This study was designed to identify risk factors for intramammary infections with @entity8211 and @entity794 under field conditions. An 18-mo survey with sampling of all quarters of all lactating @entity291 at 3-wk intervals was carried out in three Dutch dairy herds with medium bulk milk somatic cell count (200,000 to 300,000 cells/ml). Quarter milk samples were used for bacteriology and somatic cell counting. Data on parity, lactation stage, and @entity4377 -serology were recorded for each animal. During the last year of the study, body condition score, and teat-end @entity15261 scores were recorded at 3-wk intervals. A total of 93 new infections with Strep. uberis were detected in 22,665 observations on quarters at risk for @entity281 with Staph. aureus were detected in 22,593 observations on quarters at risk for Staph. @entity281 . Multivariable Poisson regression analysis with clustering at herd and @entity291 level was used to identify risk factors for @entity281 . Rate of @entity281 with Strep. uberis was lower in first- and second-parity @entity291 than in older @entity291 , and depended on stage of lactation in one herd. Quarters that were infected with @entity1679 or enterococci, quarters that had recovered from Strep. uberis- or Staph. @entity281 in the past, and quarters that were exposed to another Strep. uberis infected quarter in the same @entity291 had a higher rate of @entity281 . Teat-end @entity15261 and @entity281 with coagulase-negative staphylococci or corynebacteria were not significant as risk factors. Rate of Staph. @entity281 was higher in @entity4377 -seropositive @entity291 , in right quarters, in quarters that had recovered from Staph. aureus or @entity281 , in quarters exposed to other Staph. aureus infected quarters in the same @entity291 , and in quarters with extremely callused teat ends. Infection with coagulase-negative staphylococci was not significant as a risk factor. The effect of @entity281 with corynebacteria on rate of @entity281 with Staph. aureus depended on herd, stage of lactation, and teat-end roughness. Herd level prevalence of Strep. uberis or Staph. aureus, and low quarter milk somatic cell count were not associated with an increased rate of @entity281 for Strep. uberis or Staph. aureus.

@entity291 - and quarter-level risk factors for XXXX and @entity794 mastitis.

@entity4377 :: ('10385', 'Species') :: ['bovine herpesvirus 4'] @entity1679 :: ('1661', 'Species') :: ['Arcanobacterium pyogenes'] @entity794 :: ('1280', 'Species') :: ['Staphylococcus aureus'] @entity281 :: ('MESH:D007239', 'Disease') :: ['Strep. uberis infection', 'infection', 'aureus infection', 'aureus-infection', 'Strep. uberis infection, and 100 new infections'] @entity15261 :: ('MESH:D002145', 'Disease') :: ['callosity'] @entity8211 :: ('1349', 'Species') :: ['Streptococcus uberis'] @entity291 :: ('9913', 'Species') :: ['cows', 'cow']
@entity8211 :: (1349,Species) :: ['Streptococcus uberis']
