title: Management strategies to decrease the prevalence of mastitis caused by one strain of Staphylococcus aureus in a dairy herd.
abstract: The dairy herd at Washington State University had an outbreak of mastitis caused by a single strain of Staphylococcus aureus. The outbreak strain, termed novel, could not be controlled with routine contagious mastitis pathogen control procedures (incidence, 3.4 infections/100 cow months; peak prevalence > 22%). Our objective was to implement mastitis control measures that would decrease the incidence and prevalence of intramammary infection (IMI) caused by S aureus in the herd. The following intervention strategies were successfully implemented: strict segregation of cattle with IMI caused by S aureus, intensified culling of cattle with multiple-quarter IMI caused by S aureus, and inducing cessation of lactation of infected quarters in single-mammary-quarter infected cattle. One year after implementation of these control measures, incidence of IMI caused by S aureus was 0.35 infections/100 cow months, and prevalence had decreased from 20 to 8%.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman 99164-70601, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Middleton
authors.forename: L K
authors.initials: LK
authors.lastname: Fox
authors.forename: T H
authors.initials: TH
authors.lastname: Smith
mesh_terms: D000818:Animals; D002417:Cattle; D002452:Cell Count / Q000662:veterinary; D003612:Dairying / Q000379:methods*; D004196:Disease Outbreaks / Q000517:prevention & control / Q000662:veterinary; D018562:Disease Transmission, Infectious / Q000517:prevention & control / Q000662:veterinary; D005260:Female; D017053:Infection Control; D008321:Mammary Glands, Animal / Q000382:microbiology; D008414:Mastitis, Bovine / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control*; D008892:Milk / Q000166:cytology / Q000382:microbiology; D015995:Prevalence; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000517:prevention & control / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000145:classification / Q000302:isolation & purification*