Complete Guide to Dog Breeding and Pregnancy Management | Estrous Cycle, Breeding Timing, and Gestation Period Management

Foundational Knowledge Required for Dog Breeding

Dog breeding is not simply a matter of "putting a male and female together." To produce healthy puppies as a breeder, accurate understanding of the estrous cycle, screening for pedigree and genetic diseases, determining optimal breeding timing through progesterone levels, and proper management throughout gestation are essential. This guide systematically explains the complete picture of breeding and pregnancy management that beginner to intermediate breeders should practice.

Understanding the Canine Estrous Cycle (Heat)

The female dog's estrous cycle consists of four stages.

Proestrus (Proestral Stage): This period is characterized by vulvar swelling and bloody discharge, typically lasting 7-10 days. During this stage, the female shows interest in males but does not accept breeding. Hormonally, estrogen begins to rise while progesterone remains low.

Estrus (Estral Stage): Discharge becomes lighter, and the female displays receptivity to males, assuming a standing position. This stage typically lasts 5-9 days and ovulation occurs during this period. This is the optimal phase for breeding.

Diestrus (Diestral Stage): Regardless of pregnancy status, progesterone remains elevated during this period (approximately 60 days). This is when false pregnancy (pseudopregnancy) is most likely to occur.

Anestrus (Anestral Stage): A hormonally dormant period lasting until the next proestrus. Small breeds typically cycle twice yearly, while large breeds typically cycle once yearly.

Identifying Optimal Breeding Day Using Progesterone Testing

Simply breeding immediately after heat begins carries the risk of significantly reduced conception rates due to timing variation. The most accurate method is progesterone testing.

When blood progesterone levels reach 2-5 ng/mL, ovulation is approaching; levels of 5 ng/mL or above indicate that ovulation has occurred. Eggs become fertilizable 2-3 days after ovulation, making the period when progesterone is 5-10 ng/mL (2-3 days post-ovulation) the optimal breeding window.

Testing is performed at a veterinary clinic, with standard protocol being measurements every 2 days beginning in late proestrus. Cost is approximately ¥3,000-8,000 per test, but it is well worth the investment to improve litter size and conception rates. Combining with vaginal smear cytology further increases accuracy.

Breeding Methods and Precautions

Breeding can occur on either the male's or female's territory depending on individual temperament, but it is generally easier for the male to perform calmly on his own territory. When semen transport between breeders is difficult or distance is a factor, artificial insemination (AI) is an option. Artificial insemination using chilled semen must be performed within 24-48 hours, while frozen semen requires even more precise timing.

Before breeding, the following must be verified for both individuals:

• Genetic disease screening (breed-specific risk factors such as hip dysplasia and progressive retinal atrophy)
• Brucellosis testing (infected dogs cannot be bred)
• Vaccination history and health status confirmation
• Age and size compatibility (first breeding at 2-3 years; first breeding at 5+ years carries increased risk)

Pregnancy Confirmation Methods

Beginning around days 25-28 post-breeding, gestational sacs can be visualized via ultrasound at a veterinary clinic. If a fetal heartbeat is detected at this point, pregnancy is likely established. For more accurate fetal count determination, radiography at days 45-55 of pregnancy is effective (when skeletal structures are visible). Knowing fetal count serves as a reference to confirm all puppies have been delivered at parturition.

Relaxin hormone testing via blood work is also used for pregnancy confirmation, though positive results typically don't appear until 30+ days post-breeding.

Nutrition Management During Pregnancy

The canine gestation period averages 63 days (range 58-68 days). During the first half of pregnancy (weeks 1-4), normal adult dog food is appropriate. From the second half (week 5 onward), gradually increase food amount; shortly before delivery, caloric intake should reach approximately 1.5-2 times normal levels.

Many breeders recommend switching to puppy formula or all-life-stage diet in the second half of pregnancy in preparation for nursing. Excessive calcium supplementation increases the risk of postpartum hypocalcemia (eclampsia), so during pregnancy, calcium should come from natural diet sources, and supplements should be used only under veterinary guidance.

Exercise and Lifestyle Management During Pregnancy

Normal exercise is acceptable during the first half of pregnancy, but during the second half (week 5 onward), avoid strenuous exercise, jumping, and rough play. Minimize stress by providing a quiet, safe environment and reducing unfamiliar visitors and noise.

Vaccination should be avoided during pregnancy. Additionally, flea and tick prevention products are limited during pregnancy, so confirm with your veterinarian beforehand.

Pre-Delivery Preparation

Two weeks before the due date, set up a whelping box to give the dam time to acclimate to it beforehand. Size should allow the dam to stretch out fully (1.5-2 times her body length), with guard rails (pig rails) to prevent puppies from being crushed against the sides. Bedding should be clean and non-slip, such as fleece material. Maintain environmental temperature at 28-30°C (29-32°C for newborn puppies).

It is also important to pre-identify an emergency veterinary clinic with after-hours availability for pre- and post-delivery support. Mental preparation and contingency planning for potential need of emergency cesarean section or resuscitation procedures is part of a breeder's responsibility.