Causes of Canine Mastitis

Canine mastitis is a bacterial infection of one or more of your pup's mammary glands, located in her breasts. This type of infection usually occurs when your dog is nursing her puppies, and it has several causes. If you notice your pup has a fever, is lethargic or avoids nursing her pups, she may be suffering from mastitis and needs immediate veterinary care to prevent the infection from spreading.


Canine Mastitis

When bacteria, including Escherichia coli, Staphylococcus and Streptococcus species, invade the mammary glands of your pooch, they become infected, according to a study published in the February 2011 issue of the "Brazilian Journal of Veterinary Pathology." These infections occur at the end of a pup's pregnancy, just after birth or during pseudopregnancy. Pseudopregnancy, also known as false pregnancy, usually takes place four to nine weeks after your pooch goes into estrus, according to the VCA Animal Hospitals website. Canine mastitis causes your pup a lot of pain, redness and inflammation of the affected teats. The infection can spread throughout the body, eventually becoming fatal without treatment.


Pregnancy and giving birth can be very stressful for a mama dog, compromising her immune system and opening her up to infection, according to the Pet Health Network. Sharp puppy teeth and scratches from the little ones' claws can injure the teats, allowing bacteria into the milk glands, resulting in mastitis, warns PetMD. In addition, parasites, systemic illnesses and poor nutrition can all compromise your pooch's immune system and allow bacteria to flourish, leading to infections in her mammary glands, according to the U.S. Kerry Blue Terrier Club. Another common cause of canine mastitis is keeping your pooch in unsanitary conditions. Even weaning her puppies too early can cause mastitis.

Veterinary Treatment

If you notice your dog's breasts feel hot and swollen to the touch and your pooch seems lethargic, has a lack of appetite or refuses to nurse her puppies, she may suffer from canine mastitis. Get her to the vet right away for treatment. Your vet will examine her teats, take samples of her milk to examine under a microscope and perform blood tests looking for signs of infection, according to PetMD. He will likely prescribe oral antibiotics to give your pup that will eliminate the bacteria from her body and help cure the infection in her teats. Your vet may also recommend warm compresses to help the mammary glands open up and drain, according to the
Merck Veterinary Manual.

Prevention and Considerations

Prevent issues with canine mastitis by giving your pup proper nutrition with foods labeled for growth and reproduction and keep her on a flea-preventative safe for pregnant or nursing canines. Clip the nails of her puppies so they won't scratch their mother's body or teats. Keep your home and her nest area clean, and wash her bedding daily. If your pup is diagnosed and treated for canine mastitis, she may not be able to nurse her puppies, so you'll have to bottle feed them while she's recovering, depending on the recommendations of your vet. In cases where a dog's mammary gland becomes abscessed, it may require surgical removal, depending on the severity.

By Susan Paretts

About the Author
Based in Las Vegas, Susan Paretts has been writing since 1998. She writes about many subjects including pets, crafts, television, shopping and going green. Her articles, short stories and reviews have appeared in "The Southern California Anthology" and on Epinions. Paretts holds a Master of Professional Writing from the University of Southern California.