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Research article - Peer-reviewed, 2021

No evidence that selection for egg production persistency causes loss of bone quality in laying hens

Dunn, Ian C.; De Koning, Dirk-Jan; McCormack, Heather A.; Fleming, Robert H.; Wilson, Peter W.; Andersson, Bjorn; Schmutz, Matthias; Benavides, Cristina; Dominguez-Gasca, Nazaret; Sanchez-Rodriguez, Estefania; Rodriguez-Navarro, Alejandro B.


Background The physiological adaptations that have evolved for egg laying make hens susceptible to bone fractures and keel bone damage. In modern laying hen breeds, longer periods of egg laying could result in a greater risk of poor bone quality, and selection for increased egg production has frequently been stated to be a cause. However, the existing literature does not support this hypothesis. To test the hypothesis that egg production is associated with quality, breaking strength and density of bone, genetic correlations between these traits were estimated in White Leghorn and Rhode Island Red breeds. Genetic correlations of cortical and medullary bone material chemical properties with bone quality were also estimated, in order to identify methods to improve bone quality with appropriately targeted measurement of key traits. Results Estimates of heritability for bone quality traits were moderate (0.19-0.59) for both White Leghorn and Rhode Island Red breeds, except for the keel bone trait, which had a heritability estimate equal to zero. There was no evidence for genetic or phenotypic relationships between post-peak egg production and bone quality. In the White Leghorn breed, the estimate of the genetic correlation between pre-peak production/age at first egg and bone quality was significant and negative (- 0.7 to - 0.4). Estimates of heritability of thermogravimetric measurements of tibial medullary bone mineralisation were significant (0.18-0.41), as were estimates of their genetic correlations with tibia breaking strength and density (0.6-0.9). Conclusions The low genetic correlation of post-peak egg production with bone quality suggests that selection for increased persistency of egg production may not adversely affect bone quality. Onset of puberty and mineralisation of the medullary bone, which is a specialised adaptation for egg laying, were identified as important factors associated with the quality of the skeleton later during egg production. These are traits for which genetic, as well as environmental and management factors can positively impact the overall quality of the skeleton of laying hens.

Published in

Genetics Selection Evolution
2021, volume: 53, number: 1, article number: 11
Publisher: BMC

Authors' information

Dunn, Ian C.
University of Edinburgh
Swedish University of Agricultural Sciences, Department of Animal Breeding and Genetics
McCormack, Heather A.
University of Edinburgh
Fleming, Robert H.
University of Edinburgh
Wilson, Peter W.
University of Edinburgh
Andersson, Björn
Lohmann Tierzucht GmbH
Schmutz, Matthias
Lohmann Tierzucht GmbH
Benavides, Cristina
University of Granada
Dominguez-Gasca, Nazaret
University of Granada
Sanchez-Rodriguez, Estefania
University of Granada
Rodriguez-Navarro, Alejandro B.
University of Granada

Sustainable Development Goals

SDG12 Responsible consumption and production

UKÄ Subject classification

Animal and Dairy Science
Genetics and Breeding

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