Mastitis in Cats

A painful bacterial infection in the milk ducts of mother cats


Mastitis refers to a bacterial infection in the milk ducts of female cats. Mama cats have a lot to contend with, including carrying their kittens to term and nursing them, once born. During this time, their breast glands are stimulated to produce milk. The combination of the stress of pregnancy, nursing, and sharp kitten teeth create a potential playground for bacteria. In most situations, the nursing cat’s immune system can fight off the bacteria, but if mama cat lacks proper nutrition, is overly stressed, or is contending with other factors, her immune system can’t successfully clear the bacteria and an infection develops. Mastitis is most common in older cats.

Although it is usually limited to one or two teats, mastitis is extremely painful and, if left untreated, the bacteria can spread and the mama cat can become seriously ill. Mastitis causes the mammary gland to become blocked, thus milk cannot be released. The teat swells and becomes red and painful to the touch. Sometimes pus or discolored milk may be released. It becomes increasingly difficult for mama cat to nurse her kittens because of the pain, so the whole litter suffers.

If you suspect your mother cat has mastitis, contact your veterinarian immediately. They will perform a thorough history and recommend treatment that is right for both mom and kittens.

Your veterinarian may recommend tests, which could include:

  • Needle aspiration and examination of discharge 
  • Microscopic evaluation of the milk or any discharge
  • Bacterial culture and sensitivity of the fluid, to identify bacteria type 
  • Complete blood count (CBC), chemistry profile, urinalysis, and thyroid function test (T4) to check for underlying disease 
  • Tests for feline leukemia (FeLV) and feline immunondeficiency test (FIV), especially if your cat goes outdoors

Treatment will depend on the severity of the mastitis and the needs of mom and her kittens. Antibiotics are often prescribed to treat the bacterial infection. Applying warm compresses to the infected teats helps them to open and drain. Proper nutrition for both mom and her babies is important during this time, especially if the kittens can’t nurse due to the discomfort mom is experiencing.

Your veterinarian is the key source of information about the health and well-being of your best friend, so contact them for more information or advice—especially if your cat is pregnant or nursing kittens.

If you have any questions or concerns, you should always visit or call your veterinarian – they are your best resource to ensure the health and well-being of your pets.


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