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1.
The aim of the research was to assess the prevalence of antibodies to Coxiella burnetii in dairy cattle herds in Poland and to compare the results of real-time PCR and ELISA tests performed on bulk tank milk (BTM) samples. In total, 2635 serum samples collected from 969 dairy cattle herds from all provinces were tested using ELISA. Additionally, BTM specimens from 101 herds were analysed by ELISA and real-time PCR targeting IS1111 element. Presence of anti-C. burnetii antibodies was confirmed in 25.39% of serum samples in 237 herds (24.46%) and the herd-level seroprevalence in Voivodeships varied from 2.5% to 61.4%. Moreover, 46 (45.5%) of analysed bulk tank milk samples gave postive result in ELISA and microbial DNA was detected in 40 (39.6%) of tested herds. The comparative analysis of ELISA and real-time PCR results obtained for BTM samples using the chi-square test showed statistically significant relationship between results of both methods.  相似文献   

2.
Present study is the first attempt to evaluate an indigenous milk ELISA with milk culture, standardize milk PCR, estimate lacto-prevalence of Map and genotype Map DNA from milk samples in few Indian dairy herds. In all 115 cows were sampled from 669 lactating cows in six dairy herds from three districts of North India. Fifty milk samples (four herds) were screened by three tests (milk culture, m-ELISA and m-PCR). Lacto-prevalence of Map in four dairy herds was 84.0% (50.0% in fat and 62.0% in sediment). Screening of both fat and sediment increased the sensitivity of culture. Colonies appeared between 45 and 120 DPI. In indigenous m-ELISA, protoplasmic antigen derived from native Map 'Bison type' strain of goat origin was used. Screening of 115 lactating cows by m-ELISA ('herd screening test') detected 32.1% positive lactating cows (lacto-prevalence). Sensitivity of ELISA was 28.5% and 42.8% in single point cutoff and S/P ratio, respectively. Lacto-prevalence of JD was high in dairy herds (66.6-100.0% by culture and 20.0-50.0% by m-ELISA). DDD farm, Mathura had very high (95.8%) and moderate prevalence of Map and lacto-antibodies, respectively. All cows were clinically suffering from JD. Specific IS 900 PCR was standardized in decontaminated fat and sediment of milk samples. DNA isolated from decontaminated pellets was amplified and characteristic 229 bp band was confirmatory for Map. Of the 50 milk samples, 6.0% were positive in m-PCR. The test needs further standardization. Map DNA were genotyped as Map 'Bison type' by IS 1311 PCR-REA. Of the three tests, milk culture was most sensitive followed by m-ELISA and m-PCR. Map DNA isolated from milk samples of dairy cattle were first time genotyped as Map, 'Bison type' in India. High prevalence of Map in milk of dairy herds, posed major health hazard for calves and human beings.  相似文献   

3.
Cotyledons (n=170) from dairy cattle were analysed for Coxiella burnetii by real-time (rt) PCR targeting the IS1111a and icd genes. Positive cases (n=90) and a random selection of negative cases (n=20) were examined by histology, immunohistochemistry and, if infection level was high, by fluorescence in situ hybridisation. PCR results were compared to bulk tank milk (BTM) antibody levels. Placental infection was detected in cows from herds at all BTM antibody levels. However the likelihood of placental infection was generally higher in herds with intermediate or high BMT antibody levels than in herds with low antibody levels. Histological examination revealed a range of mostly mild cotyledonary changes; C. burnetii infection was only rarely associated with inflammation. This may explain why bovine Q fever is usually not clinically apparent. Nevertheless, infected cattle will shed C. burnetii at calving and this can occur even in herds without BTM antibodies.  相似文献   

4.
Milk samples from 135 herds in Brittany were tested by a blocking ELISA for antibodies to bovine viral diarrhoea virus (BVDV) and used to assess the relationship between the bulk milk result and the within-herd prevalence of antibody-positive lactating cows. This relationship was first quantified by using a general linear model and controlling for the number of cows contributing milk to the bulk tank, for the percentage of primiparous cows in the herds and for the number of milkings contributing to the bulk tank. Receiver operating characteristic (ROC) analysis was then used to define classes of percentage inhibition in the bulk milk associated with minimum intraclass and maximum between-class variances of the within-herd prevalence. Only the percentage inhibition of bulk milk had a significant positive effect on within-herd prevalence (R2 = 0.85). The ROC analysis provided three classes of bulk milk results corresponding to different expected levels of within-herd prevalence. Herds with bulk milk percentage inhibitions of 0 to 35 per cent, 35 to 60 per cent and 60 to 100 per cent had mean (sd) observed prevalences of 4.8 (5.7) per cent, 21.6 (14.6) per cent and 66.0 (29.3) per cent, respectively. Herds with a bulk milk inhibition of 0 to 35 per cent were expected to be BVDV-free. A herd with two consecutive bulk milk results four months apart of 60 per cent or more was likely to have a very high prevalence (median of 93 per cent) and could be suspected of harbouring an active infection.  相似文献   

5.
Despite cattle herds can harbor Coxiella burnetii, risk factors for C. burnetii presence in dairy cattle herds are largely unknown. Therefore, C. burnetii herd prevalence and risk factors for bulk tank milk (BTM) positivity were investigated. In this cross-sectional study, a questionnaire was filled out by the farmer and BTM from 301 farms was tested by ELISA for presence of C. burnetii antibodies and PCR for presence of C. burnetii DNA. Risk factors were identified by univariable and multivariable logistic regression analyses. Antibodies to C. burnetii were detected in 81.6% (CI: 77.2–85.9) and C. burnetii DNA in 18.8% (CI: 14.4–23.1) of the BTM samples. Herd size (OR = 1.1 per 10 cows), cleaning the bedding of the cubicles at most every other day (OR = 2.8) and purchase of cattle from at least two addresses (OR = 3.1) showed a significant and positive association with ELISA positivity and use of an automatic milking system a negative association (OR = 0.3). Risk factors for PCR positivity were purchase of cattle from at least two delivery addresses (OR = 3.2), presence of cows with ticks (OR = 2.0), use of an automatic milking system (OR = 0.2) and presence of goats or sheep on the farm (OR = 0.4). Biosecurity and general hygiene seem associated with introduction and spread of C. burnetii in dairy herds.  相似文献   

6.
This work presents serological evidence of cattle ostertagiosis in the Lower Silesia Region (Poland), based on the measurement of antibodies in bulk tank milk (BTM) samples. It represents the first evidence of this parasite examined with the use of the ELISA test and milk samples in Poland. The prevalence of Ostertagia ostertagii antibodies was determined in BTM from 32 dairy cattle herds. Antibodies to O. ostertagii were demonstrated in all herds. The optical density ratio (ODR) varied from -0.088 to 1.024. The mean ODR value in the examined region was 0.53.  相似文献   

7.
1. EC- and National Regulations. Since 1988 the EC-regulations accept in addition to the on Agar Gel Immunodiffusion test (AGIDT) based blood serum testing of cattle herds that are filed as "free from Enzootic Bovine Leucosis" the use of ELISA for this purpose. The regular testings in dairy cattle herds can be done alternatively with single or pooled milk samples, in other herds with pooled blood sera using ELISA. General condition is only a minimal sensitivity of the test to detect the European EBL Antibody Standard ("E4") in a dilution of 1:10 in negative serum or 1:250 in negative milk. Adequate national regulations are in preparation. The present limitation of pool sizes, blood maximum 50 animals without preparation steps 20, and milk after concentration treatment 50 cows is neutralized by proceedings in development of higher sensitive ELISA tests. This limitation should be canceled. Herd bulk milk samples without size limitations are accepted to be tested with "Milk Ring Test" by EC for the regular testings in filed "Brucellosis Free Dairy Cattle Herds". The alternative use of more sensitive (and more specific) ELISA tests for this purpose including the technical conditions is in a final discussion. 2. Scientific-Technical Base for Using the Chances of the Proceeding in the EC-Regulations. The realisation of the EC accepted or final discussed ELISA based bulk milk testing to control filed "EBL- and/or Brucellosis Free Herds" depends on some basic conditions like sensitivity, specificity, and variability of the ELISA systems. Field trials of more than 20,000 bulk milk samples in case of Brucellosis and more than 2,000 in case of EBL show the feasibilities and the limits of the ELISA systems in defining the status of the herds. The Brucellosis respectively the EBL situations of the dairy cattle herds tested in this trail were well known by history and by investigation of single animal blood samples using conventional tests. Special test run variations of pretested assays demonstrated the possibilities to define the EBL status of dairy cattle herds up to 50 lactating cows without preparation of the bulk milk sample and up 100 after concentration of the antibodies by the rennet-ammonium sulfate method. The concentration limit for detection of Brucellosis antibodies is 100 lactating cows. The bulk milk of smaller herds can be tested without concentration. On principle the evaluation of the test values bases on defined relations to a "weak positive" reference.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

8.
An ELISA developed to diagnose Fasciola hepatica infection in cattle by detecting serum antibodies was adapted and validated for use with samples of bulk-tank milk. The prevalence of the infection in 61 dairy herds was established by using serum antibody levels or faecal egg counts measured in a proportion of the cows in each herd. The correlation between the results of the ELISA and the herd seroprevalence was 0.83. Using a cut-off value of 27 per cent positive, the bulk-tank ELISA identified herds in which more than 25 per cent of the cows were infected with a diagnostic sensitivity of 96 per cent (95 per cent confidence interval 89 to 100 per cent) and a diagnostic specificity of 80 per cent (95 per cent confidence interval 66 to 94 per cent). By applying the ELISA to 623 herds in England and 445 herds in Wales, the prevalence of F hepatica infection in England was estimated to be 48 per cent (95 per cent confidence interval 46 to 54 per cent), and in Wales 86 per cent (95 per cent confidence interval 84 to 90 per cent).  相似文献   

9.
OBJECTIVE: To develop a blocking ELISA for detection of bovine leukemia virus (BLV) antibodies that is comparable to a radioimmunoprecipitation (RIP) assay, to evaluate use of this ELISA for identification of BLV-infected herds, and to develop a polymerase chain reaction (PCR) assay for direct diagnosis of infection with BLV. SAMPLE POPULATION: Serum samples and pooled bulk-tank milk samples from cattle. PROCEDURE: The blocking ELISA was developed, using BLV gp51 as antigen, captured by a selected bovine polyclonal serum. A nested PCR was conducted with primers specific for a segment of the pol region of the BLV genome. RESULTS: Sensitivity and specificity of the ELISA were comparable to those of the RIP assay. Use of the ELISA on pooled milk samples allowed identification of herds in which prevalence of BLV infection among lactating cows was as low as 2.5%. Pooled milk samples from BLV-free herds did not react in the ELISA. All cattle that had positive results for the nested PCR had BLV antibodies, but cattle with consistantly low antibody titers required examination of sequential DNA samples to detect viral sequences. None of the 63 antibody-negative cattle had positive results for the PCR. CONCLUSIONS AND CLINICAL RELEVANCE: This ELISA is a highly specific and sensitive assay for the detection of BLV antibodies in serum and milk samples of cattle. Examination of pooled milk samples with the ELISA provides a reliable, practical, and economic procedure for identification of BLV-infected herds. The nested PCR also constitutes a specific procedure for direct diagnosis of infection with BLV.  相似文献   

10.
The relationship between the level of Neospora caninum antibodies in bulk milk and the seroprevalence in lactating cows was investigated. Bulk milk was also used to estimate the prevalence of N. caninum infection in dairy herds in the northeast and north Thailand. Bulk milk and individual serum from all lactating cows in 11 herds as well as 220 bulk milk samples from nine milk collection centres were analysed for presence of N. caninum antibodies using an iscom ELISA. In the 11 herds the bulk milk absorbances ranged between 0.04 and 0.89 and the seroprevalences varied between 0 and 46%. Five herds had milk absorbances below 0.20, among those were the two herds housing only seronegative lactating cows. In the remaining three herds with such low bulk milk absorbances one or two cows (5-14%) were seropositive. Six of the investigated herds had bulk milk absorbances above 0.20. In the two herds with the highest bulk milk absorbances more than 30% of the cows were seropositive. Using an absorbance of 0.20 to discriminate between negative and positive herds, 102 (46%) of 220 bulk milk samples were judged positive. There was no significant difference in mean bulk milk absorbance between the milk collection centres within each region. However, the proportion of herds with bulk milk absorbances > or =0.50 in the north was statistically (P < 0.01) higher than that in the northeast. It was concluded that bulk milk antibody testing can be used to identify N. caninum-infected herds and that N. caninum is a common infection in dairy herds in Thailand.  相似文献   

11.
Detection of bulk tank milk (BTM) antibodies using ELISA (BTM-ELISA) may constitute an inexpensive test for surveillance of Mycobacterium avium subsp. paratuberculosis (MAP) infection in dairy cattle herds provided that the test is accurate and consistent. The objectives of this study were to determine: (a) the correlation between repeated BTM reactions; and (b) the association between the BTM antibody ELISA-level and the within-herd prevalence of antibody-positive cows.  相似文献   

12.
This study was conducted to determine: (1) the associations between anti-Fasciola hepatica antibody levels in milk and some productive and reproductive parameters in dairy cattle, and (2) the threshold antibody level associated with loss of productivity, at both herd and individual level. Anti-F. hepatica antibodies were analysed by MM3-SERO ELISA in milk samples from the bulk tanks of 490 dairy farms and from 686 lactating cows. The results of general linear model analysis revealed a significant (P<0.05) negative association between the F. hepatica infection status at herd level, determined by analysis of specific antibodies in bulk tank milk, and the average herd milk production. Highly positive herds (MM3-SERO ELISA result>0.405) produced an average of 1.5 kg milk/cow per day less than the negative herds. At cow-level, the mixed model analysis also revealed a significant (P<0.05) association between anti-F. hepatica antibody levels and milk yield. A significant (P<0.05) average reduction of 2 kg milk/day was observed in cows with highly positive ELISA results (>0.762) in relation to cows with negative results. The results of the study led us to conclude that MM3-SERO ELISA is a powerful tool that can be successfully applied, if appropriate "economic thresholds" are established, to identify herds and cows suffering from milk production losses associated with natural infection by F. hepatica.  相似文献   

13.
Thirty-seven bulk tank milk (BTM) and individual milk samples of all contributing cows were tested for Coxiella burnetii detection by a real-time PCR assay and used to assess the relationship between the BTM PCR-response and (i) the within-herd prevalence of milk-shedder cows and (ii) the proportion of heavy milk-shedder cows. The within-herd prevalence of milk-shedder cows (i) was found to be significantly higher in herds with a positive BTM and (ii) increased significantly with the estimated titre in Coxiella burnetii obtained in positive BTM. The proportion of heavy milk-shedder cows among the milk-shedder cows increased significantly with an increased estimated titre in Coxiella burnetii in positive BTM. Therefore, a real-time PCR assay applied to BTM samples collected repeatedly over time appears to be a valuable tool to assess on a larger scale the status of herds towards Coxiella shedding, and to evaluate the efficiency of control actions aimed at controlling and/or preventing Coxiella shedding in dairy herds.  相似文献   

14.
This paper contains observations of several sources of variation in reproductive performance on 13 herds of beef cattle in north-eastern Australia. Nearly 15,000 cows were examined, man, on more than one occasion. Variation between herds in pregnancy rate in June or September 1964, was 44 to 75 per cent. Lactating heifers had lower pregnancy rates than lactating cows, which in turn had lower rates than non-lactating animals. Within classes, cows in poor body condition had lower fertility than those in forward-store or fat condition. Losses of calves between pregnancy tests and branding ranged from 6 to 40 per cent in a sample of herds. In herds where year-to-year data were avail-able, the majority of cattle had one calf every two years, or two calves every three years. In one herd, cows that calved before February reared more calves than those that calved later. The main conclusion was that improved nutrition of lactating heifers and cows would be expected to increase pregnancy rates substantially.  相似文献   

15.
OBJECTIVE: To determine the effect of paratuberculosis on culling, milk production, and milk quality in infected dairy herds. DESIGN: Cross-sectional study. ANIMALS: 689 lactating dairy cows in 9 herds. PROCEDURE: Milk, blood, and fecal samples were obtained from all cows. Fecal samples were evaluated via mycobacterial culture. Serum samples were tested with a commercially available ELISA for antibodies against Mycobacterium avium subsp paratuberculosis, and preserved milk samples were tested with an ELISA for antibodies against M paratuberculosis. Mixed effect and proportional hazards models were used to determine the effect of paratuberculosis on 305-day milk, fat, and protein production; somatic cell count linear score; and the risk of culling. RESULTS: Cows with positive results of bacteriologic culture of feces and milk ELISA produced less milk, fat, and protein, compared with herdmates with negative results. No difference in 305-day milk or fat production was detected in cows with positive results of serum ELISA, compared with seronegative cows. The 3 survival analyses revealed that cows with positive results of each test were at higher risk of being culled than cows with negative results. Paratuberculosis status, as determined by use of all 3 diagnostic tests, was not associated with milk somatic cell count linear score. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that for the 9 herds in this study, paratuberculosis significantly decreased milk production and cow longevity.  相似文献   

16.
A commercial ELISA detecting antibodies against bovine viral diarrhoea Virus (BVDV) was analysed for its applicability for bulk-milk screening. Detection limits were analysed using native and concentrated milk samples (milk treated with rennet and ammonium sulfate precipitated) from 10 cows whose sera showed different reactivity levels in the ELISA and from two cows which gave birth to persistently infected calves during the last year. Further this and a second commercial ELISA were used to screen 591 randomly selected bulk-milk samples. To clarify discrepancies thirty-nine herds were included in a follow-up study. A second bulk-milk sample and serum samples from 10 young cattle of 6 to 28 month of age per herd were analysed for antibodies against BVDV. The results of this second testing and the detection of viremic animals in 4 herds confirmed the results from initial bulk-milk testing with both tests. The analysed test is suitable for bulk-milk testing although its application is limited by vaccination.  相似文献   

17.
AIMS: To assess the sensitivity and specificity of a bulk tank milk (BTM) antibody enzyme-linked immunosorbent assay (ELISA) to detect likely infection of a dairy herd with bovine viral diarrhoea virus (BVDV). The ELISA was subsequently used to estimate the prevalence of likely infected herds in parts of the North Island of New Zealand. METHODS: BTM samples from 724 randomly selected dairy herds in the Waikato, Bay of Plenty and Northland regions of New Zealand were tested for BVDV antibodies. From this group, 20 herds were again randomly selected from each of the quartiles of the ELISA percentage inhibition (%INH) result. From each participant herd, serum from 15 randomly selected calves aged 6-18 months and 15 cows was collected and tested using an indirect blocking ELISA for BVDV antibodies. RESULTS: Among serum results from calves from 50 herds available for analysis, 34 (68%) herds were classified as likely non-infected (0-3 seropositive among 15 calves) and 16 (32%) as likely infected (5-15 seropositive among 15 calves). Receiver-operator characteristic (ROC) analysis identified an optimal cut-off for BTM of 80%INH associated with 81% sensitivity and 91% specificity for likely herd infection. The prevalence of BVDV antibodies in cows within herds and %INH for BVDV in bulk milk were positively correlated (p<0.01). The association between bulk milk %INH and the prevalence of BVDV antibodies in calves was stronger than the same association in cows. Based on the threshold of 80%INH, the 95% confidence interval (CI) for prevalence of likely infection in the 724 herds in the Waikato, Bay of Plenty and Northland regions of New Zealand was 12-17%. Vaccination against BVDV was not significantly associated with the likely infection status of the herd based on prevalence of BVDV antibodies among calves. CONCLUSION: An ELISA test result for BVDV antibodies in BTM >/=80%INH can be used as a threshold to indicate the presence of likely infection with BVDV in dairy herds in New Zealand, with 81% sensitivity and 91% specificity.  相似文献   

18.
At the end of August and the first two weeks of September 2011 dozens of veterinary practitioners reported to GD Veekijker (Animal Health Service) several dairy herds with cows with sudden decreased milk production, watery diarrhea and sometimes fever. In the beginning these reports came from the Eastern region of the Netherlands, after that also from the other three regions. The percentages of diseased herds per veterinary practice varied from a few till dozens per cent. Extensive bacteriological, virological and parasitological testing of the feces of sick cows did not reveal an infectious cause of the clinical problems. Recently, 50 stored blood samples of clinically diseased cattle were tested for the Schmallenbergvirus using a PCR, and 36% (18/50) tested positive. A large group of control cows (n=115) was also tested with the PCR and all cattle tested negative. Likely the Schmallenbergvirus was the primary cause of the clinical symptoms in the Dutch dairy herds. Further research will be done to confirm this.  相似文献   

19.
An enzyme-linked immunosorbent assay (ELISA) using bulk tank milk samples was evaluated as a screening test for bovine tuberculosis (TB), a contagious chronic disease of cattle. An ELISA with MPB70, a major antigen of Mycobacterium bovis was performed using paired sets of milk and sera samples from 33 tuberculin-positive and 43 tuberculin-negative cattle. Anti-MPB70 antibodies were detected in milk samples and there was a significant correlation between seroreactivities of milk and sera samples (R2 = 0.83). Using the tuberculin skin test as the reference test, the sensitivities of ELISA using milk and sera samples were 87.8% and 81.8%, respectively, and the specificities were 97.7% and 100%, respectively.In the screening test using bulk tank milk samples from 931 dairy herds in Whasung, Gyeonggi-do, Korea, the positive rate for anti-MPB70 antibody was 4.5% (42/931) and the tuberculin-positive rate was 2.8% (26/931). Individual milk samples (n = 253) were collected from randomly selected 8 problematic and 3 negative herds (positive and negative in the screening test by MPB70 ELISA using bulk tank milk samples, respectively) and tested by MPB70 milk ELISA. In the problematic herds, positive rates were 10.5% (20/190) for anti-MPB70 antibodies in milk ELISA and 2.1% (4/190) in the tuberculin skin test. More than one dairy cows were positive by milk ELISA among the problematic herds, and all tuberculin-positive dairy cows were positive in the milk ELISA. Further, no positive cows were detected in negative herds both by milk ELISA and tuberculin skin test. These results suggest that an ELISA, using bulk tank milk samples, might be a potential efficient screening test for bovine TB of dairy cows.  相似文献   

20.
Levels of antibodies to the O antigens (O:1,9,12) of Salmonella dublin were tested in 1355 serum, 1143 cow milk and 160 bulk milk samples from dairy herds using an enzyme-linked immunosorbent assay (ELISA). In order to define the background reaction, milk samples from all lactating cows and serum samples from 9 animals were collected in each of 20 salmonellosis-free herds located on the island of Bornholm, where cattle salmonellosis has not been reported. Similar samples were collected from all stalled animals in 10 herds with recent (< 6 months) outbreaks of salmonellosis located in Jutland, where salmonella infection is enzootic. Using herd history of salmonellosis, herd location and clinical status of the herds as criteria, the optimal cutoff in the milk ELISA was determined as being at least 5% of the samples having optical density > 0.5, resulting in herd sensitivity of 1.0 and herd specificity of 0.95. While none of the sera in the herds from Bornholm was ELISA positive, 2 herds had a few reactors in the milk ELISA. Using the same cutoff, all but 1 bulk milk sample from 150 herds on Bornholm was ELISA-negative, and all 10 salmonellosis-positive herds from Jutland were ELISA-positive. A significant correlation was found between ELISA reactions in milk and in serum of cows (34% and 32% respectively, rs = 0.69, P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

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