Pregnancies in dogs last 58-65 days (62 days on average), and in some cases up to 72 days.
The length of pregnancy and the course of labor depend on:
The number of fetuses;
The timing of mating and the age of the expectant mother;
conditions under which the pregnant bitch is kept;
The health of the bitch and possible abnormalities in the pregnancy.
How long a dog’s pregnancy lasts
Dependence of the duration of pregnancy on the number of fetuses
With a large number of puppies, greatly stretching the uterus and already actively moving, labor can occur even on day 58. An earlier term is considered abnormal, and the puppies usually do not survive. A bitch may also slightly overpart her offspring if they are small.
Physiologically, dogs are multi-bred animals, but the number of embryos developing in the uterus can range from 1 to 12 or even more, determined by the following circumstances:
- Breed size. Small ornamental dogs usually have few puppies (1 to 4), medium-sized breeds have 4 to 7, and large breeds have 6 to 12;
- heredity. Different members of the same breed may have a relative high or low fertility, and the tendency to do so is transmitted within the bloodline;
- age of the dog. A bitch who is too young and early mated (first heat at 6-9 months), or, on the contrary, an older bitch may have fewer puppies than usual in the breed. In the first case this is due to the fact that the body has not yet fully formed and is not able to fully bear offspring, and in the second – already launched involutionary processes in the reproductive system;
- hormonal background. In some bitches some or all embryos suddenly undergo resorption (resorption). This occurs before the 45th day of intrauterine development and is caused by a drop in progesterone levels, the hormone responsible for normal pregnancy, but may also be associated with viral infections (herpes), stress and endometritis;
- day of mating. If a bitch is ligated too early or too late, the number of conceived fetuses will be low;
- The quality of the male sperm. If the father’s sperm has a high number of defective and dead spermatozoa, her fertilizing ability will be low. There is also a complex of other factors that can be determined by a spermogram.
Dependence of pregnancy length on the day of mating and age of the dog
Pregnancy can last up to 65-70 days if the bitch is littered too early, i.e. a few days before ovulation. In fact, the increase in pregnancy is explained by the fact that healthy sperm retain their fertilizing activity for 2-5 days in the birth canal of the female and simply “wait” for the moment to successfully join with the eggs.
The shift in the days of heat to the end of heat is most often observed in older bitches, which should therefore not be mated until the 14th day of heat.
To accurately determine the right day for mating, a combination of methods is used, including external inspection of the bitch, cytological examination of the vaginal smear and determination of the progesterone concentration in the blood.
Relationship of pregnancy duration to the dog’s environment
Pregnancy, quantity and quality of future puppies are negatively affected by factors such as:
Poor housing conditions of the female (unsanitary, cold, overcrowding of animals in the same area);
Insufficient caloric intake, depleted in protein, vitamins and minerals;
Internal (worms, protozoa) and external parasites (fleas, cockroaches, mites), as well as chronic infections and diseases of internal organs, especially gynecological;
Excessive weight and lack of exercise;
Excessive and brutal physical activity, overexertion;
bumping and abuse.
Dependence of pregnancy duration on health status
All of the above leads to the weakening of the female body and disrupts the intrauterine development of fetuses, manifesting in one or another pathology, viz:
spontaneous abortions and premature births;
Pregnancies that do not take place;
Abnormal over delivery;
The birth of small, ugly, weakened and/or non-viable babies.
It should be noted that a conscientious owner should monitor his or her dog’s pregnancy carefully, noting the slightest warning signs. If the bitch is not feeling well, has a discharge from the vaginal tract, has gone into labor prematurely, or is not in labor, a visit to the veterinarian should be warranted.