Bulk Milk Samples Research Articles

A large factory-scale application of selected autochthonous lactic acid bacteria for PDO Pecorino Siciliano cheese production

The main hypothesis of this study was that the autochthonous lactic acid bacteria (LAB) selected for their dairy traits are able to stabilize the production of PDO (Protected Denomination of Origin) Pecorino Siciliano cheese, preserving its typicality. The experimental plan included the application of a multi-strain lactic acid bacteria (LAB) culture, composed of starter (Lactococcus lactis subsp. lactis CAG4 and CAG37) and non starter (Enterococcus faecalis PSL71, Lactococcus garviae PSL67 and Streptococcus macedonicus PSL72) strains, during the traditional production of cheese at large scale level in six factories located in different areas of Sicily. The cheese making processes were followed from milk to ripened cheeses and the effects of the added LAB were evaluated on the microbiological, chemico-physical and sensorial characteristics of the final products. Results highlighted a high variability for all investigated parameters and the dominance of LAB cocci in bulk milk samples. The experimental curds showed a faster pH drop than control curds and the levels of LAB estimated in 5-month ripened experimental cheeses (7.59 and 7.27 Log CFU/g for rods and cocci, respectively) were higher than those of control cheeses (7.02 and 6.61 Log CFU/g for rods and cocci, respectively). The comparison of the bacterial isolates by randomly amplified polymorphic DNA (RAPD)-PCR evidenced the dominance of the added starter lactococci over native milk and vat LAB, while the added non starter LAB were found at almost the same levels of the indigenous strains. The sensory evaluation showed that the mixed LAB culture did not influence the majority of the sensory attributes of the cheeses and that each factory produced cheeses with unique characteristics. Finally, the multivariate statistical analysis based on all parameters evaluated on the ripened cheeses showed the dissimilarities and the relationships among cheeses. Thus, the main hypothesis of the work was accepted since the quality parameters of the final cheeses were stabilized, but all cheeses maintained their local typicality.

Monitoring the Freezing Point of Buffalo Milk.

The aim of this study was to evaluate the basic freezing point of buffalo milk. Bulk milk samples were collected from buffalo and cattle farms in Caserta area from 2008 to 2014. The analysis involved a total of 1886 buffalo milk samples and 1711 bovine milk samples. These were also tested for fat, protein and lactose contents by means of infrared spectrometry. The freezing point was determined by means of a thermistor cryoscope. Data underwent statistical analysis. Our research showed an average freezing point of -0.528°C for buffalo milk and -0.522°C for bovine milk. Given the lack of data on the freezing point of buffalo milk, our study provides the first indication of a basic freezing point of the milk of this species in Italy.

Staphylococcus aureus Isolates from Goat and Sheep Milk Seem to Be Closely Related and Differ from Isolates Detected from Bovine Milk.

Dairy goat and sheep farms suffer severe economic losses due to intramammary infections, with Staphylococcus aureus representing the main cause of clinical mastitis in small ruminants. In addition, S. aureus contamination of goat and sheep milk may cause staphylococcal food poisoning, as many traditional caprine and ovine milk products are not subjected to pasteurization. Data on virulence and antimicrobial resistance genes, as well as on the clonality of S. aureus detected in goat and sheep milk is scarce. Therefore, it was the aim of this study to determine (i) spa types and clonal complexes (CC) and (ii) virulence and resistance gene profiles of S. aureus isolated from goat and sheep milk. A total of 162 milk samples from sheep and goats presenting signs of an intramammary infection and 104 bulk milk samples were collected. While low prevalence rates of S. aureus was detected on single animal level, 46% of the bulk tank milk samples from small ruminants were positive for S. aureus. All isolates were spa typed and CC and virulence and resistance gene patterns were determined using a DNA microarray. Data from 49 S. aureus isolates was included in the statistical analysis and the construction of a SplitsTree. The analyzed isolates could be assigned to eleven CC, with the large majority of goat and sheep isolates being assigned to CC130 and CC133. The findings of this study suggest that S. aureus shows pronounced adaptation to small ruminants in general, but not to sheep or goats in particular. Although some common characteristics among S. aureus from caprine, ovine, and bovine milk samples were observed, S. aureus from small ruminants seem to form a distinct population. As 67% of the detected S. aureus strains exhibited at least one enterotoxin gene, many caprine, or ovine raw milk products may be contaminated with low levels of enterotoxigenic S. aureus, stressing the importance of strict maintenance of the cold chain.

Low prevalence of Salmonella in Swedish dairy herds highlight differences between serotypes

Legislated Salmonella control in Sweden has been in place since the 1960s. The purpose of this study was to investigate presence of Salmonella antibodies in dairy cattle herds and to provide a basis for decisions on how surveillance and control can be improved. Bulk milk samples from all Swedish dairy herds (n=4 683) were analysed with two different ELISAs; one detecting antibodies against Salmonella Dublin (Dublin ELISA), and one detecting antibodies against several of the serotypes causing bovine salmonellosis including S. Dublin (Bovine ELISA). Information about herds, i.e. geographical location, local animal density, number of test positive herds within 5km, animal trade and herd size, was based on register data.The results confirm a very low prevalence of Salmonella in Swedish dairy herds throughout the country with the exception of an island in the southeast. The test positive herds split into two groups; 41 herds (1%) positive in the Dublin ELISA, and 101 herds (2%) positive in the Bovine ELISA but negative in the Dublin ELISA. Geographical location of positive herds, and comparison of the results of the screening with serotypes previously isolated from some of the herds, indicated that the first group represents herds presently or previously infected with S. Dublin while the second group represents herds presently or previously infected with other serotypes. Differences in serological status between herds in different regions, of different size, with different animal purchase patterns et cetera, were tested using logistic regression.Presence of positive herds within 5km was significantly associated to testing positive. For herds testing positive in the Dublin ELISA, significant associations were also seen with herd size. Purchase of animals during the last year was not significantly associated with the outcome in the final models.We conclude that for future surveillance, the Bovine ELISA can be used to help in identifying infected herds, and the Dublin ELISA can be used to distinguish herds with S. Dublin infections. The geographical clustering of test positive herds could facilitate future surveillance and disease control interventions. The results highlight differences between S. Dublin and other serotypes, e.g. concerning prevalence and degree of geographical clustering. Further studies on risk factors and potential local spread of Salmonella is warranted, particularly in the regions with clustering of S. Dublin infected herds.

Frequency of Antibiotic Residues in a Central Wisconsin Dairy

Antibiotics, used to maintain healthy dairy animals, persist in milk produced by treated animals for several days after therapy. Antibiotic residues, if present in the milk supply, negatively impact suitability for processing and consumption. This is an area of concern in the dairy industry and for the general public. This study explores the incidence of antibiotic residues in milk provided to a Central Wisconsin dairy. Random, unidentified samples were obtained over a four month period from producers located within a 100-mile radius of a dairy located in Granton, Wisconsin. All samples were tested within one week of their receipt, and maintained at refrigerated temperatures at all times prior to testing. Following testing, the origin of the samples was revealed. Samples were derived from two milk populations: those intended for human consumption (bulk milk), and those from cows under surveillance following antibiotic treatment (milk removed from the commercial supply). All bulk milk samples tested negative for over 55 different antibiotic residues, while all samples from the surveillance population tested positive for antibiotic residues. Our results are consistent with those observed nationally, and suggest that dairy producers recognize the ongoing concern of antibiotic contamination in the milk supply and are taking steps to prevent antibiotic contamination in milk. Our findings also suggest the public should have minimal concern with respect to antibiotic residues in the commercial milk supply.

Circulation of a Simbu Serogroup Virus, Causing Schmallenberg Virus-Like Clinical Signs in Northern Jordan.

Schmallenberg virus (SBV)-like clinical cases of abortions in northern Jordan in early 2013, together with the emergence of SBV in Europe in 2011, its rapid spread within the following years and the detection of this virus in Turkey, raised questions about the distribution of SBV or related orthobunyaviruses. To evaluate the occurrence of SBV or related members of the Simbu serogroup of orthobunyaviruses in Jordan, bulk milk (cattle) and serum samples (cattle, sheep and goat) collected in northern Jordan in 2013 were first tested by commercially available SBV antibody ELISAs. Indeed, 3 of 47 bulk milk samples and 57 of 115 serum samples provided positive results, but SBV specificity of the ELISA results could not be confirmed by virus neutralization assays. Instead, subsequent cross-neutralization tests were able to further investigate the specificity of these antibodies. Here, a significant inhibition of Aino virus was observed. Thus, the causative agent was most likely a Simbu serogroup virus closely related to Aino virus. Consequently, these results confirm that members of this group of virus are not only present in Europe, Africa or Australia, but also in the Middle East.

Milk production, quality, and consumption in Jimma (Ethiopia): Facts and producers’, retailers’, and consumers’ perspectives

Four studies were performed to quantify milk production, quality and consumption in the town Jimma, Ethiopia. First, 47 dairy farmers and 44 milk retailers were interviewed to gain more insights in dairy farming and marketing, and associated constraints. Second, bulk milk samples (n=188) were collected for 4 consecutive weeks to investigate milk quality [Total Bacterial Counts (TBC), Coliform Counts (CC), Somatic Cell Counts (SCC), and antimicrobial residues]. Third, (bulk) milk samples from 32 farms, 46 milk retailers and the 3 local milk collection centers were collected to determine the presence of oxacillin susceptible–and oxacillin resistant Staphylococcus aureus. Fourth, 208 adult inhabitants were interviewed to gain more insight in milk consumption and associated concerns of consumers. The average dairy farm included in the studies consisted of 5 lactating cows, produced 43 liters of milk per day and was owned by male, literate adults. Milk was sold to retailers (71% of the production) and directly to customers (25%) without any quality control, whereas 4% was self-consumed. Shortage of animal nutrition and adulteration of the milk were the main constraints for farmers and retailers, respectively. The median TBC, CC and SCC were 122,500CFU/mL, 1,005CFU/mL and 609,500cells/mL, respectively. Antimicrobial residues were detected in 20% of all samples. In general, the milk quality was considered to be poor (TBC>10,000CFU/mL, and/or CC>100CFU/mL, and/or SCC>400,000cells/mL and/or presence of antimicrobial residues) in 97% of all samples. S. aureus was isolated from 12 (38%), 13 (33%), and 2 out of 3 of the milk samples originating from the dairy farms, the milk retailers, and the milk collection centers, respectively. Seven (26%) of the isolates were resistant to oxacillin suggesting the presence of MRSA (Lee, 2003). Local milk is occasionally consumed by adults but more frequently by children. Adults mainly drink spontaneously fermented milk (57% of 105 interviewees consuming local milk) whereas most milk for children is boiled (86% of 110 households with children consuming local milk). Most consumers are concerned about adulteration and milk borne diseases but not about antimicrobial residues. Educated consumers (secondary school or higher) were more likely to boil milk for own consumption, to be concerned about antimicrobial residues in milk, to be concerned about milk borne diseases and to be willing to pay more for milk with proven good quality compared to poorly educated consumers.We conclude that milk quality incentives should be introduced in Jimma, and investments should be made in knowledge transfer, training, milk collection systems and a central milk quality lab.

Case study of a commercial sheep flock under extensive mountain grazing: Pasture derived lipid compounds in milk and cheese

Terpenoid, fat-soluble antioxidant and fatty acid (FA) composition of pasture as well as those of milk and cheese from a commercial sheep flock managed under extensive mountain grazing in the east region of the Cantabrian mountain (Northern Spain) was investigated. The grazing period lasted for 2months and ewes were at late lactation stage. Plants, feces, bulk milk and cheese samples were collected on two sampling dates. The abundance of the dominating botanical families in the mountain pasture prevailed in the sheep diet of the commercial flock. Major terpenoids and tocols in the pasture appeared as major ones in milk and cheese, whereas C18 unsaturated FAs in milk and cheese were derived from the intake of C18 polyunsaturated FAs which were prevalent in the pasture. No carotene was detected in the dairy samples but retinol (free or esterified), derived from the intake of β-carotene present in pasture plants, was found in milk and cheese.

Detection of Antibiotic Resistant Staphylococcus aureus from Milk: A Public Health Implication.

The aim of this study was to investigate the occurrence, antibiotic susceptibility profiles, and virulence genes determinants of S. aureus isolated from milk obtained from retail outlets of the North-West Province, South Africa. To achieve this, 200 samples of raw, bulk and pasteurised milk were obtained randomly from supermarkets, shops and some farms in the North-West Province between May 2012 and April 2013. S. aureus was isolated and positively identified using morphological (Gram staining), biochemical (DNase, catalase, haemolysis and rapid slide agglutination) tests, protein profile analysis (MALDI-TOF mass spectrometry) and molecular (nuc specific PCR) methods. The antimicrobial resistance profiles of the isolates were determined using the phenotypic agar diffusion method. Genes encoding enterotoxins, exfoliative toxins and collagen adhesins were also screened using PCR. Among all the samples examined, 30 of 40 raw milk samples (75%), 25 of 85 bulk milk samples (29%) and 10 of 75 pasteurised milk samples (13%) were positive for S. aureus. One hundred and fifty-six PCR-confirmed S. aureus isolates were obtained from 75 contaminated milk samples. A large proportion (60%–100%) of the isolates was resistant to penicillin G, ampicillin, oxacillin, vancomycin, teicoplanin and erythromycin. On the contrary, low level resistance (8.3%–40%) was observed for gentamicin, kanamycin and sulphamethoxazole. Methicillin resistance was detected in 59% of the multidrug resistant isolates and this was a cause for concern. However, only a small proportion (20.6%) of these isolates possessed PBP2a which codes for Methicillin resistance in S. aureus. In addition, 32.7% of isolates possessed the sec gene whereas the sea, seb sed, see, cna, eta, etb genes were not detected. The findings of this study showed that raw, bulk and pasteurised milk in the North-West Province is contaminated with toxigenic and multi-drug resistant S. aureus strains. There is a need to implement appropriate control measures to reduce contamination as well as the spread of virulent S. aureus strains and the burden of disease in humans.

Effect of farm characteristics and practices on hygienic quality of ovine raw milk used for artisan cheese production in central Italy.

A survey on ovine dairy farms directly transforming own-produced milk, in the Italian Marche region, was carried out to assess flock and milking practices that may influence milk hygienic-sanitary conditions. A census survey established that 24 dairy farms were located in this region. Bulk milk samples were collected throughout the milking period in each dairy farm in 2013. Analyzed variables were: (i) chemical parameters such as fat, protein and lactose content, dry matter and pH; and (ii) total bacterial (TBC) and somatic cell counts (SCC). Chemical parameter values were in agreement with published data while, geometric mean (GM) log10 SCC was 5.91 and TBC GM was 57 978 colony forming units/mL, in compliance with Eropean Union criteria. A positive correlation was found between SCC and TBC when GMs of all farm data were considered (Spearman's rho = 0.7925; P = 0.0001). Statistical analysis did not show significant correlation between SCC or TBC GM and dairy farm principal characteristics. Although SCC levels detected in the present study should suggest the need to implement mastitis control programs, Marche's dairy sheep flocks revealed a good hygienic condition level. This is an important aspect in implementing safety for end users of the final product.

Discrimination of "grazing milk" using milk fatty acid profile in the grassland dairy area in Hokkaido.

Milk produced by the grazing system, referred to as "grazing milk" contains many components required for human health. The milk fatty acid (FA) profile is strongly associated with the diet on the farms. In the present study, based on the FA profile of farmer's bulk milk, we determined how to discriminate between milk produced on grazing and on a confinement system. A field survey was conducted four times (grazing and confinement season) in the Konsen (29 farms) and Okhotsk (25 farms) area in Hokkaido. Farmer's bulk milk samples and details of feeding management were collected and the FA profile of milk was measured. Milk produced during the grazing season contained less C16:0 and cis-9 C16:0, and more C18:0, cis-9 C18:1, trans-11 C18:1, cis-9,12 C18:2, cis-9,trans-11 C18:2 and cis-9,12,15 C18:3 than milk produced during the confinement season. Discrimination analysis using 16 FA revealed that almost all milk samples were discriminated correctly (confinement season: 90% correct and 10% borderline, grazing season: 88% correct, 9% borderline and 3% incorrect). For farmers that were categorized incorrectly and were considered borderline in the grazing season, the dependency on pasture was low compared with that for farmers correctly discriminated. Therefore, to claim "grazing milk", a high dependency on pasture is required for grazing dairy farmers.

The Sensitivity of the PCR Method for Detection of Coxiella burnetii in the Milk Samples

samples. Materials and Methods: In this cross-sectional study 70 bovine bulk milk samples were collected randomly from dairy herds in Jahrom, Iran in 2010. All the samples were analyzed for the presence of C. burnetii by PCR targeting 3 different genes (Trans, OMP, Coc). The PCR products were examined by electrophoresis using an agarose gel. Results: The frequency of C. burnetii in the evaluated samples using Trans-PCR, OMP-PCR and Coc-PCR were 17.14%, 10% and 10%, respectively. Conclusions: The results of this study show that Trans-PCR is highly sensitive and useful for the direct detection of C. burnetii in milk samples. This technique is a one-step and fast process in comparison to the other assays.

Challenges for bovine viral diarrhoea virus antibody detection in bulk milk by antibody enzyme-linked immunosorbent assays due to changes in milk production levels.

BackgroundBovine viral diarrhoea (BVD) is considered eradicated from Denmark. Currently, very few (if any) Danish cattle herds could be infected with BVD virus (BVDV). The Danish antibody blocking enzyme-linked immunosorbent assay (ELISA) has been successfully used during the Danish BVD eradication program, initiated in 1994. During the last decade, the cattle herd size has increased while the prevalence of BVDV has decreased. In this study, we investigated how these changes could affect the performance of the Danish blocking ELISA and of the SVANOVIR®BVDV-Ab indirect ELISA. The latter has successfully been used to eradicate BVD in Sweden.Data (2003–2010) on changes in median herd size and milk production levels, occurrence of viremic animals and bulk milk surveillance were analysed. Additionally, the Danish blocking ELISA and the SVANOVIR ELISA were compared analyzing milk and serum samples. The prevalence of antibody positive milking cows that could be detected by each test was estimated, by diluting positive individual milk samples and making artificial milk pools.ResultsDuring the study period, the median herd size increased from 74 (2003) to 127 cows (2010), while the prevalence of BVDV infected herds decreased from 0.51 to 0.02 %. The daily milk yield contribution of a single seropositive cow to the entire daily bulk milk was reduced from 1.61 % in 2003 to 0.95 % in 2010 due to the increased herd size. It was observed that antibody levels in bulk milk decreased at national level. Moreover, we found that when testing bulk milk, the SVANOVIR®BVDV-Ab can detect a lower prevalence of seropositive lactating cows, compared to the Danish blocking ELISA (0.78 % vs. 50 %). Values in the SVANOVIR®BVDV-Ab better relate to low concentrations of antibody positive milk (R2 = 94-98 %), than values in the blocking ELISA (R2 = 23–75 %). For sera, the two ELISAs performed equally well.ConclusionsThe SVANOVIR ELISA is recommended for analysis of bulk milk samples in the current Danish situation, since infected dairy herds e.g. due to import of infected cattle can be detected shortly after BVDV introduction, when only few lactating cows have seroconverted. In sera, the two ELISAs can be used interchangeably.

Incidence of some pathogenic microorganisms in bulk tank milk in some farms of Gharbia governorate

Milk and its products can harbor a variety of microorganisms and can be important sources of food bornepathogens. The presence of food borne pathogens in milk is due to direct contact with contaminated sourcesin the dairy farm environment and to excretion from the udder of an infected animal. The foodbornepathogens can reach humans by direct contact, ingestion of raw contaminated milk or cheese, orcontamination during the processing of milk products. Isolation of bacterial pathogens with similar biotypesfrom dairy farms and from outbreaks of human disease substantiates this hypothesis. This study wasconducted to determine the incidence of some pathogenic micro organisms in bulk tank milk from 3 dairyfarms in Gharbia governorate, Egypt. Staphylococcus aureas, Streptococcus agalactiae and Escherichiacoli were detected with percentages of 37.5, 6.25 and 12.5% in examined bulk milk samples collected fromfarm I, 25, 12.5 and 25% from farm II and 12.5, zero, and 12.5% from farm III., respectively. The presenceof these pathogenic microorganisms in bulk tank milk contribute a potential risk to public health, thesefindings underscore the need to control them and to limit bacterial multiplication in bulk tank milk

Assessment of Risk Factors in Milk Contamination with Staphylococcus aureus in Urban and Peri-Urban Small-Holder Dairy Farming in Central Ethiopia.

Assessment of risk factors associated with milk production systems is central to ensuring quality and safety of milk and milk products. This study was aimed at identifying possible risk factors in milk contamination in urban and peri-urban areas of the central high lands of Ethiopia. A total of 477 on-farm pooled milk (n = 433) and combined bulk milk samples (n = 44) were collected and processed using standard microbiological techniques to isolate and characterize Staphylococcus aureus. In addition, 433 individual farm owners and 22 collection centre owners were interviewed using a structured and pre-tested questionnaire. Multivariate logistic regression was used to determine risk factors. Of the total individual on-farm pooled milk samples analysed (n = 433), it was found that 103 of the individual milk samples (24%) and 17 of the combined bulk milk (39%) were positive for S. aureus. This difference in prevalence was statistically significant. Even though there were a number of potential variables associated with the recovery of S. aureus in bovine milk, four variables including cleaning milk container with hot water and detergent [Adjusted OR: 0.342, 95% CI, (0.166, 0.701)], mastitis check [Adjusted OR: 3.019, 95% CI (1.542, 5.913)], travel time to collection centres [Adjusted OR: 4.932, 95% CI, (2.265, 10.739)] and amount of milk delivered by farmers to collection centres per day [Adjusted OR: 1.059 (1.032, 1.087 β = 0.057)] were found to be statistically significantly associated with isolation of S. aureus. We recommend a targeted educational intervention on defined risk factors to reduce the post-harvest S. aureus contamination of raw milk in urban and peri-urban milk shed areas of central Ethiopia.

Relationship between production conditions and milk gross composition in ewe’s and goat’s organic and conventional farms in central Greece

Organic milk and dairy products are widely consumed lately, with the belief they are of higher nutritional quality than conventional, while researchers report contradictory views on this issue. This study aimed to compare the fat, protein, and lactose content of organic and conventional raw ewe’s and goat’s milk in Greece and to further associate the impact of the farming practices on these parameters. Two hundred thirty-four bulk milk samples were collected from 62 goat and 16 sheep organic and conventional farms with similar farming characteristics. A standardized detailed survey and a sampling report were used in order to record the farming practices implemented in the participating farms. The chemical composition of all samples was determined by Fourier transformed infrared analysis. Statistical associations of farming practices with the milk chemical gross composition results were explored using linear mixed-model analysis. Linear mixed-model analysis revealed several factors in farming practices such as the feeding regime, the season, and the breed to be associated with ewe’s and goat’s milk composition, while organic or conventional farm system was not identified as an associated factor. Organic and conventional goat and sheep farming in Greece does not substantially differ, and consequently, there were no significant differences found in the examined chemical composition parameters of organic and conventional goat’s and ewe’s milk.

Impact of three inactivated bovine viral diarrhoea virus vaccines on bulk milk p80 (NS3) ELISA test results in dairy herds

Bovine viral diarrhoea virus (BVDV) is endemic in many countries and vaccines are used as a component of control and eradication strategies. Surveillance programmes to detect exposure to BVDV often incorporate the use of bulk milk (BM) testing for antibodies against BVDV p80 (NS3), but vaccination can interfere with these results. The aim of this study was to evaluate whether BVDV vaccines would confound BM testing for specific antibodies in a nationally representative group of commercial dairy farms in the Republic of Ireland. A total of 256 commercial dairy herds were included in the statistical analysis. Quarterly BM or serum samples from selected weanling heifers (unvaccinated homeborn youngstock) were assessed by ELISA for antibodies against the BVDV p80 subunit and whole virus. Wilcoxon rank-sum and receiver operating characteristic (ROC) analyses were used to examine differences among groups vaccinated with one of three commercially available inactivated BVDV vaccines. Two of the three vaccines showed evidence of interference with ELISA testing of BM samples. ROC analysis highlighted that one vaccine did not reduce the discriminatory power of the BVDV p80 ELISA for identification of herds with evidence of recent BVDV circulation, when compared with unvaccinated herds; thus, administration of this vaccine would allow uncomplicated interpretation of BM ELISA test results in vaccinated seropositive herds. Seasonal differences in BM antibody results were identified, suggesting that the latter half of lactation is the most suitable time for sampling dairy herds containing predominantly spring calving cows. The results of the present study are likely to prove useful in countries allowing vaccination during or following BVDV eradication, where BM testing is required as part of the surveillance strategy.

Q fever infection in dairy cattle herds: increased risk with high wind speed and low precipitation.

Ruminants are considered the main reservoir for transmission of Coxiella burnetii (Cb) to humans. The implementation of effective control measures against Cb in ruminants requires knowledge about potential risk factors. The objectives of this study were (i) to describe the spatial distribution of Q fever-infected dairy cattle herds in Sweden, (ii) to quantify the respective contributions of wind and animal movements on the risk of infection, while accounting for other sources of variation, and (iii) to investigate the possible protective effect of precipitation. A total of 1537 bulk milk samples were collected and tested for presence of Cb antibodies. The prevalence of test-positive herds was higher in the south of Sweden. For herds located in areas with high wind speed, open landscape, high animal densities and high temperature, the risk of being infected reached very high values. Because these factors are difficult to control, vaccination could be an appropriate control measure in these areas. Finally, the cumulated precipitation over 1 year was identified as a protective factor.

Detection of Coxiella burnetii and sequencing the IS1111 gene fragment in bulk tank milk of dairy herds

Coxiella burnetii is the etiologic agent of Q fever in human. This study is aimed to determine the contamination rate of C. burnetii in bulk tank milk samples. In this study, a total number of 100 bulk milk samples collected from dairy farms in northeast of Iran and were examined for C. burnetii using touchdown PCR assay. The primers were designed to amplify a 687-bp fragment of the IS1111 gene of C. burnetii. Five samples (5%) of bovine milk were found positive for C. burnetii. Sequence analysis of PCR products revealed 100% identity with published sequences of C. burnetii in genBank. Results of this study indicate that bovine milk is an important source of C. burnetii infection in Iran.

Prevalence and seasonality of bulk milk antibodies against Dictyocaulus viviparus and Ostertagia ostertagi in Irish pasture-based dairy herds

Infections with Dictyocaulus viviparus and Ostertagia ostertagi nematode parasites are of importance to bovine health and production in temperate areas across the world. Losses due to these parasites in dairy herds can be considerable due to decreased milk productivity and fertility. However, information on current epidemiological patterns in Irish dairy herds is limited. Bulk milk samples were collected from a total of 319 dairy farms across the Republic of Ireland. The D. viviparus samples were tested with an ELISA based on recombinant major sperm protein, while the O. ostertagi samples were tested with an ELISA based on crude saline extract, whole worm O. ostertagi antigen. Management data were collected from the farms using a questionnaire. Logistic regression was used to find significant associations between the presence of antibodies against D. viviparus and O. ostertagi and management factors. The overall prevalence of D. viviparus infection was 62.8%, while over 98% of herds had antibodies to O. ostertagi at the specified cut-off. Both D. viviparus and O. ostertagi antibodies were highest in November, which could be explained by the accumulated uptake of larvae through the grazing season. In herds of farmers that dosed their in-calf heifers with anthelmintics were significantly more likely to be positive for antibodies against D. viviparus infection. This study highlights that both D. viviparus and O. ostertagi infections are widespread in dairy herds in Ireland throughout the grazing season.