Female Dog Lactation
It’s normal for female dogs to start producing milk after giving birth to puppies. Milk production usually begins a few weeks prior to whelping and peaks around 3-5 weeks after the puppies are born. The milk provides the essential nutrients needed for the newborn puppies to grow and thrive. Mother dogs will continue to produce milk as long as the puppies continue nursing.
The puppies are usually completely weaned between 6-10 weeks of age, at which point the mother dog’s milk production starts to naturally decline. However, it’s not unusual for some leakage of milk to continue for up to a month after the puppies have been weaned, especially if the nipples are stimulated. This happens because removing the puppies interrupts the milk production cycle and it takes some time for the dog’s mammary glands to cease production entirely (VCCAHospitals, 2022).
So in summary, it’s perfectly normal for female dogs to produce milk before and after giving birth to feed their puppies. Some continued leakage after weaning may persist for about a month as the dog’s body adjusts.
Pseudopregnancy
Pseudopregnancy, also known as false pregnancy, is a condition that can occur in unspayed female dogs who go through hormonal changes that mimic pregnancy even though the dog has not been bred or is not actually pregnant. This happens because the estrogen levels rise after the dog goes into heat, which causes the dog’s body to behave as if she is pregnant. The dog then enters the diestrus stage of the estrus cycle, where progesterone levels remain elevated for 8-10 weeks. These hormonal changes cause physical symptoms including swelling of the mammary glands, milk production, nesting behaviors, and mothering of toys or other objects.
According to vcahospitals.com, pseudopregnancy typically lasts 2-3 weeks, but in some cases can last 1-2 months or longer. The elevated progesterone levels stimulate the mammary glands to produce milk, even though the dog is not actually nursing puppies. This leads to the dog’s nipples becoming enlarged and the glands swelling with milk production. The milk may spontaneously leak or express from the nipples until the pseudopregnancy ends and the progesterone levels return to normal.
Mammary Gland Tumors
Another cause of abnormal lactation in dogs can be mammary gland tumors, which are especially common in intact or unspayed female dogs. Mammary tumors account for about 42% of all diagnosed tumors in female dogs, with a lifetime risk of 23-34%.
These mammary tumors can be benign or malignant. Benign mammary tumors generally have a better prognosis and are not as likely to spread to other parts of the body. However, some types like complex and mixed mammary tumors have a higher chance of reoccurrence. Malignant mammary tumors, if not caught early, can metastasize and spread to the lymph nodes and lungs which has a much poorer prognosis.
That’s why it’s so important to have any abnormal lactation or lumps on the mammary glands examined by a veterinarian right away. They can run tests like fine needle aspiration or biopsy to determine if a tumor is present and if it is benign or malignant. Early detection and treatment is key for the best outlook with mammary cancer.
Medications
There are some medications that may cause lactation in female dogs who are not pregnant or recently gave birth. These include:
- Metoclopramide – This medication is sometimes prescribed to increase milk production in nursing dogs. However, it may also cause lactation as a side effect in some dogs that are not pregnant or nursing 1.
- Chlorpromazine – This antipsychotic medication has been reported to cause lactation in dogs as a side effect 2.
- Reserpine – This hypertension medication may also stimulate lactation in some dogs 3.
If your dog is lactating but has not been bred recently, be sure to let your veterinarian know about any medications she is taking. Some medications may need to be adjusted or discontinued if they are causing this side effect.
Diagnostic Tests
If a female dog is lactating abnormally, veterinarians will run several diagnostic tests to determine the cause. Analyzing the composition of the milk itself can provide important clues. The milk may be tested for bacterial cultures to diagnose mastitis, an inflammation of the mammary glands typically due to infection. Abnormal milk texture or color may also indicate mastitis. Blood tests are also useful to check hormone levels related to pregnancy and lactation. Elevated progesterone levels may signal a pseudo-pregnancy. Testing estrogen and prolactin can determine if those hormones are abnormally high or low, which could affect milk production.
Veterinarians may also recommend imaging tests like an ultrasound to examine the mammary glands and look for tumors or other abnormalities. A biopsy of the mammary tissue may be taken as well to analyze cells and tissue. According to https://vetster.com/en/conditions/dog/mammary-inflammation-mastitis, ultrasound and biopsy allow veterinarians to evaluate any architectural changes in the mammary glands and differentiate between mastitis, hormonal issues, and mammary tumors as the cause of abnormal lactation.
Treatment
If lactation is occurring due to medications, the medication should be stopped immediately under veterinary supervision. Medications that can cause lactation include antipsychotics, antiepileptics, and hormones used for heat suppression. Stopping the medication will halt milk production within a few days in most cases.
For pseudopregnancy, veterinarians may prescribe anti-hormonal drugs such as cabergoline to suppress prolactin and reduce milk production. According to the Merck Veterinary Manual, the recommended dosage for cabergoline in dogs is 5 mcg/kg given orally every 24 hours for 5-10 days [1]. Other medications may be prescribed as well to relieve anxiety or fluid retention associated with the condition.
If a mammary tumor is present, surgery will likely be necessary. Malignant mammary tumors can be aggressive, so surgical removal provides the best chance for a cure. The extent of surgery depends on the type, size, and location of the tumor.
[1] Pseudopregnancy in Small Animals. Merck Veterinary Manual. https://www.merckvetmanual.com/reproductive-system/reproductive-diseases-of-the-female-small-animal/pseudopregnancy-in-small-animals. Accessed March 5, 2023.
Home Remedies
One way to help dry up a female dog’s milk supply at home is to use cold compresses. Placing a cold compress or ice pack wrapped in a towel on the dog’s mammary glands can provide relief from engorgement and discomfort. It’s important not to massage or stimulate the nipples, as this can actually prolong lactation. The cold temperature helps constrict blood vessels and reduces milk production over time. Do this for 5-10 minutes several times per day. Just be sure not to make it too cold to avoid damaging the skin.
Reducing food and water intake for a day or two may also help slow milk production. But be sure to do this gradually and under veterinary guidance to avoid dehydration or other health issues. Herbal remedies like parsley or sage may help dry up milk as well, but consult your vet first. Avoid handling the dog’s teats to prevent stimulating further milk production. Be patient, as it can take a week or two for the dog’s milk to fully dry up. Contact your vet if you have any concerns or if milk production persists longer than expected.
Prevention
The best way to prevent false pregnancies in female dogs is to have them spayed if they are not intended for breeding. Spaying removes the ovaries and uterus, eliminating the hormonal fluctuations that trigger pseudopregnancy symptoms. Veterinarians typically recommend spaying before the first heat cycle, as early spaying nearly eliminates the risk of mammary tumors. For dogs already exhibiting pseudopregnancy symptoms, spaying may be recommended after the current episode has resolved.
For spayed dogs or those not ready for spaying, medication can help prevent recurrence of pseudopregnancy. Prolactin inhibitors such as bromocriptine or cabergoline are sometimes prescribed to interfere with the hormonal feedback loop. These medications are given for several weeks following ovulation to prevent secretion of milk and development of mothering behaviors. However, potential side effects include vomiting and diarrhea. Natural supplements such as vitamin B6, vitamin E, and evening primrose oil may help stabilize hormones and curb symptoms without adverse effects.
Limiting tactile stimulation of the mammary glands can also help prevent recurrence. Female dogs should not be allowed to nest or mother toys during an episode. Any “adopted” puppies or objects should be removed from the environment until hormones have stabilized.
When to See a Vet
Any lactation in spayed dogs should prompt an investigation by a veterinarian. Even in intact dogs, abnormal milk production can indicate an underlying health issue. It’s important to have a vet examine the dog’s mammary glands and assess her overall health.
Some signs require urgent vet visits, including bloody discharge from the nipples, skin changes around the nipples and mammary glands (e.g. redness, swelling, sores), and presence of lumps or masses in the mammary tissue. These symptoms may indicate inflammation, infection, or mammary tumors, which all require rapid diagnosis and treatment.
According to the VCA Hospitals, malignant mammary tumors are the most common type of tumor in unspayed female dogs. They recommend spaying dogs before their first heat cycle to drastically reduce the risk of mammary cancer (VCA Hospitals). Signs of mammary tumors include single or multiple palpable masses under the abdomen skin. Mammary tumors can metastasize to the lymph nodes and lungs, leading to symptoms like coughing, breathing issues, and leg lameness (NCSU Vet Hospital).
In summary, any abnormal milk production in female dogs should prompt a veterinary visit to diagnose and treat the underlying cause.
Summary
Female dogs can experience abnormal lactation for several reasons, including pseudopregnancy, mammary gland tumors, and medications. Pseudopregnancy, also known as false pregnancy, occurs after a female dog goes through a heat cycle and experiences hormonal changes. These hormonal changes can stimulate milk production and mothering behaviors, even though the dog is not actually pregnant. Mammary gland tumors, while not common, can also result in abnormal lactation. Certain medications like estrogen can also trigger lactation.
It’s important to have a veterinarian examine a female dog experiencing abnormal milk discharge, as the cause needs to be properly diagnosed. Tests like bloodwork, imaging, and mammary gland biopsies may be required. Appropriate treatment will depend on the underlying cause, and can include medications, surgically removing tumors, and spaying dogs prone to pseudopregnancy. Consulting a vet right away provides the best chance for proper diagnosis and treatment of abnormal lactation in female dogs.
