To calculate Ovulation cycle, using dog heat cycle calculator, enter last cycle onset date: Input the date when your dog’s last proestrus phase began (typically marked by vulvar swelling and bloody discharge).
Select Canine Size Category: Toy (under 10 lbs/4.5 kg): Yorkshire Terriers, Chihuahuas, Toy Poodles
Small (10-25 lbs/4.5-11 kg): Beagles, Cocker Spaniels, Miniature Schnauzers
Medium (25-50 lbs/11-23 kg): Border Collies, Australian Shepherds, Bulldogs
Large (50-100 lbs/23-45 kg): Labrador Retrievers, German Shepherds, Boxers
Giant (over 100 lbs/45 kg): Great Danes, Saint Bernards, Newfoundlands
🐕 Dog Heat Cycle Calculator
Indicate Reproductive Maturity:
Juvenile (first year post-puberty): Cycles may be irregular and unpredictable
Adult (2-7 years): Typically exhibit stable, predictable cycles
Senior (7+ years): May experience decreased reproductive efficiency or irregular cycles
Female dogs (bitches) experience reproductive cycles known as estrous cycles, commonly called “heat cycles.” Dogs typically have 2-3 cycles per year rather than monthly cycles. These cycles consist of four distinct phases: proestrus, estrus, diestrus, and anestrus, with the visible “heat” period encompassing proestrus and estrus phases.
Dog Heat Cycle Calculator Results
The calculator provides the following projections:
- Projected Next Cycle Onset: Estimated date of next proestrus onset
- Interval Countdown: Approximate days until next anticipated cycle begins
- Cycle Phase Indicator: Visual representation of current reproductive phase
- Fertility Window Estimation: Projected optimal breeding period (typically days 9-14 of the cycle, during standing estrus)
- Breed-Specific Information: Average interestrous interval data for your dog’s size category
Cycle Duration by Breed Size
Scientific research indicates breed-size correlations with interestrous intervals:
| Size Category | Average Interestrous Interval | Typical Range |
|---|---|---|
| Toy | 5 months (150 days) | 4-6 months |
| Small | 6 months (180 days) | 5-7 months |
| Medium | 7 months (210 days) | 6-8 months |
| Large | 8 months (240 days) | 7-9 months |
| Giant | 10 months (300 days) | 8-12 months |
Signs of Estrous Phases
- Proestrus (6-11 days):
- Vulvar swelling and edema
- Sanguineous (bloody) discharge
- Male attraction without receptivity
- Increased urination frequency
- Estrus (5-9 days):
- Softening of vulvar edema
- Discharge changing from red to straw-colored
- Flagging (deviation of tail)
- Lordosis (standing position) and receptivity to males
- Diestrus (60-90 days):
- Cessation of male interest
- Vulvar involution
- Pregnancy or pseudopregnancy may occur
- Anestrus (Variable):
- Period of reproductive quiescence
- Duration varies significantly by breed size
References and Additional Resources
- American Veterinary Medical Association – Spaying and Neutering
- Cornell University College of Veterinary Medicine – Reproductive Cycles
- American Kennel Club – Breeding & Whelping
- UC Davis School of Veterinary Medicine – Canine Reproduction
- Merck Veterinary Manual – Canine Estrous Cycle
- Society for Theriogenology – Resources