Dog Breeding Guide: Heat, Mating, Pregnancy to Whelping
The whole dog breeding cycle in order, with the tools for each stage: heat detection, progesterone-timed mating, the 63 days of pregnancy, whelping, and weaning.
Quick Answer
A bitch cycles roughly every 5 to 12 months (twice a year for most, once for some giants), stands for the male around days 9 to 14 of heat, and carries pups for 63 days (range 58 to 68). Progesterone testing pinpoints the fertile day. Dogs have no breeding season, so any month works: plan around whelping weather instead. Enter the mating date in the dog gestation calculator for exact dates and milestones.
1. Heat Cycle: Knowing When She Is Ready
Most bitches cycle about every six months, though the normal spread runs five to twelve: small breeds can cycle three times a year, giants only once. Proestrus brings a swollen vulva and bloody discharge for roughly nine days, then she stands for the male during estrus, usually days 9 to 14. The fertile window sits late in that standing heat, when ovulation releases eggs that are ready two to three days later.
Tools for this stage: dog heat cycle calculator
2. Breeding: Timed to Ovulation
Progesterone bloodwork beats guessing: it tells you the day she ovulated so you mate that day and the next for two chances at the eggs. Natural cover, fresh AI, and chilled semen all work on that loose window, while frozen semen lives only hours and needs precise timing. Write the mating date down the same day, because every due date and milestone below depends on it.
Tools for this stage: dog gestation calculator for the due date
3. Pregnancy: The 63 Days
Gestation averages 63 days with a normal range of 58 to 68, counted from the fertile mating. The first month looks like nothing at all: pinking nipples and a softening belly show by week 4, and an ultrasound or blood test confirms by day 30. Keep feed at maintenance until the final third, then switch to puppy food, because the pups do nearly all their growing in the last two weeks.
Tools for this stage: dog pregnancy symptoms · week by week pregnancy timeline
4. Whelping Prep: The Final Week
Introduce the whelping box two weeks early so she settles into it herself, bedded with washable pads and a safely hung heat lamp over one corner. Take her rectal temperature twice a day in the final week: a drop below 100 F means pups within about 24 hours. Stage the kit before day 58: thermometer, lubricant, scissors, iodine, clean towels, and the vet's after-hours number.
Tools for this stage: dog whelping calculator · whelping box setup · printable whelping kit checklist
5. Whelping: Labor and When to Help
Stage one is restlessness, panting, and nesting for 6 to 12 hours; once hard straining starts, the first pup should arrive within 30 to 60 minutes. Call the vet if she strains an hour with no puppy, if more than two quiet hours pass between pups, or if green-black discharge appears with no pup following. Pups should be dried, breathing, and nursing within their first hour.
Tools for this stage: dog labor signs
6. Puppy Care and Weaning
Weigh the litter daily on a kitchen scale: steady daily gains of 5 to 10 percent of body weight mean everyone is nursing well. Start a mush of puppy food at 3 to 4 weeks and wean fully onto solid food by 6 to 8 weeks. Worming starts around 2 weeks per your vet's protocol, and pups go to new homes no earlier than 8 weeks.
Tools for this stage: puppy weight calculator
Dog Breeding Month Chart
Mating month on the left, whelping month on the right, using the 63 day average (two months and a few days). Dogs are not seasonal breeders, so every row is possible: the note column tells you what that whelping weather means for you.
| Breed in | Pups arrive | Plan for |
|---|---|---|
| January | March | Spring whelping: mild weather, easiest season for newborns |
| February | April | Spring whelping: mild weather, easiest season for newborns |
| March | May | Spring whelping: mild weather, easiest season for newborns |
| April | June | Summer whelping: keep the box cool, pups overheat fast |
| May | July | Summer whelping: keep the box cool, pups overheat fast |
| June | August | Summer whelping: keep the box cool, pups overheat fast |
| July | September | Fall whelping: comfortable, add heat by weaning time |
| August | October | Fall whelping: comfortable, add heat by weaning time |
| September | November | Fall whelping: comfortable, add heat by weaning time |
| October | December | Winter whelping: heat lamp and a draft-free room |
| November | January | Winter whelping: heat lamp and a draft-free room |
| December | February | Winter whelping: heat lamp and a draft-free room |
Exact dates from your own mating day, plus week by week milestones, come from the dog gestation calculator.
Frequently Asked Questions
At what age should a dog be bred for the first time?
Wait until the second or third heat and full maturity, typically 18 to 24 months, later for giant breeds. That schedule lets you finish health testing first: hips, elbows, eyes, and breed-specific genetic checks before the breeding, not after. Breeding on a first heat, or before she has finished growing, puts both the bitch and the litter at risk.
What does progesterone testing do for breeding dogs?
It is a series of blood draws that tracks the hormone rise before ovulation, so you breed on the fertile day instead of guessing from discharge and flagging. Most matings land two to four days after the numbers show ovulation has happened, and frozen semen is timed even tighter. Expect three or four draws across heat week, more for frozen AI.
What decides how many puppies are in a litter?
Breed and body size set the ceiling: a large breed can have ten or more pups while a Chihuahua may have one or two. Within that, litter size moves with the dam's age (litters grow until around age 3 to 4, then decline), her conditioning, sire fertility, and how precisely mating matched ovulation. First litters usually run a pup or two smaller than later ones.
When does a whelping dog need help from a vet?
In active labor, call for hard straining 30 to 60 minutes with no puppy, more than two hours between pups once delivery is rolling, fresh bleeding, or green-black discharge with no pup arriving. Before labor, call if day 68 passes with nothing happening. Either way, have the vet check the pups and the dam's calcium and milk supply within a day of whelping.
How often can you breed a bitch?
Physically she can conceive every heat, but that pace drains calcium, body condition, and uterine health. Most responsible breeders breed no more than once a year and skip cycles for small breeds, older bitches, or any C-section or difficult delivery. Retire her from breeding well before old age: around 8 years old is a common outside limit to agree on with your vet.
Record It All on Paper
Litters improve on written dates: the mating day, twice-daily weights, and who went home when. Our printable breeding record sheets and whelping logs print free, no signup.
Kanika
Researched and reviewed by Kanika, founder of GestationCalc. All gestation data is verified against primary veterinary and agricultural sources before publication.
Last reviewed: September 26, 2026