Reproduction

Dog Reproduction: Estrous Cycle, Ovulation, Breeding Time & Gestation in the Bitch

Q: How long is a dog pregnant?

62–64 days from the day of ovulation, 64–66 days from the LH surge and 58–72 days from breeding at an unknown stage of estrus.

Updated 1 Nov 20263 sources

Key reproductive figures for the dog from the MSD Veterinary Manual reproductive-cycle and gestation tables ^[1]^[2] and the Merck chapter on whelping and queening ^[3].

Key figures

Feature	Dog	Source
Age at puberty	6–24 months; earlier in smaller breeds, later in larger breeds	^[1]
Cycle	Monestrous all year; 6–7 months	^[1]
Proestrus bleeding	Lasts 7–10 days	^[1]
Duration of estrus	9 days (3–21)	^[1]
Ovulation	Usually 1–3 days after the onset of estrus; ova are shed before the first polar body has been extruded (primary oocyte)	^[1]
Best time to breed	Day 2 after ovulation	^[1]
First estrus after whelping	4–5 months	^[1]

Gestation depends on the reference event

Counted from	Gestation	Source
Day of ovulation (determined by progesterone or LH monitoring)	62–64 days	^[2]
LH surge / initial rise in progesterone	64–66 days	^[3]
Breeding at an unknown stage of estrus	58–72 days	^[2]
First day the female permitted breeding	58–72 days	^[3]
First day of diestrus	56–58 days	^[3]

Frequently asked questions

How often does a dog come into heat?

The bitch is monestrous all year, with cycles 6–7 months apart ^[1].

When is the best time to breed a dog?

Day 2 after ovulation; ovulation usually occurs 1–3 days after the onset of estrus ^[1].

How long is a dog pregnant?

62–64 days from the day of ovulation ^[2], 64–66 days from the LH surge ^[3] and 58–72 days from breeding at an unknown stage of estrus ^[2].

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References

Features of the Reproductive Cycle (table)MSD Veterinary Manual
Approximate Gestation Periods (table)MSD Veterinary Manual
Whelping and Queening in Bitches and QueensDavidson AP — Merck Veterinary Manual · reviewed 2025

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