Mastitis in Dogs

Mastitis refers to a bacterial infection in the milk ducts of female dogs. Mama dogs have a lot to contend with, including carrying their puppies 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 puppy teeth create a potential playground for bacteria. In most situations, the nursing dog’s immune system can fight off the bacteria, but if mama dog lacks proper nutrition, is overly stressed, or contending with other factors, her immune system can’t successfully clear the bacteria and an infection develops.

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 dog can become seriously ill. Mastitis causes the mammary gland to become blocked, so 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 mom to nurse her puppies because of the pain, so the whole pack suffers.

If you suspect your mama dog has mastitis, contact your veterinarian immediately. They will perform a thorough history and recommend a treatment that is right for both mom and her pups.

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 
  • A complete blood count (CBC) to evaluate blood-related conditions

In situations where your veterinarian suspects the mastitis has spread, they may recommend additional tests to evaluate the overall health of your furry friend. These may include:

  • Chemistry tests to evaluate kidney, liver, and pancreatic function, as well as sugar levels
  • Electrolyte tests to ensure your pet isn’t dehydrated or suffering from an electrolyte imbalance
  • Urine tests to screen for urinary tract infection and other disease, and to evaluate the ability of the kidneys to concentrate urine

Treatment will depend on the severity of the mastitis and the needs of mom and her pups. 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 puppies is important during this time, especially if the puppies 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 dog is pregnant or nursing puppies.

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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