title: Coagulase-positive Staphylococcus intramammary infections in primiparous dairy cows.
abstract: Objectives were to determine the prevalence of coagulase-positive staphylococcal IMI in primiparous cows at first parturition, to contrast the differences in coagulase-positive staphylococcal IMI in primiparous cows at parturition in herds with high and low prevalences of coagulase-positive staphylococcal IMI in the lactating herd, and to determine the percentage of primiparous cows having persistent coagulase-positive staphylococcal IMI. Milk samples were collected aseptically from cows at the start and end of the study, at dry-off, and at parturition. Herds (n = 18) were split evenly into two categories: high (> 10%) or low (< 5%) prevalence of coagulase-positive staphylococcal IMI. At the start, the mean prevalence of coagulase-positive staphylococcal IMI in high prevalence herds was 30%, ranging from 13 to 65%, and in low prevalence herds was 2%, ranging from 0 to 5%. Overall the prevalence of coagulase-positive staphylococcal IMI in primiparous cows at parturition was 8.1% (67 of 828), ranging from 0 to 27%. Although primiparous cows from high prevalence herds had a higher prevalence of coagulase-positive staphylococcal IMI (9.2%; 40 of 436) at parturition than did primiparous cows from low herds (6.9%; 27 of 392), the difference was not significant. Of primiparous cows with coagulase-positive staphylococcal IMI at parturition, 43% had coagulase-positive staphylococcal IMI at least 2 mo after parturition. Primiparous cows with coagulase-positive staphylococcal IMI at parturition may represent significant reservoirs of infection to uninfected herdmates.
authors.affiliation: Department of Veterinary Clinical Sciences, Washington State University, Pullman 99164-6610.
authors.forename: J R
authors.initials: JR
authors.lastname: Roberson
authors.forename: L K
authors.initials: LK
authors.lastname: Fox
authors.forename: D D
authors.initials: DD
authors.lastname: Hancock
authors.forename: C C
authors.initials: CC
authors.lastname: Gay
authors.forename: T E
authors.initials: TE
authors.lastname: Besser
mesh_terms: D000818:Animals; D002417:Cattle; D003030:Coagulase / Q000032:analysis*; D005260:Female; D007743:Labor, Obstetric; D008414:Mastitis, Bovine / Q000382:microbiology*; D010298:Parity; D011247:Pregnancy; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000201:enzymology / Q000302:isolation & purification*
chemical_list: D003030:Coagulase