Contributors: Andrew Gardiner, Joseph Harari, Carlos Pinto

 Species: Feline   |   Classification: Diseases

Introduction Pathogenesis Diagnosis Treatment Outcomes Further Reading


  • Cause: usually ascending bacterial (Staphyloccus aureus, Escherichia coli, etc) infection through nipple during nursing (may be hematogenous or lymphogenous) - predisposed or exacerbated by trauma, unsanitary conditions. 
  • Signs: one or more mammary glands that are hot, eliciting signs of pain at touch or when trying to nurse, with purulent or blood-tinged mammary secretions; pyrexia, anorexia; kittens may be unable to feed - restless, cry, appear bloated or fail to thrive. At early stages of infection, it may be subclinical with only galactostasis of affected glands. 
  • Diagnosis: clinical signs; milk cytology showing degenerate neutrophils and bacteria; complete blood count may reveal neutrophilic leukocytosis with left shift. 
  • Treatment: systemic antibiotics, application of cold compresses to affected mammary glands; may need to wean kittens or feed artificially until infection controlled. 
  • Prognosis: good with prompt treatment.
Print off the owner factsheet Mastitis (inflammation of the mammary glands) to give to your client.

Presenting Signs

  • Lactating queen. 
  • Hot, mammary glands painful to touch. 
  • Purulent mammary secretions. 
  • Kittens unable to feed - restless, crying and may appear bloated



Predisposing Factors


  • Queen and kittens under unsanitary conditions in nursing box. 
  • Ascending bacterial infection predisposed by: 
    • Constant nursing in queens with large litters.  
    • Secondary galactostasis in queens nursing small litters.


  • Ascending bacterial infection through nipple during nursing.
  • May be hematogenous or lymphogenous spread, eg metritis Acute metritis.


Presenting Problems

  • Young restless, not feeding, crying.
  • Swollen mammary glands.
  • Pyrexia Pyrexia: overview.

Client History

  • Nursing female.

Clinical Signs

  • Hot mammary glands painful to touch.
  • Purulent mammary secretions.
  • Kittens unable to feed - restless, cry, appear bloated.
  • Pyrexia.
  • Anorexia.

Diagnostic Investigation



  • Milk sample - culture and sensitivity Bacteriology.
  • Escherichia coliStaphylococcus spp or Streptococcus spp most commonly present.


  • Examination of milk sample shows neutrophils (with intracellular bacteria)/red blood cells.

Definitive diagnostic features

  • History and clinical signs.
  • Bacteriological culture and sensitivity results.

Differential Diagnosis


Initial Symptomatic Treatment

  • Start antibiotic therapy Therapeutics: antimicrobial drug with drugs considered safe for queen and kittens; eg broad spectrum beta-lactam antibiotics, eg amoxicillin Amoxicillin/clavulanic acid Clavulanate or cephalexin Cefalexin.  
  • Modify antibiotic therapy based on culture results and evaluation of milk pH. 
  • Remove kittens until therapy instigated. 
  • Suppress lactation by administration of cabergoline Cabergoline
  • Wean, feed artificially Milk replacers - this is controversial, some authors recommend nursing to empty gland. 
  • Most milk secretions from mastitis are alkaline, which favor the distribution of weakly acidic drugs such as ampicillin Ampicillin or cephalosporins. 
  • Distribution of weakly alkaline drugs such as trimethoprim sulfa  Trimethoprim, erythromycin Erythromycin may be compromised if the pH is > 7.4

Standard Treatment

  • Remove kittens - may need to wean/feed artificially until infection controlled. 
  • Suppress lactation by administration of cabergoline. 
  • Appropriate antibiotic therapy ideally according to milk culture and sensitivity results. 
  • Cold and hot packing of affected glands. 
  • Surgical drainage Drain: surgical wounds or mastectomy Mastectomy of abscesses/debridement of gangrenous areas as necessary. 
  • Antiseptic infusions into gangrenous or abscessed glands.


  • Septicemic animals require IV fluids, antibiotics.
  • Kittens weaned need good husbandry techniques.


Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Wilson C R (2013) Feline gangrenous mastitis. Can Vet J 54 (3), 292-294 PubMed
  • Dernell W B, Kreeger J (1992) Peracute necrotizing mastitis as a cause of fatal septicemia and endotoxemia in a dog. Canine Pract 17 (6), 25-29 VetMedResource.

Other Sources of Information