Reproduction

Sheep Reproduction: Breeding Season, Estrous Cycle, Ram Effect & Gestation

Q: How long is the estrous cycle of a ewe?

17 days (14–20) in the MSD Veterinary Manual; Sheep 101 & 201 gives 13–19 days, averaging 17.

Q: How long is a sheep pregnant?

The MSD table gives 150 days; Sheep 101 & 201 gives an average gestation length of 142 to 152 days.

Updated 1 Nov 20263 sources

Key reproductive figures for sheep from the MSD Veterinary Manual ^[1]^[2] and from Sheep 101 & 201 by Susan Schoenian ^[3].

Key figures

Feature	Sheep	Source
Age at puberty	6–9 months	^[1]
Cycle	Seasonally polyestrous, early autumn to winter; 17 days (14–20)	^[1]
Duration of estrus	24–36 h	^[1]
Ovulation	Near the end of estrus	^[1]
Best time to breed	18–20 h after the onset of estrus	^[1]
First estrus after lambing	Next autumn	^[1]
Gestation	150 days	^[2]

Breeding season and the ram effect

Most sheep are seasonally polyestrous and short-day breeders ^[3].
Signs of estrus in the ewe are much less pronounced than in the cow or doe ^[3].
The ram effect: non-cycling ewes are stimulated to ovulate by the sudden introduction of an intact male or a vasectomized (teaser) ram ^[3].
Ewe lambs should not be bred until they reach approximately 70 percent of their mature size (weight) ^[3].

How the sources compare

Feature	MSD Veterinary Manual ^[1]^[2]	Sheep 101 & 201 ^[3]
Age at puberty	6–9 months	Most ewe lambs 5–12 months
Estrous cycle	17 days (14–20)	13–19 days, average 17
Duration of estrus	24–36 h	Approximately 24–36 h
Ovulation	Near the end of estrus	Mid to late estrus
Gestation	150 days	Average gestation length varies from 142 to 152 days

Frequently asked questions

How long is the estrous cycle of a ewe?

17 days (14–20) in the MSD Veterinary Manual ^[1]; Sheep 101 & 201 gives 13–19 days, averaging 17 ^[3].

When is the breeding season of sheep?

Sheep are seasonally polyestrous, from early autumn to winter ^[1]; most sheep are short-day breeders ^[3].

What is the ram effect?

Non-cycling ewes are stimulated to ovulate by the sudden introduction of an intact male or a vasectomized (teaser) ram ^[3].

How long is a sheep pregnant?

The MSD table gives 150 days ^[2]; Sheep 101 & 201 gives an average gestation length of 142 to 152 days ^[3].

Related tools and references

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References

Features of the Reproductive Cycle (table)MSD Veterinary Manual
Approximate Gestation Periods (table)MSD Veterinary Manual
Reproduction in the ewe (Sheep 201)Schoenian S — Sheep 101 & 201 · 2019

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