Field Observations on the Variation of Streptococcus uberis Populations in a Pasture-Based Dairy Farm

• Published in: Journal of dairy science Vol. 90; no. 12; pp. 5558 - 5566
• Main Authors: Lopez-Benavides, M.G., Williamson, J.H., Pullinger, G.D., Lacy-Hulbert, S.J., Cursons, R.T., Leigh, J.A.
• Format: Journal Article
• Language: English
• Published: Savoy, IL Elsevier Inc 01.12.2007; American Dairy Science Association; Am Dairy Sci Assoc
• Subjects: Animal productions; Animals; Bacterial Typing Techniques - veterinary; Biological and medical sciences; Cattle; Cattle Diseases - epidemiology; Cattle Diseases - etiology; Colony Count, Microbial - veterinary; dairy cows; dairy farming; Dairying - methods; environment; Environmental Microbiology; Female; Food industries; Fundamental and applied biological sciences. Psychology; Genotype; mastitis; microbial detection; Milk and cheese industries. Ice creams; multilocus sequence typing; on-farm research; pastures; Phylogeny; Poaceae - microbiology; Risk Factors; seasonal variation; Seasons; strain differences; strains; Streptococcal Infections - epidemiology; Streptococcal Infections - etiology; Streptococcal Infections - veterinary; Streptococcus - classification; Streptococcus - genetics; Streptococcus - isolation & purification; Streptococcus uberis; Terrestrial animal productions; Vertebrates; multilocus sequence typing; Streptococcus uberis; environment; mastitis; Streptococcaceae; Mastitis; Pasture; Dairy industry; Variations; Bacteria; Micrococcales; Environment
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2007-0194

Microbiological and molecular tools were used to monitor Streptococcus uberis populations on farm tracks and paddocks on a dairy farm during different seasons of a year to identify and profile potential environmental niches of Strep. uberis in a pasture-based dairying system. Farm tracks of high or low cow traffic were sampled every 2 wk for an entire year and Strep. uberis numbers were enumerated from a selective medium. During each season of the year, paddocks were sampled for the presence of Strep. uberis before and after grazing by dairy cows. Farm tracks of high cow traffic generally had greater concentrations of Strep. uberis isolated compared with tracks with less cow traffic, but there was also significant variation in the concentrations of Strep. uberis contamination among seasons, being highest in winter and lowest in summer. The bacterium was detected in paddocks only after cow grazing had occurred, but the bacteria could still be detected in soil for up to 2 wk following grazing in winter. Multilocus sequence typing showed great heterogeneity, with some commonality between farm track and milk isolates, which may help explain cow-to-environment or environment-to-cow transmission of the bacterium in the dairy setting.