The stages of pregnancy in dogs are important to understand for the dog breeder as he or she will need to learn what happens during this delicate time and what to expect as a dog's pregnancy progresses. The wise dog breeder, breeding for the first time, will want to become accustomed with these stages as much as possible. Knowledge is ultimately power when it comes to breeding dogs regardless of whether it's done for business or simply as a much loved hobby. Following is information about the several stages of pregnancy in dogs from veterinarian Dr. Ivana Crnec.
An Insight into Pregnancy in Dogs
The arguments for breeding are self-evident. First, and most important to our hearts, we perpetuate our dogs. The dog’s relatively short lifespan, of just over 12 years on average, is the cause of the greatest sadness we have as dog owners. With purebreds in particular, breeding creates a continuity, almost an immortality.
Second, breeding is natural – a dog should have the right to breed. We transpose our ethical values onto our dogs. Letting your dog have pups is a beautiful ideal.
The dog’s reproductive cycle is relatively complex and consists of four different stages (proestrus, estrus, diestrus and anestrus). There are differences depending on whether the cycle was completed with or without a mating. If there was a mating during the cycle, pregnancy is the goal.
Most pregnancies in dogs last for 62 to 65 days, but there are considerable variations. Larger litters often have shorter gestations, with whelping occurring as early as 57 days, while smaller litters may not be delivered until 67-68 days or even as late as 72 days after fertilization.
The factors that influence the length of the gestation can be divided in two groups: maternal – the female dog's breed, age and number of previous pregnancies, and fetal – the number and size of fetuses.
The Stages of Pregnancy in Dogs
It's important for dog owners to recognize the stages of pregnancy in dogs– what happens at each stage and what dog owners can do to help. A dog’s pregnancy can be divided in four different phases:
1st phase – lasts for three weeks and it is the least noticeable phase. Except for a little fatigue and a slight loss of appetite, the dog does not show any significantly visible signs. However, the skin on the dog’s abdomen and around the nipples becomes thinner than usual. At three weeks, a veterinarian can diagnose pregnancy in a lean-bodied female by palpating her abdomen and detecting developing fetuses through the abdominal wall.
2nd phase – lasts from the 4th to the 6th week. During this phase, a caring and observing owner may notice slight weight gain and slight increase of the dog’s nipples.
3rd phase – lasts from the 6th to the 9th week. During this phase, the dog’s belly becomes so big it is impossible to miss. Additionally, milk production begins. At this point the dog’s appetite is variable and ranges from significantly decreased to voracious eating.
4th phase – this is the shortest phase but most eventful from a behavioral point of view. During this phase the dog becomes restless. She wanders from place to place while constantly seeking for a quiet place where she can give birth in peace and without being interrupted. Simply put, at this point the dog looks agitated.
A good way for the owner to find out when the dog is due is by measuring her body temperature. This is because the dog’s body temperature tends to drop significantly just before giving birth (98 degrees). Another indication that the delivery is near is the appearance of a clear, liquid discharge. Once the discharge appears, the owner should clean the vulva and the areas around the nipples with a clean cloth soaked in warm water.
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Keep an Eye on These Factors
Regardless of the phase of the pregnancy the dog is in, the dog owner is supposed to pay attention on these three particularly important factors:
- The appearance of abnormal bleeding which is usually a sign of an abortion.
- Morning sickness episodes that appear as a natural defensive mechanisms through which the mother minimizes her fetuses’ exposure to toxins.
- Keeping the pregnant mother well-nourished. Years ago, nutritionists discovered that well-nourished mothers do not just give birth to puppies that are healthier than others. In fact, their pups crawl, walk, run and play earlier, learn faster and have fewer emotional problems than puppies from malnourished mothers. In that name, it should be noted that during the first five weeks, the pregnant dog needs only a balanced diet with normal-sized meals. After the 5th week, her energy consumption should be increased by 10 percent per week until the birth.
The Journey From Egg to Fetus
How do pups develop in the womb? In the section on the stages of pregnancy in dogs it was discussed what happens to the expecting dog, but what happens to the developing puppies? Here is a description of the journey from egg to fetus.
Fertilization takes place in the fallopian tubes (oviducts). After fertilization of the eggs, the zygotes migrate down the two tubes of the uterus. The migration lasts for about 6 to 10 days.
The dog’s womb consists of two pencil-thin tubes or horns. Under the influence of minute amounts of body chemicals called cytokines, the zygotes attach themselves to the uterine wall and become evenly spaced along each uterine horn. The positioning along the horn may influence the health and size of the pup. The best positions are in the middle sections of each horn.
After the attachment, that usually lasts for 8 to 10 days, they develop into two parts – embryos that become fetuses and placentas which draw nutrients from the mother’s bloodstream for the fetuses. Larger placentas offer better nutrition for the developing pups.
For the first two weeks, the embryo cells differentiate into all the cells needed for the body’s development. Once an embryo has all of its main structures it is called a fetus. At two weeks, the fetus is minute but has a head, spine, limb buds and tail. It is nourished by the yolk sac. This is the most critical stage of development. Any drugs or diseases in the mother can severely damage the fetuses.
By the end of three weeks, all of the tissues and organs necessary for life have developed. This stage is roughly the equivalent of three month’s development in a human fetus. At three weeks, a vet can diagnose pregnancy in a lean-bodied female by feeling her abdomen and detecting individual developing fetuses through the abdominal wall.
By six weeks, the fetus has the form of a miniature dog. Skin color, hair, claws and eyelids are all distinct.
At 42-45 days, the pups’ skeletons can be seen on X-rays and their skulls can be felt through the abdominal wall. From now until birth, three weeks later, the fetus simply grows. However, it still depends on nourishment via the placenta and its lungs are not yet capable of taking in oxygen.
Reproduction is the very essence of life. Strip away all other concerns and it is the core reason for existence. By domesticating the dog, we took control over its destiny. But in a wonderfully perverse way, our control of the dog’s reproductive system has meant the dog has spread around the world in a way it could never have done on its own. In a nutshell, the dog’s domestication is a reproduction success story.
About the Author
Dr. Ivana Crnec is a graduate of the University Sv. Kliment Ohridski’s Faculty of Veterinary Medicine in Bitola, Republic of Macedonia. She is a certified nutritionist and is certified in HAACP food safety system implementation.
She currently practices as a veterinarian in Bitola and is completing her postgraduate studies in the Pathology of Domestic Carnivores at the Faculty of Veterinary Medicine in Zagreb, Croatia.
Ivana’s research has been published in international journals, and she regularly attends international veterinary conferences.