Trueperella pyogenes mastitis in Cows (Bovis) | Vetlexicon
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Trueperella pyogenes mastitis

ISSN 2398-2993

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Synonym(s): T pyogenes


  • Cause: Trueperella pyogenes (often mixed infection with other pathogens including Streptococcus dysgalactiae, Peptococcus indolicus and Fusobacterium necrophorum.
  • Signs: mastitis affecting dry cows and heifers, seen mostly during warmer months.
  • Diagnosis: clinical signs.
  • Treatment: frequent stripping, systemic antibiotics and NSAIDs.
  • Prognosis: full recovery of infected quarter is rare. Treatment is aimed at saving the animal.

Presenting signs

  • An animal standing apart from the others, often lame, dull and anorexic.
  • Pyrexia.
  • Swollen teats with often large numbers of flies feeding around them.
  • Foul-smelling, thick, yellow secretions from the infected quarter, often tinged with blood.

Acute presentation

  • Swollen udder , pyrexia, altered gait due to pain in the udder.

Geographic incidence

  • Most common in temperate areas of the northern hemisphere.

Age predisposition

  • All ages can be affected but especially common in maiden heifers prior to calving.

Breed/Species predisposition

  • None.

Public health considerations

  • Mastitis is often the main reason for antibiotic use on dairy farms and better control of mastitis in general is, therefore, crucial if we are to reduce the requirement for antibiotics and reduce the risk of antimicrobial resistance.

Cost considerations

  • Bovine intramammary infections caused by T. pyogenes are associated with the highest somatic cell count in milk and significant losses in milk yield as well as high percentages of nonfunctional quarters.



Predisposing factors


  • Trauma and irritation of the udder, which may cause leaking and disruption of the keratin seal normally present in the teats of non-lactating cattle.


  • Presence of the sheep head fly, Hydrotaea irritans, which is a commonly observed nuisance parasite around livestock in the summer months. Flies


  • The virulence of T. pyogenes is attributed to several mechanisms including pyolisin (a potent cytolisin related to tissue damage), neuraminidases (nanH and nanP genes), fimbriae (fimA), and collagen-binding protein (cbpA) which are associated with mucosal adherence and colonization.
  • Development of pyogranulomatous reactions in tissues and organs is another pathogenic mechanism of T. pyogenes.
  • Due to opportunistic behavior of the micro-organism, several routes of transmission are possible.


  • Major means of transmission is thought to be Hydrotoea irritans (sheep head fly).
  • These flies live in sheltered areas such as woods and copses and only fly out when wind-speeds are low.
  • Larvae overwinter in light, sandy soils, and emerge as adults in July, August and September which is when most cases of summer mastitis are seen.


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Further Reading


Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Zastempowska E & Lassa H (2012) Genotypic characterization and evaluation of an antibiotic resistance of Trueperella pyogenes (Arcanobacterium pyogenes) isolated from milk of dairy cows with clinical mastitis. Vet Mic 161, 153-158 PubMed.
  • Malinowski E, Lassa H, Klossowska A, Markiewicz H, Kaczmarowski M & Smulski (2006) Relationship between mastitis agents and somatic cell count in foremilk samples. Bull vet inst pulawy 50, 349–352 PubMed.
  • Jost B H & Billington S J (2005) Arcanobacterium pyogenes: molecular pathogenesis of an animal opportunist. Anton van leeuw 88, 87–102 PubMed.
  • Grohn Y T, Wilson D J, Gonzalez R N, Hertl J A, Schulte H, Bennett G & Schukken Y H (2004) Effect of pathogen-specific clinical mastitis on milk yield in dairy cows. J dairy sci 87, 3358–3374 PubMed.
  • Waage S, Skei H R, Rise J, Rogdo T, Sviland S & Ødegaard S A (2000) Outcome of clinical mastitis in dairy heifers assessed by re-examination of cases one month after treatment. J Dairy Sci 83, 70–76.
  • Yüksel H. T., Özavcı V., Kırkan Ş. (2022) Molecular characterization, determination of virulence genes and antimicrobial susceptibility of trueperella pyogenes in bovine clinical mastitis Cattle Practice, 30, (12) pp.1-18. PubMed

Other Sources of Information

  • Blowey R & Edmondson P (2010) Mastitis Control in Dairy Herds. 2nd edn. CAB International, UK.
  • Radostits O M, Gay C C, Hinchcliff K W & Constable P D (2007) Veterinary Medicine: A Textbook of the Diseases of Cattle, Horses, Sheep, Pigs, and Goats. P A Saunders Elsevier, USA. pp 722-724.