Bayesian latent class models to determine diagnostic sensitivities and specificities of two point of care rapid tests (Selma plus, Dipslide) for the detection of Streptococcus uberis associated with mastitis in dairy cows.

Introduction: Development and validations of accurate mastitis diagnostics are crucial to make timely and evidence-based decisions on mastitis therapy in order to reduce its impact on productivity, animal welfare and practicing the prudent use of antimicrobials on dairy farms. Methods: The objectives of this study were to assess the agreement between test results from reference laboratory and two point of care tests (Selma plus, Dipslide) and to estimate the test accuracies with Bayesian latent class models (BLCMs). In total of 509 single quarter milk samples from cows with mastitis were included in the study. Results: Among all analyzed mastitis pathogens, Streptococcus spp. was detected in up to one third of all analyzed samples and for Selma all Streptococcus samples were considered as Streptococcus uberis. The agreement (κ) when comparing two tests varied greatly depending on the bacteria, ranging from no agreement to good agreement (κ = negative to 0.86) depending on the prevalence of identified pathogens. Based on BLCMs to assess diagnostic test accuracies for the pathogen Streptococcus uberis, posterior sensitivities of 76, 71, and 64% for Selma plus, Dipslide and laboratory standard culture and specificities of 93%, 98% for Selma and Dipslide, respectively, were obtained. Discussion: The two point of care rapid culture systems Dipslide and Selma plus plate can provide important preliminary pathogen identification for targeted mastitis therapy, especially when general information about growth and a rough classification of the bacteria into groups have an impact on treatment strategy. The two evaluated rapid culture systems, Dipslide and Selma plus plate, show good test accuracies for Streptococcus uberis at least at genus level. Therefore, using these tests may contribute to prudent use of antibiotics.

Survey on the disposal of waste milk containing antimicrobial residues on Swiss dairy farms.

Feeding waste milk containing antimicrobial residues (WMA) to calves has been associated with increased antimicrobial resistance in calves' commensal bacterial flora. The objectives of this study were (1) to document practices related to the disposal of WMA on Swiss dairy farms and (2) to evaluate the association between farm characteristics and the feeding of WMA to calves. A web-based questionnaire on practices surrounding waste milk disposal was completed by 1,625 dairy producers (10.9% of solicited producers). Logistic regression models were built to evaluate the association between herd characteristics and the practice of feeding WMA. Waste milk produced during and up to the first milking after completion of antimicrobial treatment or during the withdrawal period was fed to at least some of the calves on 47.3% of respondents' farms. Farms in organic production had lower odds of feeding WMA to calves than nonorganic farms [odds ratio (OR) 0.59]. Farms located in the eastern region of Switzerland, as opposed to those in the western region, had increased odds of feeding WMA to calves (OR 2.01). A yearly average bulk tank somatic cell count ≥150,000 cells/mL was associated with increased odds of feeding WMA to calves compared with the reference category of <100,000 cells/mL (OR 1.62). An average cow-level annual milk production ≥8,500 L was associated with increased odds of feeding WMA to calves compared with farms in the interquartile range with a production of 6,500 to 8,499 L (OR 1.24). Further research is warranted to investigate dairy farmers' motivations affecting this practice, and to quantitatively define calves' exposure to antimicrobial residues and the resulting antimicrobial resistance in calves' commensal flora on these farms.

Factors associated with cattle necropsy submissions in Switzerland, and their importance for surveillance.

Pathology data have been reported to be important for surveillance, as they are crucial for correctly recognizing and identifying new or re-emerging diseases in animal populations. However, there are no reports in the literature of necropsy data being compared or complemented with other data. In our study, we compared cattle necropsy reports extracted from 3 laboratories with the Swiss fallen stock data and clinical data collected by the association of Swiss Cattle Breeders. The objective was to assess the completeness, validity and representativeness of the necropsy data, as well as evaluate potential factors for necropsy submission and how they can benefit animal health surveillance. Our results showed that, on average, 1% of Swiss cattle that die are submitted for post-mortem examinations. However, different factors influence cattle necropsy submissions, such as the age of the animal, the geographical location and the number of sick and/or dead animals on the farm. There was a median of five animals reported sick and two animals reported dead within 30 days prior to a necropsy submission, providing quantitative evidence of a correlation between on farm morbidity/mortality and post-mortem examination. Our results also showed that necropsy data can help improve the accuracy and completeness of health data for surveillance systems. In this study, we were able to demonstrate the importance of veterinary pathology data for AHS by providing quantitative evidence that necropsied animals are indicative of farms with important disease problems and are therefore critically important for surveillance. Furthermore, thanks to the amount of information provided by combined data sources, the epidemiology (e.g. season, geographic region, risk factors) of potential diseases can be analysed more precisely and help supporting animal health surveillance systems.

Swiss Dairy Farmers' Perceptions Surrounding the Disposal of Waste Milk Containing Antibiotic Residues and Antibiotic Resistance.

The feeding of waste milk containing antibiotic residues (WMA) to calves has been associated with the shedding of antibiotic-resistant bacteria by calves. However, little is known regarding farmers' intrinsic factors affecting this practice, and on which it would be relevant to intervene in order to change this practice. The objectives of this study were (1) to describe the farmers' intrinsic factors, such as perceived benefits, risks, and social norms related to the feeding of WMA to calves, antibiotic resistance, and antibiotic use, and (2) to evaluate how the feeding of WMA to calves is related to farmers' personal values and perceptions related to WMA feeding and antibiotic resistance. Answers to an online survey were collected from 233 Swiss dairy producers (38.3% response rate). The proportion of respondents who fed WMA to calves was 48.3%. In a hierarchical logistic regression model, only perception factors extracted by factor analysis were associated with the feeding of WMA to calves, namely (in decreasing order of magnitude): farm-level benefits of WMA feeding, the interaction of farm-level benefits with support from governmental authorities, and causes and threats of antibiotic resistance. The results suggest that, in order to reduce the feeding of WMA to calves, communications to dairy producers should focus on changing the perceived benefits of this practice in comparison to those of alternative WMA disposal methods carrying a lower risk of antibiotic resistance. The involvement of veterinarians and governmental authorities in these communications and in supporting producers may increase the successful adoption of alternative WMA disposal methods.

Antimicrobial consumption: Comparison of three different data collection methods.

The increasing incidence of antimicrobial resistance represents a global threat. As a result, surveillance programmes monitoring antimicrobial consumption and resistance in animals have been implemented in several countries throughout the world. However, such programmes depend on the accurate and detailed collection of data on antimicrobial consumption. For this reason, the aim of this longitudinal study was to compare the consistency of data on antimicrobial consumption between three different data collection methods. Antimicrobial consumption data associated to udder health were collected from 20 veterinary practices and 92 dairy farms for 18 months. The compared data sources were: 1) data extracted from veterinary practice software 2) farm treatment journals and 3) on-farm discarded drug packages (garbage). Two different procedures were chosen to analyse the data issued from treatment journals: 1) only complete entries were analysed 2) entries with missing dosage were supplemented with the information provided by the Swiss Compendium of Veterinary Medicinal Products. The antimicrobial data were divided into intramammary preparations used during lactation (IMM), intramammary preparations used for dry off (DRY) and systemic treatments (SYS). We compared the quantities of injectors (IMM and DRY), the quantities of active substances (SYS) and the treatment incidences (TI) for the defined daily dose (DDD) per 1000 cow-days (IMM and SYS) and the defined course dose (DCD) per 1000 cow-days (DRY). Additionally, the variety of antimicrobial products among the different data sources was compared. The highest quantity of antimicrobials for IMM, DRY and SYS could be collected with the software data. The lowest quantity was collected by using the data of the treatment journal with only complete entries. For IMM and DRY, software and garbage performed similar, with agreement on the number of injectors used in 56.1% of the analysed cases. The widest variety of intramammary antimicrobial preparations was found in the garbage whilst most systemic preparations were collected using software data. The results of the study show a lack of data consistency between the three different data sources. None of the methods was able to collect the integral antimicrobial consumption in the participating farms. Finally, the results emphasise the need to implement a standardised system to quantify and assess the antimicrobial consumption at veterinary practice and farm level.

Decision-Making of Swiss Farmers and the Role of the Veterinarian in Reducing Antimicrobial Use on Dairy Farms.

The reduction of antimicrobials on dairy farms is a topical issue and confronts both veterinarians and farmers with major challenges. The aim of this study was to investigate dairy farmers' motivation to reduce antimicrobial use on their farms. Factors influencing dairy farmers' decision-making regarding dairy cow health were identified and the role of the veterinarian in these processes was characterized. A customized structured questionnaire was sent to all participants (n = 59) of an ongoing antimicrobial reduction project among dairy farmers in the Canton of Fribourg, Switzerland, by mail. Fifty-eight completed questionnaires were returned and evaluated (response rate 98.3%). The majority of respondents were men (56/58, 96.6%) and farm managers (55/57, 96.5%) managing their farms as their main occupation (56/57, 98.2%). Using a 5-point-Likert-scale (1 = not a reason, 5 = very important reason), respondents ranked "My veterinarian is putting pressure on us to use less antimicrobials" (median=2.5, interquartile range = 1-3) and "Other farmers also reduce antimicrobial use" (2.0, 1-3) as the least important factors affecting their motivation to reduce the use of antimicrobials in dairy cows (P < 0.001). Respondents ranked their veterinarian's opinion (4.0, 4-5) and their own feelings and knowledge (4.0, 3-4) as the two factors having significantly more importance on their decisions regarding dairy cow management (P < 0.001). The farmers indicated they were satisfied with the quality of the consultancy given by their veterinarians (4.0, 4-5) and with the quality of communication with veterinarians (4.0, 3-4). They indicated that they understood recommendations made by the veterinarian (4.0, 3.75-4) and also felt understood by the veterinarian (4.0, 3-4). However, only 25.9% (14/54) indicated they were willing to pay for good quality, farm-adapted consulting by their veterinarian. Based on these findings, veterinarians play an important role in influencing Swiss dairy farmers in decision-making concerning animal health and treatment. However, veterinarians were not viewed by farmers as important motivators for reducing antimicrobial use. Swiss veterinarians are encouraged to be aware of their influence on farmers' decisions and to use that influence to more clearly promote antimicrobial reduction on dairy farms.

Knowledge, attitude and practices of Swiss dairy farmers towards intramammary antimicrobial use and antimicrobial resistance: A latent class analysis.

Understanding farmers' mindsets is important to improve antimicrobial stewardship in the dairy industry. This cross-sectional study aimed to determine farmers' knowledge, attitude, and practices with respect to lactational intramammary antimicrobial use (AMU) and antimicrobial resistance (AMR) in Swiss dairy herds. Based on their approach towards subclinical mastitis (SCM) and non-severe cases of clinical mastitis (CM), subgroups of farmers were identified and compared regarding their knowledge, attitude and practices towards AMU and AMR. After conducting qualitative interviews to develop a questionnaire, an online survey was sent to 1296 randomly selected Swiss dairy farmers. Information was gathered on demographic data and farmers' knowledge, attitude, and practices towards AMU and AMR. A latent class analysis was performed to identify subgroups of farmers based on management of SCM and non-severe CM cases. Based on the results of 542 completed questionnaires, poor knowledge with respect to AMU and AMR was identified, as well as discrepancies between farmers' perceptions and their actual practices. Farmers approached cows with SCM and non-severe CM similarly, indicating they perceived both mastitis states as the same disease. Intramammary antimicrobial products containing cefquinome, which is a highest priority critically important antimicrobial, were among the 3 most commonly applied intramammary antimicrobials. Five latent classes of farmers were identified based on their management towards SCM and non-severe CM. One group of farmers (18.5% of respondents) indicated that they did not treat those mastitis cases, one group only treated SCM cases (13.8% of respondents), one group only treated non-severe CM cases (28.6% of respondents) and the largest group treated both mastitis states (39.1% of respondents). The latter group was subdivided into a latent class of farmers following guidelines for AMU/AMR (25.5% of respondents) and a group of farmers that were not strictly following these guidelines (13.7% of respondents). Regional differences between farmers, according to altitude and language region, explained some of the variation in latent class membership. Latent class membership was associated with farmers' attitude to use antimicrobials as little as possible and with using antimicrobials only after performing bacteriological and susceptibility testing. This study gave detailed insight into Swiss farmers' knowledge, attitude, and practices regarding AMU and AMR and provides opportunities to improve antimicrobial stewardship in Swiss dairy herds. The identified groups of farmers, based on their management practices regarding SCM and non-severe CM, may help to design tailored intervention strategies for improving prudent AMU in the heterogeneous population of dairy farmers in Switzerland.

Evaluation of an investigative model in dairy herds with high calf perinatal mortality rates in Switzerland.

The objective of this study was to evaluate an investigative model which encompassed the risk factors, incidence, timing and causes of perinatal mortality (PM) (0-48 h) on high risk dairy farms (PM of >5% in the previous year) in Switzerland. This pilot-study was carried out on 47 predominantly Holstein PM calves from 21 dairy farms, between September 2016 and January 2018. Gross pathological examinations of calves and placentae as well as histopathological examinations of internal organs and placental tissue were performed. Further investigations included microbiological examinations: broad-spectrum bacterial and fungal culture, detection of Chlamydia abortus, Coxiella burnetii, pathogenic Leptospira spp. and Neospora caninum by real-time PCR (qPCR) and of bovine viral diarrhoea virus (BVDV) by Ag-ELISA. Maternal blood samples were used for serology of bovine herpesvirus 1 (BHV-1), Brucella abortus, Chlamydia abortus, Coxiella burnetii and nine pathogenic leptospiral serovars and the evaluation of trace element status. A questionnaire was completed with the farmer, which included general farm characteristics and case-related data. Inbreeding coefficients (IC) were calculated for pure-bred matings. At the farm-level, the PM rate was 10.0% (5.3-28.2%) and at the cow-level, 11.5%. These values, from high-risk farms, were approximately five-times higher than the contemporary national bovine PM rate (2.3%) in Switzerland. The risk factors associated with these high PM rates were the self-selection of high risk herds, the high proportion of primiparae in these herds (45%) and the evidence of widespread pathogenic infections on these farms (exposure: 67% of herds, 53% of dams; infection: 57% of herds, 45% of calves). The majority (68.1%) of calves died intrapartum. The most commonly diagnosed initiating/ultimate cause of death (UCOD) was infection (34%) of which Coxiella burnetii was the most frequently detected pathogen, by antigen. The most frequently diagnosed proximate cause of death (PCOD) was asphyxia (44.7%), though multiple PCOD was also common (21.3%). This study was the first detailed investigation of bovine PM in Switzerland. Infectious causes were diagnosed more frequently than expected. While the findings from these high PM Swiss herds may have limited external validity, the investigative model adopted and the detailed research methodologies employed can be replicated and re-evaluated, respectively, in future studies on PM internationally.

Reducing Antimicrobial Use by Implementing Evidence-Based, Management-Related Prevention Strategies in Dairy Cows in Switzerland.

The aim of this study was to reduce antimicrobial use (AMU) on dairy farms that implemented evidence-based management strategies. The study not only examined whether these strategies led to a reduction in AMU in practice, but also examined the influence of the level of their implementation on AMU. For data analysis, practice software recordings of the farm veterinarians were used. The AMU data of 50 farms with prevention strategies applied (intervention group, IG) over 3 years (2017-2019) and of 74 farms without prevention strategies (control group, CG) over 2 years (2018-2019) were analyzed. Project participation was supported with 500 Swiss francs (~545 USD) per farmer per year. The AMU was compared between the IG and CG using the treatment incidence. In December 2017/January 2018, the farmers of the IG had chosen at least one of the proposed 17 prevention strategies from one of three sectors, i.e., udder health, uterine health and/or replacement calf health. The prevention strategies, were developed in a standard operating procedure protocol and were discussed in detail with the farmers before the implementation. Forty-eight farms chose at least one udder strategy, 10 farms at least one uterine strategy and 37 farms at least one calf strategy. By choosing an udder health strategy or a uterine health strategy, the corresponding systemically administered AMU could be significantly reduced (p < 0.04) in the IG compared with the CG. In addition, udder strategies that were well-implemented led to a significant reduction (p = 0.05) of intramammary "highest priority critically important antimicrobials (HPCIA)" (quinolones, cephalosporins 3rd and higher generation, macrolides and ketolides, glycopeptides, and polymyxins). The level of implementation was significantly lower in 2019 compared to 2018 (p < 0.05, Fisher's exact test). No significant reduction in AMU could be achieved for the calf sector. A reduction of AMU in dairy farms is possible by implementing evidence-based management-related prevention strategies. The level of implementation has only an influence on the consumption of HPCIA. The reduction of AMU in practice by means of evidence-based measures requires supportive human resources instead of financial support, because financial support for farmers seems not to motivate them sufficiently.

Veterinary peer study groups as a method of continuous education-A new approach to identify and address factors associated with antimicrobial prescribing.

Within the dairy industry, most antimicrobials are used for dry-cow therapy or mastitis treatment. To reduce antimicrobial usage in dairy cows, increasing awareness and behaviour change is necessary. As veterinarians are known to be influenced by their peers, peer study groups as a continuous education might contribute to this. Therefore, the objective of this study was to analyse written records of veterinary peer study group meetings to identify factors associated with antimicrobial prescribing decisions, and to analyse veterinarians' attitude towards the benefits of this continuous education method. Twenty-three participating Swiss cattle practitioners were divided into three groups. Each group met every two to five months, together with a facilitator and an expert on the topic to be discussed. Written records from every meeting were taken and analysed qualitatively to identify factors influencing veterinarians' decisions on antimicrobial prescribing and mastitis therapy. In addition, focus group discussions were conducted after the last meeting, to assess the veterinarians' learning achievements gained during the peer study group meetings. Extrinsic factors such as external pressure, competition, farmer, individual animal, farm and diagnostics as well as intrinsic factors such as own experience/attitude, knowledge and change of mindset during career could be shown to influence veterinarians' decisions on antimicrobial prescribing. In the focus group discussions, the veterinarians stated that they gained new knowledge, received new stimuli, exchanged with their peers and felt supported in their relationship to their farmers. Since the identified factors are partly interrelated, it is not sufficient to change a single factor to achieve a change in the antimicrobial prescription behaviour of veterinarians. Veterinary peer study groups could contribute to the intention to change, because veterinarians experienced multiple benefits from this method of continuous education. In order to quantify this, the prescription data of the veterinarians are analysed in a next step.

Non-aureus Staphylococci Species in the Teat Canal and Milk in Four Commercial Swiss Dairy Herds.

Non-aureus staphylococci (NAS) are frequently found in milk samples as well as on the teat apex and in the teat canal and are known to be a cause of subclinical mastitis. The objective of this study was to investigate the relationship between NAS species colonizing the teat canal and those causing intramammary infection (IMI) in four commercial dairy herds. Teat canal swabs were obtained and thereafter milk samples were aseptically collected and evaluated for the presence of staphylococci using selective agar plates. Species identification was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The relationship between NAS species distribution and sample type (teat canal vs. milk samples) was quantified using hierarchical multivariable logistic regression models. The most prevalent NAS species in teat canal swabs were S. xylosus (35%), S. vitulinus (10%), and S. chromogenes (7%), whereas in milk samples S. chromogenes (5%), S. xylosus (5%), and S. haemolyticus (4%) were most prevalent. There were significantly higher odds for S. vitulinus (OR = 215), S. xylosus (OR = 20), S. sciuri (OR = 22), S. equorum (OR = 13), and S. succinus (OR = 10) to be present in teat canal swabs than in milk samples. Differences between herds in NAS species distribution were found and were most pronounced for S. succinus and a S. warneri-like species. This information aids in the understanding of NAS species as an etiology of IMI and should be taken into account when interpreting milk culture results.

Control of Staphylococcus aureus in dairy herds in a region with raw milk cheese production: farmers' attitudes, knowledge, behaviour and belief in self-efficacy.

BACKGROUND: Contagious mastitis is an important disease in dairy cattle, and the causative agent S. aureus can also impair raw milk cheese quality. In a confined region in eastern Switzerland attitude, knowledge and behaviour towards S. aureus und S. aureus control was assessed in 90 dairy farmers with communal alpine pasturing including raw milk cheese production with the aid of a questionnaire. RESULTS: Forty-three out of 90 questionnaires were returned (48% return rate). Farmers perceived reproductive problems as most important in their dairy herds followed by respiratory disease and diarrhoea in young stock. Most frequently stated as important motivating factors to participate in S. aureus control were "avoiding negative news about cheese quality in the press" followed by "I want to be proud of my somatic cell counts again". Most frequently chosen and identified as important constraining factors were "I fear that the authorities dictate and the farmers are not heard" followed by "costs to control S. aureus are too high because of premature culling" and "I am afraid to be forced to cull genetically valuable cows". Farmers with an experience of a S. aureus problem in their dairy herds had a significantly better knowledge about contagiosity and clinical manifestation of different S. aureus genotypes than farmers with no self-reported experience of a S. aureus problem. Veterinarians were indicated as the most important experts, farmers seek advice in case of mastitis and most farmers suggested subsidising bacteriological milk analysis as an incentive to motivate farmers towards S. aureus control. CONCLUSION: According to the results an improved knowledge transfer on S. aureus to dairy producers and an integrative approach to a S. aureus control program with subsidising milk analysis will be most promising to improve the S. aureus situation in this confinded region of eastern Switzerland. Veterinarians should cover a key role in consulting farmers during the control program.

A longitudinal study on transmission of Staphylococcus aureus genotype B in Swiss communal dairy herds.

Staphylococcus aureus is a common mastitis causing pathogen of dairy cattle. Several S. aureus genotypes exist, of which genotype B (GTB) is highly prevalent in Swiss dairy herds. Dairy farming in mountainous regions of Switzerland is characterised by the movement of dairy cattle to communal pasture-based operations at higher altitudes. Cows from different herds of origin share pastures and milking equipment for a period of 2 to 3 months during summer. The aim of this longitudinal observational study was to quantify transmission of S. aureus GTB in communal dairy operations. Cows (n=551) belonging to 7 communal operations were sampled at the beginning and end of the communal period. Transmission parameter ß was estimated using a Susceptible-Infectious-Susceptible (SIS) model. The basic reproduction ratio R0 was subsequently derived using previously published information about the duration of infection. Mean transmission parameter ß was estimated to be 0.0232 (95% CI: 0.0197-0.0274). R0 was 2.6 (95% CI: 2.2-3.0), indicating that S. aureus GTB is capable of causing major outbreaks in Swiss communal dairy operations. This study emphasized the contagious behaviour of S. aureus GTB. Mastitis management in communal dairy operations should be optimized to reduce S. aureus GTB transmission between cows and back to their herds of origin.

A dominant lineage of Mycoplasma bovis is associated with an increased number of severe mastitis cases in cattle.

Mycoplasma bovis is the most frequent etiologic agent of bovine mycoplasmosis. It causes various diseases in bovines and considerable economic loss due to the lack of effective treatment or preventive measures such as vaccination. In contrast to the US, where M. bovis-mastitis has been reported for a long time, M. bovis infections in Switzerland and Austria were predominantly associated with pneumonia and subclinical mastitis. However, since 2007 the situation has changed with the emergence of severe M. bovis-associated mastitis cases in both countries. In order to evaluate the molecular epidemiology of the bacteria isolated from these infections, recent and old Swiss, along with recent Austrian M. bovis isolates were analyzed by a typing method displaying intermediate resolution of evolutionary relationships among isolates called Multi-Locus Sequence Typing (MLST). The analysis of Swiss and Austrian M. bovis isolates revealed two major lineages. Isolates collected since 2007 in both countries cluster in the lineage I including ST5, ST33, ST34, 36, and ST38-40 (clonal complex 1), while all Swiss isolates recovered before 2007 cluster in the lineage II comprising ST17 and ST35 (clonal complex 5). Further investigations are necessary to understand if lineage I has a higher predilection or virulence toward mammary gland cells than the old lineage or if other factors are involved in the increased number of severe mastitis cases.

Mycoplasma bovis infections in Swiss dairy cattle: a clinical investigation.

Mycoplasma bovis causes mastitis in dairy cows and is associated with pneumonia and polyarthritis in cattle. The present investigation included a retrospective case-control study to identify potential herd-level risk factors for M. bovis associated disease, and a prospective cohort study to evaluate the course of clinical disease in M. bovis infected dairy cattle herds in Switzerland. Eighteen herds with confirmed M. bovis cases were visited twice within an average interval of 75 d. One control herd with no history of clinical mycoplasmosis, matched for herd size, was randomly selected within a 10 km range for each case herd. Animal health data, production data, information on milking and feeding-management, housing and presence of potential stress- factors were collected. Composite quarter milk samples were aseptically collected from all lactating cows and 5% of all animals within each herd were sampled by nasal swabs. Organ samples of culled diseased cows were collected when logistically possible. All samples were analyzed by real-time polymerase chain reaction (PCR). In case herds, incidence risk of pneumonia, arthritis and clinical mastitis prior to the first visit and incidence rates of clinical mastitis and clinical pneumonia between the two visits was estimated. Logistic regression was used to identify potential herd-level risk factors for M. bovis infection. In case herds, incidence risk of M. bovis mastitis prior to the first visit ranged from 2 to 15%, whereas 2 to 35% of the cows suffered from clinical pneumonia within the 12 months prior to the first herd visit. The incidence rates of mycoplasmal mastitis and clinical pneumonia between the two herd visits were low in case herds (0-0.1 per animal year at risk and 0.1-0.6 per animal year at risk, respectively). In the retrospective-case-control study high mean milk production, appropriate stimulation until milk-let-down, fore-stripping, animal movements (cattle shows and trade), presence of stress-factors, and use of a specific brand of milking equipment, were identified as potential herd-level risk factors. The prospective cohort study revealed a decreased incidence of clinical disease within three months and prolonged colonization of the nasal cavity by M. bovis in young stock.

Evaluation of PCR electrospray-ionization mass spectrometry for rapid molecular diagnosis of bovine mastitis.

Bovine mastitis, an inflammatory disease of the mammary gland, is one of the most costly diseases affecting the dairy industry. The treatment and prevention of this disease is linked heavily to the use of antibiotics in agriculture and early detection of the primary pathogen is essential to control the disease. Milk samples (n=67) from cows suffering from mastitis were analyzed for the presence of pathogens using PCR electrospray-ionization mass spectrometry (PCR/ESI-MS) and were compared with standard culture diagnostic methods. Concurrent identification of the primary mastitis pathogens was obtained for 64% of the tested milk samples, whereas divergent results were obtained for 27% of the samples. The PCR/ESI-MS failed to identify some of the primary pathogens in 18% of the samples, but identified other pathogens as well as microorganisms in samples that were negative by culture. The PCR/ESI-MS identified bacteria to the species level as well as yeasts and molds in samples that contained a mixed bacterial culture (9%). The sensitivity of the PCR/ESI-MS for the most common pathogens ranged from 57.1 to 100% and the specificity ranged from 69.8 to 100% using culture as gold standard. The PCR/ESI-MS also revealed the presence of the methicillin-resistant gene mecA in 16.2% of the milk samples, which correlated with the simultaneous detection of staphylococci including Staphylococcus aureus. We demonstrated that PCR/ESI-MS, a more rapid diagnostic platform compared with bacterial culture, has the significant potential to serve as an important screening method in the diagnosis of bovine clinical mastitis and has the capacity to be used in infection control programs for both subclinical and clinical disease.

Acute and chronic pain in calves after different methods of rubber-ring castration.

The goal of the present study was to evaluate the effect of different methods of rubber-ring castration on acute and chronic pain in calves. Sixty-three 4-6 week-old calves were randomly and sequentially allocated to one of five groups: Group RR (traditional rubber ring castration); group BRR (combination of one rubber ring with Burdizzo); group Rcut (one rubber ring applied with the scrotal tissue and rubber ring removed on day 9); group 3RR (three rubber rings placed one above the other around the scrotal neck); and group CO (controls; sham-castrated). All calves received 0.2 mL/kg bodyweight lidocaine 2%, injected into the spermatic cords and around the scrotal neck 15 min before castration. The presence of acute and chronic pain was assessed using plasma cortisol concentrations, response to palpation of scrotal area, time from castration until complete wound healing, and behavioural signs. Calves of group 3RR showed severe swelling and inflammation, and licking of the scrotal area occurred significantly more often than in groups Rcut and CO. Technique 3RR was discontinued for welfare reasons before the end of the study. All castration groups had significantly more pain upon palpation than calves of group CO, but palpation elicited markedly less pain in group Rcut than in the other castration groups. The most rapid healing time and shortest duration of chronic pain after castration was achieved in group Rcut. For welfare reasons, the Rcut technique should be considered as a valuable alternative to traditional rubber ring castration of calves at 4-6 weeks of age.

Herd-specific strains of Mycoplasma bovis in outbreaks of mycoplasmal mastitis and pneumonia.

Mycoplasma bovis causes severe economic losses in livestock production, particularly on the Northern American continent and more recently also in continental Europe. The aim of the current study was to evaluate whether the recently emerging outbreaks were due to a particular clone or strain of M. bovis or whether these outbreaks are due to multiple infectious strains of M. bovis. The study is based on the analysis M. bovis isolated from cattle of herds with outbreaks of mycoplasmal mastitis or pneumonia from geographically non related parts of Switzerland. M. bovis isolates were typed by insertion sequence (IS) element analysis based upon ISMbov1 and ISMbov2 southern-blot hybridization. We observed a strong divergence of M. bovis strains among affected herds which mostly were herd specific. This argues against the assumption that a recent infiltration of a particular clone of M. bovis is the cause of the perilous emerging outbreaks. The study suggests that transmission occurs from animal to animal most probably via milk.