Aspán, A.

Hurri, Emma

Lundberg, Å.

Ohlson, A.

Pedersen, K.

Tråven, Madeleine

English

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 This abstract was presented at the 31st World Buiatrics Congress, 2022-09-04 - 2022-09-08, Madrid, Spain  This publication is openly available through SLU publication database, https://res.slu.se/id/publ/120279. Abstract for WBC 2022, Madrid Nation-wide screening of antibodies to Mycoplasma bovis in Swedish dairy herds and herd characteristics associated with the infection Authors: Hurri E.1, 2, Ohlson A.3, Lundberg Å.3, Aspán A.2, Pedersen K.2, Tråvén M.1 1. Department of Clinical Sciences, Swedish University of Agricultural Sciences 2. Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute 3. Section of Animal health, Växa Sverige  Key words: Elisa, prevalence, risk factors, milk production, calf mortality Background Mycoplasma (M.) bovis is considered an emerging pathogen that causes severe disease in cattle in many countries and is poorly responsive to treatment. An increasing prevalence of the infection, suggested by preliminary data, may pose a threat to the Swedish favorable situation concerning antimicrobial resistance (AMR) in cattle herds.   In Sweden, M. bovis has caused severe symptoms with outbreaks of pneumonia mainly in fattening herds. Before this study, there were around 20 dairy herds and 30 fattening herds that had been diagnosed in other projects or in field work. In 2016 a national screening on bulk tank milk (BTM) was performed to determine the prevalence of M. bovis. The samples were analyzed with PCR and ten farms out of 3,473 were positive, 0.3 % (1). There are disadvantages with the use of PCR since the bacteriium is shed intermittently and milk from infected cows might not be included in the BTM at the time of sampling. Therefore, analyzing antibodies (ab) could provide a more correct prevalence of M. bovis infection in Swedish dairy herds.  Objectives The objectives of our study were to investigate the BTM prevalence of M. bovis in Swedish dairy herds by determining the presence of antibodies and M. bovis DNA and to study herd characteristics associated with a positive BTM sample.  Material & Methods Samples of BTM delivered from all dairy herds in Sweden, 3,144 herds, were obtained from the dairy routine laboratory with the help from Växa Sverige. The samples were analyzed with ID screen® indirect ELISA (IDvet, Grabels, France). High sensitivity and specificity for M. bovis antibodies in serum was recently shown for this newly developed ab ELISA (2). The samples were also analyzed with a real time PCR (PathoProof Mastitis Major 4, Thermo Fisher Scientific, Vantaa, Finland). Herd level data on health parameters were retrieved from the Dairy Herd Improvement database (Växa Sverige), for a period of 12 months prior to the BTM sampling. The association between the herd-level M. bovis antibody status (negative/positive) and each of the herd variables was first evaluated by chi-square test (χ2) for categorical variables and Student’s t-test for the continuous ones. All variables with P≤0.20 were further analysed in multivariable logistic or linear regression models, correcting for biologically plausible variables. Results BTM samples from 4.8 % of the herds were positive for antibodies to M. bovis. There were large regional differences with the proportion of ab positive herds per region ranging from 0 to 20 percent. All herds were negative on PCR analysis. For the herd characteristics there was a higher risk of antibody positivity in larger herds and there were also significant associations between antibody positivity and having a mortality of more than 0% in older calves (age 2-6 months) as well as in young stock (age 6-15 months). Moreover, there was a tendency of having a higher incidence of cows with more than 120 days between calving and final insemination in antibody positive herds compared to negative ones (P=0.052).  Conclusions This is, to our knowledge, the first time a nation-wide screening of BTM antibodies to M. bovis is presented using the ID screen® indirect ELISA. The results of this study indicate that M. bovis infections are more prevalent among Swedish dairy herds than previously recognized, and that ab ELISA may be an efficient way to detect infected herds. The association between infection status, as measured by BTM antibody ELISA, and young stock and late calf mortality suggests that M. bovis infection affects animal health and welfare in Swedish dairy herds. References 1. Landin et al, IDF mastitis conference, 2019. Prevalence of Mycoplasma bovis and Streptococcus agalactiae in Swedish dairy herds. https://www.researchgate.net/publication/333162023_Prevalence_of_Mycoplasma_bovis_and_Streptococcus_agalactiae_in_Swedish_dairy_herds 2. Andersson et al. BMC Veterinary Research (2019) 15:369. A European inter-laboratory trial to evaluate the performance of three serological methods for diagnosis of Mycoplasma bovis infection in cattle using latent class analysis.  

Nation-wide screening of antibodies to Mycoplasma bovis in Swedish dairy herds and herd characteristics associated with the infection

https://pub.epsilon.slu.se/30531/1/hurri-e-et-al-20230329.pdf

Nation-wide screening of antibodies to Mycoplasma bovis in Swedish dairy herds and herd characteristics associated with the infection

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