title: A survey of mastitis in selected ontario dairy herds.
abstract: A mastitis survey involving 74 Ontario dairy herds was conducted. The prevalence of infection at the quarter level was found to be 4.1% with Streptococcus agalactiae, 4.5% with other streptococcal species and 8.0% with Staphylococcus aureus. Regardless of the infection status, the geometric mean somatic cell count was found to increase with age of the cow but no increase was observed with increasing stage of lactation. The percentage of cows from which a bacterial pathogen was isolated increased with age but not with stage of lactation.
authors.forename: B W
authors.initials: BW
authors.lastname: Brooks
authors.forename: D A
authors.initials: DA
authors.lastname: Barnum
authors.forename: A H
authors.initials: AH
authors.lastname: Meek