Mastitis (inflammation of the mammary glands)

Mastitis (sore breasts) can be a very unpleasant condition. Although not usually life-threatening, mastitis can be very distressing for your pet. It is important to seek veterinary advice as soon as possible because the use of antibiotics, whenever indicated by your veterinarian, can be very helpful in resolving the condition. Mastitis can worsen quickly and have serious consequences if not promptly addressed.

©Glen Cousquer

Mastitis means that the mammary tissue (breast tissue) is inflamed. Usually only one or two teats are affected. The most common cause is a bacterial infection that generally occurs in bitches after they have given birth and while they are feeding puppies. A non-infectious mastitis may also develop when the puppies are weaned suddenly and the mammary glands become warm, swollen and hot because the milk is not being drained by feeding puppies.

In most cases the first sign you will notice is that bitch is unwilling to feed her puppies. She may snap at them when they approach. The puppies may be more restless than normal and crying because they are hungry. Your bitch may have swollen and red or discolored mammary tissue which will feel hot (or in rare cases – cold) and painful to the touch. If you gently squeeze on the nipples a small amount of clotted milk or even blood or pus may be expelled. Bitches with mastitis are often unwell, off their food and have a fever. In very severe cases the mammary gland may develop ulcers which ooze pus or wounds that scab over.

As disease progresses the infection may enter your bitch’s bloodstream, and this can cause signs of sepsis with vomiting and depression.

Your veterinarian will probably suspect that your dog has mastitis based on your description of the symptoms and the fact that they are nursing puppies. Your veterinarian will want to examine your dog and may perform an ultrasound examination of the mammary tissue; milk secretions may be collected aseptically at that time.

Tests on a milk sample will show if there is a bacterial infection. If so, a sample may be sent to a laboratory to see if bacteria can be grown so that tests can be done to find the right antibiotics to clear up the infection. If your pet has signs of general illness, such as fever or poor appetite, other tests, including blood tests, are likely to be carried out.

All breeds of dog, any age and size and new or experienced mothers are all at risk of mastitis. Mastitis usually develops from a bacterial infection that enters the breast tissue through the nipple. The risk of mastitis is higher in bitches feeding in areas with poor hygiene or if there is a lot of trauma to the nipples. For this reason, it is important to keep the whelping box area clean and to remove any soiled bedding as soon as possible. After whelping, bitches should be closely monitored to document whether puppies are nursing in all glands. Glands that are being “neglected” may engorge with stagnated milk, predisposing them to mastitis. If that happens, assist the feeding of puppies to direct them to suckle on engorged glands.

Puppies that are very aggressive in feeding and constantly nurse, may cause the teat orifices to be constantly open, thus allowing for the entry of bacteria. If feasible, puppies, after feeding, can be kept away from the dam for a couple of hours to allow the glands to rest properly.

Rarely, the infection is spread through the blood and settles out in the mammary tissue. Mastitis can also develop in bitches where milk has accumulated in mammary glands for a long period time due to puppies not feeding effectively, especially after sudden weaning or the death of puppies.

If your dog has bacterial mastitis your vet may give you a course of antibiotics. In most cases the problem should start to clear up within a few days of starting the treatment. It is very important that you continue to give the treatment until the course is finished, even if your dog seems completely better. If you stop treatment too early the problem may come straight back, and the tablets may not work a second time.

In some very severe cases abscesses develop in the mammary tissue or the tissue starts to die, and gangrene may develop. This is a potentially life-threatening condition, and your pet will need to be admitted to hospital for intensive care and possibly surgical treatment to remove parts of the damaged mammary tissue may be required.

Your veterinarian may discuss with you whether milk suppression is required and can give medication to do this if required. This will depend on the reason for mastitis development and the stage of development of the puppies.

Your veterinarian will be able to prescribe some drugs that help to reduce the pain. The mammary tissue can be alternately packed with hot and cold dressings to reduce discomfort and inflammation and these dressings can be kept in place by putting a tee-shirt on your bitch.

Initially the puppies should be removed from the bitch and given supplementary milk feeding. Your veterinarian may recommend that you hand milk the affected glands every 6 hours. This keeps blood flowing to the gland to aid healing. However, it is useful to allow the puppies to suckle again quite soon to keep the mammary glands emptied. Choice of antibiotic is important as most antibiotics will cross into the milk so, if puppies are to nurse, only antibiotics safe for use in puppies can be given. If the bitch is receiving antibiotics puppies must be monitored closely for signs of diarrhea or other illness and may need to be removed from the bitch if they are having problems.

Most dogs recover very quickly from simple mastitis, usually starting to get better within a few days, provided treatment is started quickly. However, more severe cases where emergency care is required, can be fatal and if bitches do survive, the recovery from illness and surgery may be more prolonged over many weeks.