Prepartum teat apex colonization with Staphylococcus chromogenes in dairy heifers is associated with low somatic cell count in early lactation S. De Vliegher a,* , H. Laevens a , L.A. Devriese b , G. Opsomer a , J.L.M. Leroy a , H.W. Barkema c , A. de Kruif a a Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium b Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium c Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI, Canada C1A 4P3 Received 30 May 2002; received in revised form 23 September 2002; accepted 22 October 2002 Abstract A high number of dairy heifers freshen with udder health problems. The prevalence of teat apex colonization (TAC) with Staphylococcus chromogenes, one of the most widespread coagulase- negativestaphylococci(CNS)inmilksamplesfromfreshlycalveddairyheifers,wasmeasuredcross- sectionallyinnon-lactatingheifersoneightcommercialdairyfarmsinBelgium.Thein¯uenceofage on this prevalence, and the association between teat apex colonization with S. chromogenes prepartum and quarter milk somatic cell count (SCC) in early lactation were studied. In total, 492 teat apices were sampled from 123 heifers. The age of the heifers varied from 8 to 34 months. Overall, 20% of the heifers had at least one teat apex colonized with S. chromogenes. Of all teats sampled, 10% were colonized with S. chromogenes. The chance of having at least one teat apex colonizedwith S. chromogenes increasedwithageoftheheifer.Thepresenceofprepartumteatapex colonization with S. chromogenes was not associated with intramammary infection (IMI) early postpartum with the same bacterium. On the contrary, teat apex colonization with S. chromogenes prepartum appeared to protect quarters in the ®rst few days of lactation from having somatic cell count 200,000 cells/ml milk, commonly accepted as the threshold for intramammary infection. # 2002 Elsevier Science B.V. All rights reserved. Keywords: Cattle±bacteria; Intramammary infection; Mastitis; Somatic cell count; Staphylococcus chromo- genes; Teat apex colonization Veterinary Microbiology 92 (2003) 245±252 * Corresponding author. Tel.: 32-9-264-75-45; fax: 32-9-264-75-34. E-mail address: sarne.devliegher@rug.ac.be (S. De Vliegher). 0378-1135/02/$ ± see front matter # 2002 Elsevier Science B.V. All rights reserved. PII:S0378-1135(02)00363-2