What question did this study set out to answer?

To evaluate the impact of age at first lambing, litter size, and environmental conditions on longevity in a prolific sheep breed.

April 5, 2025animalOpen Access

Early life reproductive investment affects longevity in ewes

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Authors

LKL. S. KierkegaardNorwegian University of Life Sciences NFN.C. FriggensAgroParisTech GSGeir SteinheimNorwegian University of Life Sciences

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Implication

Cohort study reveals reduced longevity linked to earlier lambing and larger litters in ewes, highlighting trade-offs between early reproduction and lifespan.

Key Points

To evaluate the impact of age at first lambing, litter size, and environmental conditions on longevity in a prolific sheep breed.
Evaluated lifetime performance records from 550,884 Norwegian White Sheep born between 2000 and 2013 across Norway.
Used a linear mixed model with fixed effects for age at first lambing (1- vs. 2-year-olds), litter size, county, parturition timing, cross-fostering, and weaning success, with herd-by-year as a random effect.
Ewes mated as lambs had a predicted lifespan of 1,548 days (4.2 years) compared to 1,700 days (4.7 years) for ewes mated as 2-year-olds.
A curvilinear relationship was observed between litter size and lifespan: predicted lifespan increased from 1,272 days (3.5 years) with 0 lambs to 1,618 days (4.4 years) with 1 lamb, then decreased to 1,468 days (4.0 years) with 4 lambs.
Among ewes rearing fewer lambs than born, peak lifespan for those mated as lambs was 1,504 days (4.1 years) at litter size 1, compared to 1,650 days (4.5 years) at litter size 2 for those first mated at age 2.

Cite This Study

Kierkegaard et al. (2025) studied this question.

synapsesocial.com/papers/6a11c4b6224d77b8d56182e2 https://doi.org/10.1016/j.animal.2025.101504

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April 5, 2025animalOpen Access

Early life reproductive investment affects longevity in ewes

View Full Paper

Ask AI

Bookmark

Authors

LKL. S. KierkegaardNorwegian University of Life Sciences NFN.C. FriggensAgroParisTech GSGeir SteinheimNorwegian University of Life Sciences

Discussion

Member takes

Implication

Cohort study reveals reduced longevity linked to earlier lambing and larger litters in ewes, highlighting trade-offs between early reproduction and lifespan.

Key Points

To evaluate the impact of age at first lambing, litter size, and environmental conditions on longevity in a prolific sheep breed.
Evaluated lifetime performance records from 550,884 Norwegian White Sheep born between 2000 and 2013 across Norway.
Used a linear mixed model with fixed effects for age at first lambing (1- vs. 2-year-olds), litter size, county, parturition timing, cross-fostering, and weaning success, with herd-by-year as a random effect.
Ewes mated as lambs had a predicted lifespan of 1,548 days (4.2 years) compared to 1,700 days (4.7 years) for ewes mated as 2-year-olds.
A curvilinear relationship was observed between litter size and lifespan: predicted lifespan increased from 1,272 days (3.5 years) with 0 lambs to 1,618 days (4.4 years) with 1 lamb, then decreased to 1,468 days (4.0 years) with 4 lambs.
Among ewes rearing fewer lambs than born, peak lifespan for those mated as lambs was 1,504 days (4.1 years) at litter size 1, compared to 1,650 days (4.5 years) at litter size 2 for those first mated at age 2.

Cite This Study

Kierkegaard et al. (2025) studied this question.

synapsesocial.com/papers/6a11c4b6224d77b8d56182e2 https://doi.org/10.1016/j.animal.2025.101504

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