title: Pathogen profile of clinical mastitis in Irish milk-recording herds reveals a complex aetiology.
abstract: Effective mastitis control requires knowledge of the predominant pathogen challenges on the farm. In order to quantify this challenge, the aetiological agents associated with clinical mastitis in 30 milk-recording dairy herds in Ireland over a complete lactation were investigated. Standard bacteriology was performed on 630 pretreatment quarter milk samples, of which 56 per cent were culture-positive, 42 per cent culture-negative and 2 per cent contaminated. Two micro-organisms were isolated from almost 5 per cent of the culture-positive samples. The bacteria isolated were Staphylococcus aureus (23 per cent), Streptococcus uberis (17 per cent), Escherichia coli (9 per cent), Streptococcus species (6 per cent), coagulase-negative Staphylococci (4 per cent) and other species (1 per cent). A wide variety of bacterial species were associated with clinical mastitis, with S aureus the most prevalent pathogen overall, followed by S uberis. However, the bacterial challenges varied widely from farm to farm. In comparison with previous reports, in the present study, the contagious pathogens S aureus and Streptococcus agalactiae were less commonly associated with clinical mastitis, whereas, the environmental pathogens S uberis and E coli were found more commonly associated with clinical mastitis. While S aureus remains the pathogen most commonly associated with intramammary infection in these herds, environmental pathogens, such as S uberis and E coli also present a considerable challenge.
authors.affiliation: Animal & Bioscience Research Department, Animal & Grassland Research & Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland. orla.keane@teagasc.ie
authors.forename: O M
authors.initials: OM
authors.lastname: Keane
authors.forename: K E
authors.initials: KE
authors.lastname: Budd
authors.forename: J
authors.initials: J
authors.lastname: Flynn
authors.forename: F
authors.initials: F
authors.lastname: McCoy
mesh_terms: D000818:Animals; D002417:Cattle; D003612:Dairying; D004926:Escherichia coli / Q000302:isolation & purification / Q000472:pathogenicity; D005260:Female; D007494:Ireland; D008414:Mastitis, Bovine / Q000453:epidemiology / Q000382:microbiology*; D008892:Milk / Q000382:microbiology*; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000472:pathogenicity; D013290:Streptococcal Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D013291:Streptococcus / Q000302:isolation & purification / Q000472:pathogenicity