title: Teat apex colonization with coagulase-negative Staphylococcus species before parturition: Distribution and species-specific risk factors.
abstract: Coagulase-negative staphylococci (CNS) are the main cause of bovine intramammary infections and are also abundantly present in extramammary habitats such as teat apices. Teat apex colonization (TAC) with CNS has already been explored in lactating dairy cows at the species level, whereas this is not true for dry cows and end-term heifers. Therefore, the aim of this observational study was to describe CNS TAC in nonlactating dairy cows and end-term heifers in Flemish dairy herds and to identify associated risk factors at the herd, cow, and quarter level. All CNS were molecularly identified to the species level using transfer RNA intergenic spacer PCR (tDNA-PCR) and sequencing of the 16S rRNA gene, allowing for species-specific statistical analyses using multivariable, multilevel logistic regression. Staphylococcus devriesei, Staphylococcus chromogenes, Staphylococcus haemolyticus, and Staphylococcus equorum were the most frequently isolated species. Staphylococcus chromogenes was the sole species colonizing teat apices of cows and heifers in all herds, whereas large between-herd differences were observed for the other species. Teat apices of red and white Holstein Friesians, of quarters dried off without an internal teat sealer, and swabbed in months with lower precipitation and higher ambient temperature were significantly more likely to be colonized by S. devriesei. Slightly dirty teat apices and teat apices swabbed in months with lower precipitation had higher odds of being colonized by S. chromogenes, whereas teat apices sampled in months with lower precipitation and higher ambient temperature were more likely to be colonized by S. haemolyticus. Dirty teat apices and teat apices swabbed in months with lower ambient temperature in combination with low precipitation had higher odds of being colonized by S. equorum. Diverse factors explaining CNS TAC, yet mostly related to humidity, ambient temperature, and hygiene, substantiate differences in epidemiological behavior and ecology between species.
authors.affiliation: M-team and Mastitis and Milk Quality Research Unit, Department of Reproduction, Obstetrics, and Herd Health, Ghent University, 9820 Merelbeke, Belgium. Electronic address: Anneleen.Devisscher@UGent.be.
authors.forename: A
authors.initials: A
authors.lastname: De Visscher
authors.affiliation: M-team and Mastitis and Milk Quality Research Unit, Department of Reproduction, Obstetrics, and Herd Health, Ghent University, 9820 Merelbeke, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Piepers
authors.affiliation: Department of Pathology, Bacteriology, and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Haesebrouck
authors.affiliation: M-team and Mastitis and Milk Quality Research Unit, Department of Reproduction, Obstetrics, and Herd Health, Ghent University, 9820 Merelbeke, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: De Vliegher
mesh_terms: D000818:Animals; D002417:Cattle; D003030:Coagulase / Q000235:genetics*; D005260:Female; D007774:Lactation; D016015:Logistic Models; D008414:Mastitis, Bovine / Q000382:microbiology*; D036801:Parturition; D011247:Pregnancy; D012307:Risk Factors; D013045:Species Specificity; D013203:Staphylococcal Infections / Q000662:veterinary*; D013210:Staphylococcus / Q000145:classification / Q000502:physiology*
chemical_list: D003030:Coagulase
keywords: coagulase-negative Staphylococcus species; teat apex