Management practices associated with presence of Staphylococcus aureus in bulk tank milk from Ohio dairy herds

Staphylococcus aureus is the most common contagious mastitis pathogen affecting cows worldwide. Practices to control this organism have been advocated for decades, and identification of risk factors in individual herds is crucial in prevention and control of Staph. aureus. The objectives of this paper were to estimate prevalence of Staph. aureus in Ohio dairies and to determine a potential association of herd characteristics and management practices with isolation of Staph. aureus in bulk tank milk. A questionnaire about herd characteristics, milking procedures, udder health, mastitis control, and biosecurity practices was mailed to 780 dairy producers; the response rate for the survey was 49%. Staphylococcus aureus prevalence was 48, 64, and 69% when 1, 2, or 3 samples of bulk tank milk from each herd were considered, respectively. Herds practicing prestrip, pre- and postmilking teat dip, and using a single towel per cow as part of the milking routine as well as herds where owners were involved in milking were at significantly reduced odds for defection of Staph. aureus in their bulk tank milk.