Selective treatment of nonsevere clinical mastitis does not adversely affect cure, somatic cell count, milk yield, recurrence, or culling: A systematic review and meta-analysis

Ellen de Jong, Lien Creytens, Sarne De Vliegher, Kayley D. McCubbin, Mya Baptiste, Alexander A. Leung, David Speksnijder, Simon Dufour, John R. Middleton, Pamela L. Ruegg, Theo J.G.M. Lam, David F. Kelton, Scott McDougall, Sandra M. Godden, Alfonso Lago, Päivi J. Rajala-Schultz, Karin Orsel, Volker Krömker, John P. Kastelic, Herman W. Barkema

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Treatment of clinical mastitis (CM) contributes to antimicrobial use on dairy farms. Selective treatment of CM based on bacterial diagnosis can reduce antimicrobial use, as not all cases of CM will benefit from antimicrobial treatment, e.g., mild and moderate gram-negative infections. However, impacts of selective CM treatment on udder health and culling are not fully understood. A systematic search identified 13 studies that compared selective versus blanket CM treatment protocols. Reported outcomes were synthesized with random-effects models and presented as risk ratios or mean differences. Selective CM treatment protocol was not inferior to blanket CM treatment protocol for the outcome bacteriological cure. Noninferiority margins could not be established for the outcomes clinical cure, new intramammary infection, somatic cell count, milk yield, recurrence, or culling. However, no differences were detected between selective and blanket CM treatment protocols using traditional analyses, apart from a not clinically relevant increase in interval from treatment to clinical cure (0.4 d) in the selective group and higher proportion of clinical cure at 14 d in the selective group. The latter occurred in studies co-administering nonsteroidal anti-inflammatories only in the selective group. Bias could not be ruled out in most studies due to suboptimal randomization, although this would likely only affect subjective outcomes such as clinical cure. Hence, findings were supported by a high or moderate certainty of evidence for all outcome measures except clinical cure. In conclusion, this review supported the assertion that a selective CM treatment protocol can be adopted without adversely influencing bacteriological and clinical cure, somatic cell count, milk yield, and incidence of recurrence or culling.

Original languageEnglish (US)
Pages (from-to)1267-1286
Number of pages20
JournalJournal of Dairy Science
Issue number2
StatePublished - Feb 2023

Bibliographical note

Funding Information:
This study was funded by the Canada's Natural Sciences and Engineering Research Council (NSERC) Industrial Research Chair Program granted to H. W. Barkema, with industry contributions from Alberta Milk (Edmonton, AB, Canada), Dairy Farmers of Canada (Ottawa, ON, Canada), Dairy Farmers of Manitoba (Winnipeg, MB, Canada), British Columbia Dairy Association (Burnaby, BC, Canada), WestGen Endowment Fund (Abbotsford, BC, Canada), Lactanet (Guelph, ON, Canada), SaskMilk (Regina, SK, Canada), and MSD Animal Health (Boxmeer, the Netherlands). Ellen de Jong was supported by the NSERC CREATE in Milk Quality Program Scholarship (Saint-Hyacinthe, QC, Canada). Lien Creytens was supported by Flanders Innovation and Entrepreneurship (VLAIO, Brussels, Belgium), grant number HBC.2020.3192. Data collection forms, analytic code, and any other material used in the review are available from the corresponding author upon reasonable request. The authors have not stated any conflicts of interest.

Publisher Copyright:
© 2023 American Dairy Science Association


  • antimicrobial stewardship
  • bacteriological cure
  • clinical mastitis
  • noninferiority
  • rapid diagnostic test

PubMed: MeSH publication types

  • Meta-Analysis
  • Systematic Review
  • Journal Article


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