion of cows diagnosed with mastitis and in the proportion of clinical mastitis cases from which bacteria were not cultured. A decreased prevalence of clinical mastitis (p<0.001) was associated with an increased percentage of the herd treated with dry cow antibiotics. An increased prevalence of clinical mastitis (p<0.0001) was associated with both an increased percentage of cows treated in the previous season with lactating cow antibiotics and an increased percentage of heifers in the herd. Herds that were fed supplements before or during lactation had a higher prevalence of clinical mastitis than herds that were not fed supplements (p<0.001). An increased proportion of quarters diagnosed with clinical mastitis that did not culture bacteria was associated with an increased prevalence of clinical mastitis (p<0.001). The proportion of quarters that the technician or veterinarian found with evidence of clinical mastitis (i.e. a somatic cell count >500,000 cells/ml and the presence of either clots or udder oedema) within a herd was inversely related to the proportion of quarters within a herd from which no bacteria were isolated. CONCLUSION: There was a large variation in the prevalence of clinical mastitis and in the proportion of clinical quarters from which no bacteria were grown between herds. Management factors such as the use of dry cow therapy, feeding regimes and heifer replacement rates all affected the prevalence of clinical mastitis. Herd owners appear to differ in the sensitivity and specificity of their diagnosis of clinical mastitis, with bacteria not isolated from up to 50% of quarters diagnosed with clinical mastitis in some herds. Improvements in the specificity of herd owner diagnosis of clinical mastitis may reduce the use of antibiotics for mastitis during lactation and hence may reduce the risk of antibiotic contamination of milk supplied for human consumption.  相似文献   

7.
This study is reporting an outbreak of subclinical mastitis due to beta-hemolytic group L streptococci in an Austrian dairy herd with a history of high somatic cell count. At the first survey 16 of 33 lactating cows (28 quarters of 132) were cultured positive for beta-hemolytic, CAMP and esculin negative cocci that grew on Columbia blood agar with small grey catalase negative colonies. With the commercial API 20 Strep system (bioMerieux, F) isolates were classified as members of streptococci group L. All tested strains (eight of 28) produced acid from ribose, lactose, trehalose, amidon and glycogen; they hydrolysed hippurate and showed beta-glucuronidase, beta-galactosidase, alkaline phosphatase, leucinaminopeptidase and arginindehydrolase activity. Isolates were sensitive to bacitracin but resistant to tetracycline. Using phenotypic characterisation as well as sequence analysis of the 16S-23S intergenic spacer region of a representative strain, recovered isolates were identified as Streptococcus (S.) dysgalactiae ssp. equisimilis. Mastitis was characterized by normal milk secretions and absence of clinical abnormalities but high elevations of somatic cell count. Based on the characteristics of the strains and on the observations during the first herd survey, contagious transmission during milking as a result of poor milking hygiene was assumed. The mastitis was controlled through implementation of a strict hygiene protocol including use of single-use udder towels, post milking teat desinfection and cluster disinfection between milking cows in combination with antibiotic treatment of infected udders.  相似文献   

8.
CASE DESCRIPTION: 9 first-lactation dairy cows in a closed dairy herd had swelling in the forelimbs and forelimb lameness. Mycoplasmal arthritis and mastitis were diagnosed. CLINICAL FINDINGS: Swelling of the carpal joint, diffuse subcutaneous edema from the carpal to metacarpophalangeal joints, and forelimb lameness were evident in 9 first-lactation cows 7 to 21 days after parturition. Diagnostic testing revealed that 3 of 3 bulk-tank milk samples, 3 milk samples from cows with clinical mastitis, 2 fluid samples obtained from arthritic joints, and samples from the lungs and spleen of a cow that had died yielded positive results for Mycoplasma spp. Nucleic acid sequence analysis performed by use of a PCR assay on the joint fluid and lung tissues confirmed infection with Mycoplasma bovis. TREATMENT AND OUTCOME: Affected cows were treated by IM administration of flunixin meglumine and dexamethasone for 3 days. All cows were nonresponsive to treatment (3 cows died, and the other 6 were culled). Follow-up culture for Mycoplasma spp of milk samples from the bulk tank and from all lactating cows was recommended to screen for chronic subclinical carriers. CLINICAL RELEVANCE: Mycoplasmal infections may cause unusual initial clinical signs or an atypical history. When dairy cattle, including those residing in closed herds, have lameness, swelling of the carpal or metacarpophalangeal joints, edema of the distal portions of the forelimbs, or polyarthritis, infection with Mycoplasma spp should be investigated. Delay in diagnosis of mycoplasmal infections in dairy herds can result in substantial financial loss and the establishment of chronic subclinical carriers.  相似文献   

9.
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 x 103 at 1 month prior to the outbreak to a peak of 1200 x 10(3) 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   

10.
A commercially available, penicillin-novobiocin, intramammary infusion product and a solution of procaine penicillin G (1.2 X 10(6) IU) in 10 ml of sterile saline solution were evaluated for their comparative efficacies against Streptococcus agalactiae mastitis in 3 California dairy herds. After composite milk samples from each cow in each herd were bacteriologically cultured, cows infected with S agalactiae (n = 228) were assigned randomly to 2 treatment groups. Milk samples were reevaluated bacteriologically 21 to 25 days after treatment. Both preparations were highly effective against S agalactiae in first-lactation cows and in cows scored negative or trace by use of the California Mastitis Test. Efficacy was significantly decreased in cows with California Mastitis Test scores of 1, 2, or 3. Herd and treatment were associated significantly with treatment success or failure. Most treatment failures were in one herd in cows that were given procaine penicillin G in sterile saline solution. Milk production and lactation stage were not associated with success or failure of treatment.  相似文献   

11.
Research has shown that total bacterial count (TBC), which is the bacterial growth per ml of milk over a fixed period of time, can be decreased by good hygiene and farm management practices. The objective of the current study was to quantify the associations between herd management factors and bulk tank TBC in Irish spring calving, grass-based dairy herds. The relationship between bulk tank TBC and farm management and infrastructure was examined using data from 400 randomly selected Irish dairy farms where the basal diet was grazed grass. Herd management factors associated with bulk tank TBC were identified using linear models with herd annual total bacterial score (i.e., arithmetic mean of the natural logarithm of bulk tank TBC) included as the dependent variable. All herd management factors were individually analysed in a separate regression model, that included an adjustment for geographical location of the farm. A multiple stepwise regression model was subsequently developed. Median bulk tank TBC for the sample herds was 18,483 cells/ml ranging from 10,441 to 130,458 cells/ml. Results from the multivariate analysis indicated that the following management practices were associated with low TBC; use of heated water in the milking parlour; participation in a milk recording scheme; and tail clipping of cows at a frequency greater than once per year. Increased level of hygiene of the parlour and cubicles were also associated with lower TBC. Herd management factors associated with bulk tank TBC in Irish grazing herds were generally in agreement with most previous studies from confinement systems of milk production.  相似文献   

12.
OBJECTIVE: To determine herd characteristics and management practices associated with milk production in dairy herds enrolled in official Dairy Herd Improvement Association (DHIA) programs in Ohio. SAMPLE POPULATION: 186 dairy farms in Ohio. PROCEDURE: All herds in official DHIA programs in 9 counties were invited to participate. Information regarding herd characteristics and management practices was obtained, using a standardized questionnaire. Bulk-tank milk samples were obtained for bacteriologic culture. Official DHIA test-day records were obtained, and associations were identified, using multivariable ANOVA procedures. RESULTS: Of 479 eligible producers, 186 (39%) participated, and consecutive bulk-tank milk samples were available for culture from 172 (36%). Streptococcus agalactiae and Mycoplasma spp were not recovered from bulk-tank milk samples, but Staphylococcus aureus was recovered from 64 (37%) herds. Mean (+/- SD) number of lactating cows in participating herds was 97+/-66, with 123 (66%) herds milking < 100 cows. The RHA was significantly associated with number of cows in milk, estimated percentage of herd detected in estrus, reported annual percentage of heifer calves born alive that died before 8 weeks old, percentage days in milk, use of bovine somatotropin during the preceding 2 years, and sex of the person completing the questionnaire. CONCLUSIONS AND CLINICAL RELEVANCE: In this study, the strongest indicator of milk production was number of cows in milk. However, merely adding cows to a herd should not be considered to guarantee increased milk production, because other management traits could be confounded with increased number of cows in a herd.  相似文献   

13.
AIM: To evaluate the benefit of blanket treatment of all milking cows at drying-off and all replacement heifers one month prior to the planned start of mating with an internal teat sealant on the incidence of mastitis, and somatic cell counts (SCC), postpartum in a 650-cow herd with a mastitis incidence in early lactation of 15% in cows and 26% in heifers. METHODS: Prior to drying-off, lactating cattle were divided on the basis of SCC and mastitis history. Cattle with records of individual SCC >150,000 cells/ml or mastitis in the previous lactation were treated with a cloxacillin-based dry-cow therapy (DCT), while the remaining cattle received no antibiotics. Cattle in each of the two groups were then randomly assigned to receive either an internal teat sealant or no further treatment. Additionally, one month prior to the planned start of calving the rising 2-year-old heifers were also randomly assigned to receive either an internal teat sealant or no treatment. All clinical mastitis cases were recorded for the first 10 weeks after the start of calving, while SCC were measured on three occasions during the subsequent lactation. RESULTS: Data were available from 466 cows and 206 heifers; treatment with the internal teat sealant significantly reduced the incidence of mastitis in both groups. For cows, the reduced risk of mastitis due to treatment with the teat sealant was not significantly different between cows, which, based on their mastitis history, required dry-cow antibiotics and those which did not. There was no effect of teat sealant on the mean SCC of any group at any time-point. CONCLUSIONS: On this farm, treatment of all cows and heifers prior to parturition with an internal teat sealant significantly reduced the risk of clinical mastitis. The benefits of an internal teat sealant were the same when used in combination with antibiotics in cows with a history of mastitis as when used alone in cows with no such history. CLINICAL RELEVANCE: These data support the proposition that blanket treatment with an internal teat sealant of all cows due to enter the milking herd can be a useful method of mastitis control. They also suggest that combined therapy with dry-cow antibiotics and internal teat sealants can be beneficial under New Zealand conditions. More detailed research on more farms in more areas of New Zealand is required to confirm these suggestions.  相似文献   

14.
OBJECTIVE: To evaluate associations among herd infection status, herd management practices, and familiarity of the herd manager with Mycobacterium paratuberculosis (Johne's disease) or prior disease diagnosis in that herd to support development of Johne's disease-control programs. DESIGN: Population-based cross-sectional study. SAMPLE POPULATION: 1,004 US dairies, each with > or = 30 cows, representing 79.4% of US dairy cows. PROCEDURE: Questionnaires were administered to dairy managers, and blood samples were collected from cows during herd visits. Sera were tested for antibodies to M paratuberculosis, using a commercially available ELISA. Multivariable logistic regression analyses were used to evaluate associations between use of management practices, herd disease status, and familiarity of the manager with Johne's disease or prior diagnosis of Johne's disease in that herd. RESULTS: Results from serologic testing revealed that 3.4% of cows and 21.6% of dairy herds were infected with M paratuberculosis. Factors associated with infection included number of cows in herd, region of country, percentage of cows born at other dairies, group housing for periparturient cows, and group housing for preweaned calves. Few preventive practices were positively associated with prior diagnosis of Johne's disease (time of separation of newborn calf from dam) or familiarity of the manager with the disease (teats and udder washed before colostrum collected). CONCLUSIONS AND CLINICAL RELEVANCE: Risk factors associated with Johne's disease in this study confirmed those management practices generally recommended for disease control. An educational problem, however, is the finding that herd managers familiar with Johne's disease generally use management practices similar to those used by managers unfamiliar with the disease.  相似文献   

15.
主要介绍了乳房炎患病牛乳中病原微生物污染情况、耐药情况及防控措施。总结出乳房炎患病牛乳中的病原微生物种类较多, 主要有大肠杆菌、金黄色葡萄球菌、链球菌和克雷伯菌, 不同地区乳房炎乳样中的病原微生物不同, 产生的耐药性和耐药基因存在差异。旨在为减少因滥用和乱用抗生素导致药物残留和耐药性产生、降低乳房炎患病牛乳中病原微生物的污染以及科学、合理用药提供参考。  相似文献   

16.
AIM: To evaluate the accuracy of a hand-held electrical conductivity meter for the detection of subclinical mastitis in an Australian dairy herd in late lactation. METHODS: A hand-held conductivity meter was evaluated during late lactation in a herd of dairy cows that had a high prevalence of Streptococcus agalactiae and Staphylococcus aureus infection. The ability of the conductivity meter to accurately discriminate between uninfected quarters and those infected with major pathogens was assessed, using bacteriology as the definitive test for infection status. Milk samples for bacteriology, and electrical conductivity measurements, were collected from 233 quarters from 59 cows. The ability of the device to identify infected and uninfected cows was also assessed. Sensitivity and specificity were calculated for a range of threshold values, using absolute values, the range of quarter values within a cow and the ratio of quarter values within a cow. RESULTS: Electrical conductivity was higher in infected quarters than uninfected quarters, but the degree of overlap between the populations was substantial, even when quarters were assessed as case-control pairs from the same cow. Use of the device according to the manufacturer's recommendations for diagnostic criteria of mastitic quarters had a sensitivity of 51% and a specificity of 71%. The ability of the device to correctly diagnose the infection status of cows was dependent on both the analytical method and the threshold value used. Applying the manufacturer's recommended criteria to the diagnosis of the status of cows, the sensitivity of the test was 91% and the specificity 17%. CONCLUSION: The variability between individual quarters and between cows in this study was such that the use of this device to measure the conductivity of milk was not a reliable method by which to diagnose subclinical mastitis in cows in late lactation. CLINICAL RELEVANCE: Interpretation of results from handheld conductivity meters when used for the diagnosis of subclinical mastitis in dairy cows needs to be made with care. In some circumstances the results obtained do not accurately reflect the bacteriological status of either individual quarters, or cows.  相似文献   

17.
A cross-sectional survey of 523 dairy farms in the south of Chile was carried out to quantify risk factors associated with bulk-milk somatic-cell count (BMSCC) >200 x 10(3)cells/ml.Questionnaires followed by one reminder were sent to 3710 dairy farms via the 11 milk-processing plants that they supplied in October 1998. The response proportion was 14.1%. The median BMSCC was 289 x 10(3) cells/ml (range: 74 x 10(3) to 1800 x 10(3)cells/ml). The median herd size was 70 cows (range: 7-616); herd size was not associated with BMSCC. The annual milk yield of 33.2% of the herds was <4000 l and 53.4% had an annual milk yield of 4 x 10(3) to 6 x 10(3) l. Clinical-mastitis records were kept by 55.3% of the farmers. Seventy-six percent of the farmers (377/499) reported <10 clinical cases of mastitis in the year prior to the questionnaire.Logistic multiple regression indicated that BMSCC >200 x 10(3)cells/ml was more likely when foremilking was practised, and when cows were collected in a yard before milking. BMSCC was less likely to be >200 x 10(3)cells/ml when teats were washed with water containing disinfectant compared with plain water; when the udder and teats were always checked before milking compared with, sometimes or never; when cows with mastitis were milked first compared with any other ordering, and when farmers recorded individual-cow somatic-cell count (ICSCC) compared with when ICSCC was not recorded.  相似文献   

18.
Dairy production is not traditional in Vietnam. The farmers have little practical knowledge and udder health control is generally lacking. In order to give the farmers appropriate advice, knowledge about the distribution of udder pathogens is crucial. The aim of the study was to investigate the prevalence of sub-clinical mastitis and to identify udder pathogens isolated from smallholder dairy herds in Southern Vietnam. Twenty farms with a herd somatic cell count (SCC) ranging from low (≤400?×?103?cells/mL) to high (>400?×?103?cells/mL) were randomly selected. Milk samples were collected from 458 quarters of 115 clinically healthy cows. SCC was analyzed on farm by a portable cell counter. Bacteriological samples were taken using Mastistrip© cassettes and sent to Sweden for examination. For all herds the mean herd SCC was 632?×?103/mL milk. The prevalence of subclinical mastitis at quarter SCC basis was 63.2 % and at cow basis 88.6 %. Only 40 % of all cows were bacteriologically negative in all quarters. Streptococcus agalactiae was the most commonly found bacteria species, isolated from 96 of the 458 quarter samples, in 13 of the 20 farms. The results indicate pronounced subclinical mastitis problems among the dairy cows in this region mainly due to infections with S. agalactiae. The high prevalence of this highly contagious pathogen is probably attributable to the generally poor milking hygiene and low awareness of proper measures to prevent occurrence and spread of udder infections. A strict, targeted action program for the herds in this area is required in order to lower the prevalence of subclinical mastitis.  相似文献   

19.
OBJECTIVE: To identify herd characteristics and management practices associated with bulk-tank somatic cell counts (BTSCC) in dairy herds in Ohio enrolled in official Dairy Herd Improvement Association (DHIA) programs. SAMPLE POPULATION: 186 dairies in Ohio. PROCEDURE: All herds in official DHIA programs in 9 counties were asked to participate. Extensive information regarding herd characteristics and management practices was obtained, using a standardized questionnaire. Bulk-tank milk samples were requested from all participating herds for bacterial culture. Official DHIA test-day records for January 1997 were obtained from all herds enrolled in official DHIA programs in the 9 counties. Potential associations were identified, using multivariable ANOVA. RESULTS: Participation was 186 of 479 (39%) herds. Streptococcus agalactiae and Mycoplasma spp were not isolated from bulk-tank milk samples. Staphylococcus aureus was isolated from 64 of 172 (37%) of the herds. The BTSCC were inversely associated with peak daily milk production, postmilking teat disinfection, percentage of eligible cows in the herd detected in estrus, and directly related to the extent to which BTSCC was perceived as a herd problem during the preceding 2 years. Type of housing for nonlactating cows and product used for treatment of nonlactating cows also were significantly associated with BTSCC. CONCLUSIONS AND CLINICAL RELEVANCE: Consideration of herd characteristics and implementation of management practices associated with BTSCC could result in increased milk yield and production of milk with lower BTSCC.  相似文献   

20.
During two years in a herd of dairy cows with an average number of 94 cows the effects on infection level were investigated of single nonselective antibiotics treatment of cow's udder in the dry period. The treatment influenced favourably the results of complex periodic three-months examinations: --level of infection with infectious mastitis was reduced from 38.3% to 9.8%; --occurrence of clinical forms of mastitis dropped from 17.4% to 5.9%;--occurrence of NK-test positive reactions decreased from 55.8% to 21.8%. An investigation into therapeutic efficiency of three intramammary preparations revealed the highest total therapeutic effect of Stapenor retard (Bayer, FRG)--93.2%; Syntarpene 500 (Polfa, Poland) had the total therapeutic efficiency of 92.6% and the efficiency of Oxaclene foam (Spofa, CSSR) made 86.5%. The results demonstrate good efficiency of the method because the levels of mastitis infection in the herd were positively influenced, and excellent therapeutic efficiency of semisynthetic penicillins containing intramammary preparations used for mastitis treatment of dairy cows in the dry period.  相似文献   

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