=Paper=
{{Paper
|id=Vol-2761/HAICTA_2020_paper76
|storemode=property
|title=Investigation of Subclinical Mastitis and the Role of Non-aureus Staphylococci in a Dairy Farm with Chronically Elevated Bulk Tank Milk Somatic Cell Count - Abstract
|pdfUrl=https://ceur-ws.org/Vol-2761/HAICTA_2020_paper76.pdf
|volume=Vol-2761
|authors=Konstantinos Themistokleous,Nikolaos Panousis,Georgios Arsenos,Antonios Zdragas,Efstratios Souglis,Nektarios Siachos,Georgia Koutouzidou,Theodoros Kallitsis,Evangelos Kiossis
|dblpUrl=https://dblp.org/rec/conf/haicta/ThemistokleousP20
}}
==Investigation of Subclinical Mastitis and the Role of Non-aureus Staphylococci in a Dairy Farm with Chronically Elevated Bulk Tank Milk Somatic Cell Count - Abstract==
<pdf width="1500px">https://ceur-ws.org/Vol-2761/HAICTA_2020_paper76.pdf</pdf>
<pre>
    Investigation of Subclinical Mastitis and the Role of
     Non-aureus Staphylococci in a Dairy Farm with
    Chronically Elevated Bulk Tank Milk Somatic Cell
                     Count - Abstract

  Konstantinos Themistokleous1, Nikolaos Panousis1, Georgios Arsenos1, Antonios
Zdragas2, Efstratios Souglis3, Nektarios Siachos1, Georgia Koutouzidou4, Theodoros
                            Kallitsis1, Evangelos Kiossis1
      1
       Faculty of Veterinary Medicine, School of Health Sciences, Aristotle University of
                Thessaloniki, 54124, Greece; e-mail: konsthem@vet.auth.gr
   2
    National Agricultural Research Foundation—NAGREF, Veterinary Research Institute of
                            Thessaloniki, 57001, Thermi, Greece
     3
       Dairy Department, American Farm School of Thessaloniki, 57001, Thermi, Greece
     4
      Department of Applied Informatics, University of Macedonia, 54636, Thessaloniki,
                                           Greece



Summary

   The objectives were to retrospectively evaluate subclinical mastitis (SCM) in a farm
with persistently elevated bulk tank milk (BTM) somatic cell count (SCC), and to
investigate the role of non-aureus staphylococci (NAS) among cows with chronic
SCM. The study was performed in a dairy farm with a history of chronically elevated
BTM SCC, with 120 Holsteins milked twice daily. Initially, a retrospective evaluation
of SCM was performed, based on monthly individual and BTM SCC reports, provided
by dairy herd improvement (DHI) program, from 2015 until 2018. SCC cut-off used
to determine SCM was preset at 250,000 cells/mL. Cows were grouped in DHI reports
by lactation number (1st, 2nd, ≥3rd) and stage [0-60, 61-120, 121-180, ≥181 days in
milk (DIM)], and herd as a whole. SCM prevalence was calculated as the monthly
percentage of cows over the cut-off, per herd, lactation number and stage. Chronic
SCM prevalence was calculated as the percentage of cows over the cut-off in ≥2
sequent monthly reports, per herd, lactation number and stage. A “dynamic” group of
chronically high SCC cows was created. In the second part of the study, the farm was
visited monthly during 2019 by the same team to assess the “dynamic” group and
collect samples for milk cultures. Monthly DHI reports were available for monitoring
of this “dynamic” group throughout 2019. Cows with SCC below cut-off in a new
monthly recording were removed from the “dynamic” group and new cows exceeding
cut-off in ≥2 sequent recordings entered the “dynamic” group. The retrospective
analysis (2015-2018) revealed an overall SCM prevalence of 46%. SCM prevalence
in ≥3rd lactation cows was 60%, with 87% of them being chronic cases. SCM
prevalence was noticeably high at 1st lactation cows (18%). Half of cows at late
lactation (≥181 DIM) had SCM and almost all were chronic cases. Incidence rate of
new infections at early lactation (0-60 DIM) was 4 times higher than later stages. On




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average, 8 out of 120 milking cows were responsible for more than 50% of somatic
cells in the BTM in each monthly recording in 2019. Approximately 60% of these
cows remained high SCC contributors for ≥2 months and 87% were chronic SCM
cases. Among these cows, 59% were at late lactation and 65% were in ≥3rd lactation.
Overall, 52 cows were monitored in the chronically high SCC group, either for a single
month or more. After a year of monthly milk cultures, this group was identified as
major-pathogens free (Staph. aureus, Str. uberis, Str. agalactiae and Str. dysgalactiae).
Non-aureus staphylococci (Staph. chromogenes, Staph. hyicus, Staph. warneri, Staph.
epidermidis) were involved in 44% of chronically high SCC cows, either solely (26%)
or in mixed infections (18%) with other pathogens (mainly, Corynebacterium bovis,
E. coli and Bacillus licheniformis). Infections caused solely by the latter pathogens
were 30%. In 26% of all samples no pathogen was isolated. High somatic cell
contributors in BTM were mainly cows with chronic SCM being in ≥3rd lactation and
at late lactation stage. NAS were involved in the majority of chronic SCM cases. In
compliance with literature, presence of NAS in these cows seems to play an inhibiting
role against major pathogens.

       Keywords: Dairy cows; subclinical mastitis; non-aureus staphylococci; milk
       somatic cell count.


Acknowledgements. This research has been co-financed by the European Regional
Development Fund of the European Union and Greek national funds through the
Operational Program Competitiveness, Entrepreneurship and Innovation, under the
call RESEARCH – CREATE – INNOVATE (project code: T1EDK-03989).




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