Cross‐sectional study of Streptococcus species in quarter milk samples of dairy cows in the canton of Bern, Switzerland

Abstract

A total of 2538 quarter milk samples from 638 lactating dairy cows from 47 farms in the canton of Bern, Switzerland, were investigated for streptococci. A novel, simple and inexpensive laboratory method was used for the differentiation of Streptococcus species, and a risk factor analysis was carried out. The prevalence in the quarter milk samples was 0.2 per cent for Streptococcus agalactiae, 1.3 per cent for Streptococcus uberis, 1.3 per cent for Streptococcus dysgalactiae, 0.1 per cent for Enterococcus species and 2.9 per cent for minor Streptococcus species (designated Streptococcus-Lactococcus-Enterococcus [SLE] group). Based on the somatic cell count (SCC), S uberis and S dysgalactiae were classified as 'major' pathogens and the bacteria in the SLE group as 'minor' pathogens. For S uberis, S dysgalactiae and bacteria in the SLE group, the most significant risk factor was an intramammary infection (IMI) of a neighbouring quarter by the same pathogen. Other significant risk factors for S uberis infection were a positive California Mastitis Test (CMT) result and a SCC of more than 100,000 cells/ml. Significant risk factors for IMI with S dysgalactiae were a positive CMT result, teat injury and palpable abnormalities in the udder. Infection with bacteria in the SLE group was significantly associated with a SCC of more than 100,000 cells/ml, a lactation number of more than 2, the right rear quarter (as the location of infection) and a positive CMT result.

Etiological agents of bovine mastitis in Poland

“…These microorganisms were also isolated in our previous study (18). The results are in agreement with the data reported by other authors, although percentages of each species sometimes differ fundamentally (2,8,10,24,25,31).…”

“…Environmental streptococci have been cultured from the mouth, teat, abdomen and udder skin, bovine faeces and from straw bedding of cattle (5). The occurrence of mammary gland inflammation caused by contagious pathogen S. agalactiae has decreased over the last few decades due to introduction of mastitis control programmes (16,18) and has been almost eradicated (0-0.2%) from dairy herds in many countries (4,8,23). Recently, in some European countries such as Denmark and Finland the frequency of S. agalactiae isolation from bovine mastitis milk has increased again (1).…”

Phenotypic and genotypic identification of streptococci and related bacteria isolated from bovine intramammary infections

“…agalactiae are important mastitis pathogens whereas the remaining PNC are less frequently observed or nonpathogenic. Thus, it appears reasonable, at least for the situation observed in Swiss farms, to focus the diagnostics on these 3 major PNC pathogens [8]. …”

“…uberis , a high prevalence has been reported throughout the world [6,7], IMI caused by Strep. agalactiae has been rarely observed during the last decades in Switzerland, likely because it can be controlled by improved milking management and it shows good susceptibility to antibiotics [8]. A recent publication, however, suggests that Strep.…”

Questionnaire-based study to assess the association between management practices and mastitis within tie-stall and free-stall dairy housing systems in Switzerland

“…The reason for this association is difficult to explain. However, a risk factor analysis carried out previously in Switzerland for Streptococci species in quarter milk samples showed that S. uberis is significantly less prevalent on farms on mountainous production zones while, S. dysgalactiae is more prevalent [24]. These differences in bacterial species could explain why the ICM differs with the type of production zone.…”