Mastitis is an inflammation of the mammary glands, usually with bacterial infection. It results from incomplete emptying of the milk glands. The mammary glands become swollen, tender and hot, and may develop dark-red or purple soft spots. The milk may be blood-tinged or off-color.

Systemic signs include fever, restlessness, reduced appetite and discomfort of the mammary glands. The mother will often neglect the young. Pups weaken if not bottle fed. Mother’s infected milk can be harmful. Pups should be weaned immediately and antibiotic therapy initiated. Occasionally mastectomy is required to surgically remove a necrotic mammary gland.

Many pet owners have the mother “spayed” to prevent further complications of nursing pups.