What’s a milk dog?

Have you ever heard of the expression “milk dog”? But what does it mean? To answer this question, let’s talk about dog reproduction and what justifies a female dog to show aggressive behavior after parturition.

What’s a milk dog?

Milk dog is an urban term used to describe females with aggressive behavior after parturition. Usually this behavior is related to the defense of the nest and the puppies. So these dogs can be aggressive with anyone who approaches the puppies because they are perceived as threats to the female dog.

A dog can also have milk on the teats when they undergo hormonal variation in diestrus, so these animals, even without puppies, can defend the nest and some objects. In addition, these dogs may have milk in their breasts. Stimulating milk production without having puppies to breastfeed can favor infection of the mammary gland. This is happening with wounds and even necrosis in the breast region.

Female dogs estrous cycle

Below will be described each stage of the cycle of the female dogs.

The estrous cycle in female dogs is divided into 4 phases:

  • Proestrus;
  • Estrus;
  • Diestrus;
  • Anestrus.


In proestrus, the female canine body is preparing for ovulation and pregnancy. In this phase, hormones make the females have vulvar swelling, bleeding and become more attractive to males. However, at this stage the female still does not accept the male’s copulation.

It is the phase of the “dating” of the dogs, it involves games of attraction between the dogs. Female dogs can be more agitated during this period and even run away. It is important to beware of unwanted leaks.


Estrus, also known as heat, is the period in which the female accepts the male dog’s copulation. It is at this stage that ovulation of the female dog takes place. So only copulations in this period will make the female dogs get pregnant. Estrus can be shorter in some animals as well as longer in others, ranging from 7 to 21 days on average.

In female dogs, the vulva remains swollen, but the bleeding may stop. Care must be taken, as many owners think that the heat is over because the dog has stopped bleeding. But many times, she is just going through her most fertile period.


The diestrus is the phase in which the uterus prepares to receive the embryos, it lasts from 58 to 68 days. Female dogs reduce vulvar edema, and may present translucent secretion in the vulvar region. It is at this stage that many bacteria can develop in the uterus of female dogs resulting in pyometra. And when female dogs reproduce in estrus, diestrus becomes the fetal developmental stage of pregnancy.


Anestrus is the longest phase, lasting up to 4 months in some animals. In this phase, hormonal quiescence occurs in female dogs. Normally at this stage, female dogs do not accept the mount, much less the male’s copulation, and thus can be quite aggressive. The vulva returns to its normal size which makes copulation even more difficult.

Is there any treatment to reduce postpartum aggression in female dogs?

There is not much to be done, except respecting the space is the initial postpartum moment of female dogs. As the days go by, the animals tend to be more comfortable and calmer with the tutor.

As for Pseudo gestation animals, contact with toys that these dogs adopt as puppies should be avoided. The nest built by the dog must be dismantled. And to prevent milk production and avoid mastitis some medicines can be used. Before making any medication for dogs a veterinarian should be consulted.

What can the mother dog’s aggression mean?

The postpartum female dog goes through a series of hormonal variations which can interfere with the mood of some female dog, which makes the animal become aggressive.

Female dogs should be left in quiet environments and you should avoid picking up or having any kind of contact with puppies. If you observe any type of aggression between the dogs and the puppies, a veterinarian should be consulted.

Some breeds are already described as the most frequent for having a good maternal ability. These breeds are:

  • Golden Retriever;
  • Labrador Retriever;
  • Pomeranian;
  • Cocker Spaniel.

Some breeds that usually present difficulties in parturition, need to be taken to the veterinary clinic where the parturient female dog undergoes anesthesia and cesarean section.

Anesthesia can influence the hormonal variation suffered by female dogs at the end of gestation, so they do not create affective bonds with their puppies, becoming aggressive.

Another important point is that the cesarean section must be performed at the appropriate time. If this does not happen, the puppies can be born prematurely and the female dogs do not go through the great hormonal variation at the end of pregnancy, making them not want to be close to their puppies, not produce milk, and often the animal can become aggressive.


“Milk Dogs” are female dogs that can demonstrate protective behavior towards their nest and puppies. This behavior is natural and is a way for the female dog to demonstrate her maternal protective ability. For dogs that have just given birth, just wait the time to see if the animal calms down. For female dogs with pseudo gestation, a veterinarian should be consulted.

Frequently Asked Questions (FAQs): What’s a milk dog?


What to do when the mother rejects the puppy?

First, separate the puppy from the mother. Put it in a warm place, it is also possible to try manually placing the puppy on the mother’s teats for breastfeeding. If this is not possible, consult a veterinarian.

Why does the female dog carry her puppies?

It is normal for a mother female to carry her puppies in her mouth; this behavior is not aggressive. A mother may move her young if she feels threatened. She may bite the puppies’ cubs as a tactic to teach them subordination.

How do female dogs take care of their puppies?

In dogs, females dedicate themselves to their puppies when they are newborns, suckling them and licking their belly, triggering the urination and defecation reflex in them. The female cleans her puppies and spends more time nestling with them, thus maintaining the temperature.


de Souza Teixeira, E. (2001). Princípios básicos para a criação de cães. NBL Editora.

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