How to treat mastitis in dogs?

Mastitis — inflammation or infection of the mammary gland — is a condition that can quickly turn a routine whelping into a stressful medical emergency for both a mother dog (dam) and her puppies. The guidance below is practical, veterinary-minded, and written for anyone caring for nursing, foster, or rescued bitches so you can recognize trouble early and take the right steps.

Protecting nursing dogs and their puppies from mastitis

When a dam develops mastitis, her milk supply and willingness to let pups nurse can fall apart within hours. I typically see owners who assumed a sleepy litter or a sleepy mother was normal until puppies stop gaining weight; in many of those cases the underlying problem is a painful gland the dam resists using. Prompt recognition and treatment protect the dam’s health, preserve milk production where possible, and reduce the need for costly emergency care or prolonged supplemental feeding of pups.

Scenarios that dog lovers commonly face include a first-time mother whose teats are sore from vigorous suckling, a foster dog brought into a rescue with an active litter, or a rescued whelp where inadequate nursing left teats chapped and vulnerable. The emotional stakes are high: puppies that lose access to healthy milk can dehydrate or fail to thrive quickly, and owners often feel helpless watching a mother in pain. Financially, addressing mastitis early usually means a short course of treatment and faster recovery, whereas delayed care can lead to hospital stays, surgery for abscesses, or even loss of the mammary tissue and permanent reduction in future milk production.

Quick action can prevent complications. If you notice a dam that is reluctant to feed, has a hot gland, or if multiple pups are underperforming at the milk bar, treat the situation as potentially urgent and get professional advice rather than waiting for symptoms to “settle down.”

Immediate steps to take if you suspect mastitis

1. Assess the situation quickly: look at the mother’s behavior and body temperature, inspect teats and milk, and weigh puppies to check for recent weight changes.
2. Call your veterinarian or emergency clinic immediately. Describe specific signs (temperatures, appearance of milk, how many glands are affected, pups’ condition) so you can get clear triage advice.
3. Stabilize while you arrange care: keep the dam warm and quiet, clean soiled bedding, and use gentle warm compresses on affected glands if your vet says it’s okay. Temporarily prevent pups from nursing on a clearly infected gland if advised—covering the gland with a light barrier or using an e‑collar on pups can work short term—but follow your clinic’s instructions before doing this broadly.
4. Avoid giving any antibiotics, anti-inflammatories, or home remedies unless explicitly prescribed. Some human medications are dangerous to dogs and some topical products can contaminate milk or worsen inflammation.

How mastitis develops — infection, blockages and inflammation

Mastitis most often begins with milk stasis: when milk isn’t removed regularly, a teat duct can become clogged and milk accumulates. That stasis creates an environment where bacteria that normally live on the skin or in the mouth may move into the teat and multiply. Bacteria commonly implicated include Staphylococcus and Streptococcus species, and occasionally gram-negative organisms; a veterinarian will often choose antibiotics that target these likely bugs.

The mammary gland responds to obstruction or infection with a local inflammatory reaction. Cells in the gland release chemicals that increase blood flow and cause heat, swelling, pain, and firmness; those same processes can reduce milk flow and change milk appearance. If the infection is severe, it may progress to abscess formation or necrosis of gland tissue, and toxins may enter the bloodstream leading to systemic illness — fever, weakness, and loss of appetite.

Hormonal and lactational physiology also play a role. The early postpartum period is a time of heavy milk production and frequent removal; any interruption (poor latch, trauma, or abrupt decrease in nursing) may predispose a gland to stasis. Certain systemic illnesses or poor nutrition may make a dam less able to resist invading bacteria, so overall health affects risk.

High-risk periods: when mastitis is most likely to occur

The highest-risk window is the first one to four weeks after whelping. That period involves intense, frequent nursing and immature teats that may be raw from vigorous suckling. I commonly see cases that begin in the first week after birth when pups are establishing a latch or later when a few pups dominate access to certain glands and clog others by overfeeding.

Trauma to teats from sharp puppy teeth, poor nursing positions, or large litters where pups have to compete can leave tiny breaks in the skin that allow bacteria in. Abrupt weaning or inconsistent removal of milk — for example, when pups are removed for short periods during human activities or when a dam is stressed and refuses to let them nurse properly — can also increase the chance of milk stasis and infection.

Symptoms that demand attention — spotting mastitis early

• Local changes in the gland: a section of the mammary chain may become swollen, hot to the touch, firm or hard, painful when handled, or darker and redder than surrounding skin. Milk from an affected gland may look discolored, bloody, or have a strange odor.
• Systemic signs in the dam: fever (a rectal temperature over about 103°F / 39.5°C is concerning), shivering, marked lethargy, vomiting, or anorexia. Pale gums, very fast breathing, or collapse are emergency signs that suggest sepsis or severe toxemia.
• Signs in the pups: poor weight gain, weakness, failure to suckle, or visible dehydration (sunken eyes, tacky gums). Multiple pups failing to thrive often points to an issue with milk supply or milk quality.
• Severe complications: a fluctuant area beneath a tense, red gland may indicate an abscess. Skin that changes color, becomes grey or black, or a gland that stops bleeding when pinched lightly may suggest necrosis and needs immediate attention.

Owner action checklist: what to do first and next

First, call your veterinarian with clear, concrete observations: the dam’s rectal temperature, whether the limbs or mammary glands are hot or painful, the number of glands involved, and how the puppies are doing (weights, activity, nursing behavior). A photo or short video of the dam and the litter can be very helpful for triage.

If the vet instructs you to take a rectal temperature, use a digital thermometer and lubricant, and handle the dam gently. Note the reading and report it. If you cannot safely restrain the dog, tell the clinic; do not force an exam that risks injury to you or stress to the dam. If the clinic recommends emergency evaluation, arrange transport promptly—mothers showing a high fever, weakness, or pups in distress should be seen immediately.

While you arrange professional care, you can provide comfort measures that are safe and typically recommended: keep the mother warm but not overheated, place clean, dry bedding under the litter, and apply a warm, moist compress to the affected gland for 10–15 minutes every 2–4 hours if your vet approves. Warmth can help relieve blockage and encourage gentle milk flow. If the vet advises gentle hand expression, use clean hands or disposable gloves, support the gland with one hand, and use the thumb and forefinger to press toward the teat in a slow, measured way—stop if the dam shows pain or if pus is expressed, and immediately inform the vet of any abnormal material.

Only give antibiotics, pain relief, or other medications prescribed by the veterinarian. Some common antibiotics for mammary infections may include agents that cover skin flora, but the choice depends on local patterns and whether the dam is nursing. Your vet may recommend milk discard procedures for treated glands or temporarily preventing pups from nursing from treated teats until milk testing and culture guide therapy.

Adjusting the whelping area and nursing routine to aid recovery

Keep the whelping area clean and dry. Replace soiled bedding promptly and monitor the dam’s mammary chain daily. If a particular gland is painful, rotate pups so they nurse more from unaffected glands; this reduces overuse of healthy tissue and helps clear engorged areas. I often advise owners to position pups deliberately and to watch for small pups being pushed away by more vigorous littermates.

Temporarily restricting access to severely affected glands is sometimes indicated but should be done under veterinary guidance to avoid complete milk retention or new sites of stasis. Simple measures like soft, breathable bandages or brief use of nipple covers can prevent pups from nursing a single bad gland while allowing access to others, but these are short-term fixes and require close observation.

Nutrition and hydration are key. A nursing dam needs increased calories and easy access to clean water. If she is off food, encourage palatable, high-quality diets (puppy food or a commercial diet formulated for lactation) and consider small, frequent meals. If the dam will need to be separated from pups for medical reasons, discuss with your vet how to maintain milk production safely or how to transition pups to bottle or tube feeding until the mother recovers.

Essential supplies and tools to manage mastitis at home

Create a small kit you can use immediately: a digital rectal thermometer; clean towels and absorbent bedding; warm packs or microwavable heat wraps (used according to package instructions and never placed directly on skin); disposable gloves and gentle antiseptic wipes (chlorhexidine-based solutions are commonly recommended for skin); a small kitchen scale to weigh puppies daily; and a baby or pet feeding bottle and appropriate puppy milk replacer if supplemental feeding becomes necessary. A syringe or small milk-collection device may be useful only if your veterinarian instructs you how to use it safely for milk sampling or supplemental feeding. Keep phone numbers for your primary vet and the nearest emergency clinic in the kit.

If the condition worsens: complications, escalation and next steps

If a dam’s fever persists after 24–48 hours of treatment, if a gland becomes fluctuant or discolored, if more glands become involved, or if puppies continue to fail to gain weight despite supplemental feeding, return to or contact your veterinarian immediately. Abscesses may need drainage or surgery; necrotic tissue occasionally requires debridement. If systemic signs like collapse, severe vomiting, or difficulty breathing appear, transport the dog to an emergency clinic without delay—these signs may indicate that infection has entered the bloodstream and that intensive care is needed.

For puppies, persistent poor weight gain or dehydration despite supplementing feeds often means more intensive support is needed: a hospitalization with intravenous fluids, warmed feedings, or tube feeding may be lifesaving. Keep track of puppy weights daily and share that information with your vet so they can judge progress objectively.

Sources, veterinary guidance and further reading

• Merck Veterinary Manual: Mastitis and Other Mammary Gland Disorders in Dogs — https://www.merckvetmanual.com/
• American Veterinary Medical Association (AVMA): Lactation and Mammary Health in Dogs — https://www.avma.org/
• World Small Animal Veterinary Association (WSAVA): Guidelines for Clinical Management of Neonates and Nursing Bitches — https://www.wsava.org/
• Ettinger SJ, Feldman EC. Textbook of Veterinary Internal Medicine: Diseases of the Mammary Gland — 8th ed., Elsevier.